Arquivo da tag: Evolucionismo

Scientists Seek to Update Evolution (Quanta Magazine)

Recent discoveries have led some researchers to argue that the modern evolutionary synthesis needs to be amended. 

By Carl Zimmer. November 22, 2016

Douglas Futuyma, a biologist at Stony Brook University, defends the “Modern Synthesis” of evolution at the Royal Society earlier this month.  Kevin Laland looked out across the meeting room at a couple hundred people gathered for a conference on the future of evolutionary biology. A colleague sidled up next to him and asked how he thought things were going.

“I think it’s going quite well,” Laland said. “It hasn’t gone to fisticuffs yet.”

Laland is an evolutionary biologist who works at the University of St. Andrews in Scotland. On a chilly gray November day, he came down to London to co-host a meeting at the Royal Society called “New Trends in Evolutionary Biology.” A motley crew of biologists, anthropologists, doctors, computer scientists, and self-appointed visionaries packed the room. The Royal Society is housed in a stately building overlooking St. James’s Park. Today the only thing for Laland to see out of the tall meeting-room windows was scaffolding and gauzy tarps set up for renovation work. Inside, Laland hoped, another kind of renovation would be taking place.

In the mid-1900s, biologists updated Darwin’s theory of evolution with new insights from genetics and other fields. The result is often called the Modern Synthesis, and it has guided evolutionary biology for over 50 years. But in that time, scientists have learned a tremendous amount about how life works. They can sequence entire genomes. They can watch genes turn on and off in developing embryos. They can observe how animals and plants respond to changes in the environment.

As a result, Laland and a like-minded group of biologists argue that the Modern Synthesis needs an overhaul. It has to be recast as a new vision of evolution, which they’ve dubbed the Extended Evolutionary Synthesis. Other biologists have pushed back hard, saying there is little evidence that such a paradigm shift is warranted.

This meeting at the Royal Society was the first public conference where Laland and his colleagues could present their vision. But Laland had no interest in merely preaching to the converted, and so he and his fellow organizers also invited prominent evolutionary biologists who are skeptical about the Extended Evolutionary Synthesis.

Both sides offered their arguments and critiques in a civil way, but sometimes you could sense the tension in the room — the punctuations of tsk-tsks, eye-rolling, and partisan bursts of applause.

But no fisticuffs. At least not yet.

Making Evolution as We Know It

Every science passes through times of revolution and of business as usual. After Galileo and Newton dragged physics out of its ancient errors in the 1600s, it rolled forward from one modest advance to the next until the early 1900s. Then Einstein and other scientists established quantum physics, relativity and other new ways of understanding the universe. None of them claimed that Newton was wrong. But it turns out there’s much more to the universe than matter in motion.

Evolutionary biology has had revolutions of its own. The first, of course, was launched by Charles Darwin in 1859 with his book On the Origin of Species. Darwin wove together evidence from paleontology, embryology and other sciences to show that living things were related to one another by common descent. He also introduced a mechanism to drive that long-term change: natural selection. Each generation of a species was full of variations. Some variations helped organisms survive and reproduce, and those were passed down, thanks to heredity, to the next generation.

Darwin inspired biologists all over the world to study animals and plants in a new way, interpreting their biology as adaptations produced over many generations. But he succeeded in this despite having no idea what a gene was. It wasn’t until the 1930s that geneticists and evolutionary biologists came together and recast evolutionary theory. Heredity became the transmission of genes from generation to generation. Variations were due to mutations, which could be shuffled into new combinations. New species arose when populations built up mutations that made interbreeding impossible.

In 1942, the British biologist Julian Huxley described this emerging framework in a book called Evolution: The Modern Synthesis. Today, scientists still call it by that name. (Sometimes they refer to it instead as neo-Darwinism, although that’s actually a confusing misnomer. The term “neo-Darwinism” was actually coined in the late 1800s, to refer to biologists who were advancing Darwin’s ideas in Darwin’s own lifetime.)

The Modern Synthesis proved to be a powerful tool for asking questions about nature. Scientists used it to make a vast range of discoveries about the history of life, such as why some people are prone to genetic disorders like sickle-cell anemia and why pesticides sooner or later fail to keep farm pests in check. But starting not long after the formation of the Modern Synthesis, various biologists would complain from time to time that it was too rigid. It wasn’t until the past few years, however, that Laland and other researchers got organized and made a concerted effort to formulate an extended synthesis that might take its place.

The researchers don’t argue that the Modern Synthesis is wrong — just that it doesn’t capture the full richness of evolution. Organisms inherit more than just genes, for example: They can inherit other cellular molecules, as well as behaviors they learn and the environments altered by their ancestors. Laland and his colleagues also challenge the pre-eminent place that natural selection gets in explanations for how life got to be the way it is. Other processes can influence the course of evolution, too, from the rules of development to the environments in which organisms have to live.

“It’s not simply bolting more mechanisms on what we already have,” said Laland. “It requires you to think of causation in a different way.”

Adding to Darwin

Eva Jablonka, a biologist at Tel Aviv University, used her talk to explore the evidence for a form of heredity beyond genes.

Our cells use a number of special molecules to control which of their genes make proteins. In a process called methylation, for example, cells put caps on their DNA to keep certain genes shut down. When cells divide, they can reproduce the same caps and other controls on the new DNA. Certain signals from the environment can cause cells to change these so-called “epigenetic” controls, allowing organisms to adjust their behavior to new challenges.

Some studies indicate that — under certain circumstances — an epigenetic change in a parent may get passed down to its offspring. And those children may pass down this altered epigenetic profile to their children. This would be kind of heredity that’s beyond genes.

The evidence for this effect is strongest in plants. In one study, researchers were able to trace down altered methylation patterns for 31 generations in a plant called Arabidopsis. And this sort of inheritance can make a meaningful difference in how an organism works. In another study, researchers found that inherited methylation patterns could change the flowering time of Arabidopsis, as well as the size of its roots. The variation that these patterns created was even bigger than what ordinary mutations caused.

After presenting evidence like this, Jablonka argued that epigenetic differences could determine which organisms survived long enough to reproduce. “Natural selection could work on this system,” she said.

While natural selection is an important force in evolution, the speakers at the meeting presented evidence for how it could be constrained, or biased in a particular direction. Gerd Müller, a University of Vienna biologist, offered an example from his own research on lizards. A number of species of lizards have evolved feet that have lost some toes. Some have only four toes, while others have just one, and some have lost their feet altogether.

The Modern Synthesis, Müller argued, leads scientists to look at these arrangements as simply the product of natural selection, which favors one variant over others because it has a survival advantage. But that approach doesn’t work if you ask what the advantage was for a particular species to lose the first toe and last toe in its foot, instead of some other pair of toes.

“The answer is, there is no real selective advantage,” said Müller.

The key to understanding why lizards lose particular toes is found in the way that lizard embryos develop toes in the first place. A bud sprouts off the side of the body, and then five digits emerge. But the toes always appear in the same sequence. And when lizards lose their toes through evolution, they lose them in the reverse order. Müller suspects this constraint is because mutations can’t create every possible variation. Some combinations of toes are thus off-limits, and natural selection can never select them in the first place.

Development may constrain evolution. On the other hand, it also provides animals and plants with remarkable flexibility. Sonia Sultan, an evolutionary ecologist from Wesleyan University, offered a spectacular case in point during her talk, describing a plant she studies in the genus Polygonum that takes the common name “smartweed.”

The Modern Synthesis, Sultan said, would lead you to look at the adaptations in a smartweed plant as the fine-tuned product of natural selection. If plants grow in low sunlight, then natural selection will favor plants with genetic variants that let them thrive in that environment — for example, by growing broader leaves to catch more photons. Plants that grow in bright sunlight, on the other hand, will evolve adaptations that let them thrive in those different conditions.

“It’s a commitment to that view that we’re here to confront,” Sultan said.

If you raise genetically identical smartweed plants under different conditions, Sultan showed, you’ll end up with plants that may look like they belong to different species.

For one thing, smartweed plants adjust the size of their leaves to the amount of sunlight they get. In bright light, the plants grow narrow, thick leaves, but in low light, the leaves become broad and thin. In dry soil, the plants send roots down deep in search of water, while in flood soil, they grow shallow hairlike roots that that stay near the surface.

Scientists at the meeting argued that this flexibility — known as plasticity — can itself help drive evolution. It allows plants to spread into a range of habitats, for example, where natural selection can then adapt their genes. And in another talk, Susan Antón, a paleoanthropologist at New York University, said that plasticity may play a significant role in human evolution that’s gone underappreciated till now. That’s because the Modern Synthesis has strongly influenced the study of human evolution for the past half century.

Paleoanthropologists tended to treat differences in fossils as the result of genetic differences. That allowed them to draw an evolutionary tree of humans and their extinct relatives. This approach has a lot to show for it, Antón acknowledged. By the 1980s, scientists had figured out that our early ancient relatives were short and small-brained up to about two million years ago. Then one lineage got tall and evolved big brains. That transition marked the origin of our genus, Homo.

But sometimes paleoanthropologists would find variations that were harder to make sense of. Two fossils might look in some ways like they should be in the same species but look too different in other respects. Scientists would usually dismiss those variations as being caused by the environment. “We wanted to get rid of all that stuff and get down to their essence,” Antón said.

But that stuff is now too abundant to ignore. Scientists have found a dizzying variety of humanlike fossils dating back to 1.5 to 2.5 million years ago. Some are tall, and some are short. Some have big brains and some have small ones. They all have some features of Homo in their skeletonbut each has a confusing mix-and-match assortment.

Antón thinks that the Extended Evolutionary Synthesis can help scientists make sense of this profound mystery. In particular, she thinks that her colleagues should take plasticity seriously as an explanation for the weird diversity of early Homo fossils.

To support this idea, Antón pointed out that living humans have their own kinds of plasticity. The quality of food a woman gets while she’s pregnant can influence the size and health of her baby, and those influences can last until adulthood. What’s more, the size of a woman — influenced in part by her own mother’s diet — can influence her own children. Biologists have found that women with longer legs tend to have larger children, for example.

Antón proposed that the weird variations in the fossil record might be even more dramatic examples of plasticity. All these fossils date to when Africa’s climate fell into a period of wild climate swings. Droughts and abundant rains would have changed the food supply in different parts of the world, perhaps causing early Homo to develop differently.

The Extended Evolutionary Synthesis may also help make sense of another chapter in our history: the dawn of agriculture. In Asia, Africa and the Americas, people domesticated crops and livestock. Melinda Zeder, an archaeologist at the Smithsonian Institution, gave a talk at the meeting about the long struggle to understand how this transformation unfolded.

Before people farmed, they foraged for food and hunted wild game. Zeder explained how many scientists treat the behavior of the foragers in a very Modern Synthesis way: as finely tuned by natural selection to deliver the biggest payoff for their effort to find food.

The trouble is that it’s hard to see how such a forager would ever switch to farming. “You don’t get the immediate gratification of grabbing some food and putting it in your mouth,” Zeder told me.

Some researchers suggested that the switch to agriculture might have occurred during a climate shift, when it got harder to find wild plants. But Zeder and other researchers have actually found no evidence of such a crisis when agriculture arose.

Zeder argues that there’s a better way of thinking about this transition. Humans are not passive zombies trying to survive in a fixed environment. They are creative thinkers who can change the environment itself. And in the process, they can steer evolution in a new direction.

Scientists call this process niche construction, and many species do it. The classic case is a beaver. It cuts down trees and makes a dam, creating a pond. In this new environment, some species of plants and animals will do better than others. And they will adapt to their environment in new ways. That’s true not just for the plants and animals that live around a beaver pond, but for the beaver itself.

When Zeder first learned about niche construction, she says, it was a revelation. “Little explosions were going off in my head,” she told me. The archaeological evidence she and others had gathered made sense as a record of how humans changed their own environment.

Early foragers show signs of having moved wild plants away from their native habitats to have them close at hand, for example. As they watered the plants and protected them from herbivores, the plants adapted to their new environment. Weedy species also moved in and became crops of their own. Certain animals adapted to the environment as well, becoming dogs, cats and other domesticated species.

Gradually, the environment changed from sparse patches of wild plants to dense farm fields. That environment didn’t just drive the evolution of the plants. It also began to drive the cultural evolution of the farmers, too. Instead of wandering as nomads, they settled down in villages so that they could work the land around them. Society became more stable because children received an ecological inheritance from their parents. And so civilization began.

Niche construction is just one of many concepts from the Extended Evolutionary Synthesis that can help make sense of domestication, Zeder said. During her talk, she presented slide after slide of predictions it provides, about everything from the movements of early foragers to the pace of plant evolution.

“It felt like an infomercial for the Extended Evolutionary Synthesis,” Zeder told me later with a laugh. “But wait! You can get steak knives!”

The Return of Natural Selection

Among the members of the audience was a biologist named David Shuker. After listening quietly for a day and a half, the University of St Andrews researcher had had enough. At the end of a talk, he shot up his hand.

The talk had been given by Denis Noble, a physiologist with a mop of white hair and a blue blazer. Noble, who has spent most of his career at Oxford, said he started out as a traditional biologist, seeing genes as the ultimate cause of everything in the body. But in recent years he had switched his thinking. He spoke of the genome not as a blueprint for life but as a sensitive organ, detecting stress and rearranging itself to cope with challenges. “I’ve been on a long journey to this view,” Noble said.

To illustrate this new view, Noble discussed an assortment of recent experiments. One of them was published last year by a team at the University of Reading. They did an experiment on bacteria that swim by spinning their long tails.

First, the scientists cut a gene out of the bacteria’s DNA that’s essential for building tails. The researchers then dropped these tailless bacteria into a petri dish with a meager supply of food. Before long, the bacteria ate all the food in their immediate surroundings. If they couldn’t move, they died. In less than four days in these dire conditions, the bacteria were swimming again. On close inspection, the team found they were growing new tails.

“This strategy is to produce rapid evolutionary genome change in response to the unfavorable environment,” Noble declared to the audience. “It’s a self-maintaining system that enables a particular characteristic to occur independent of the DNA.”

That didn’t sound right to Shuker, and he was determined to challenge Noble after the applause died down.

“Could you comment at all on the mechanism underlying that discovery?” Shuker asked.

Noble stammered in reply. “The mechanism in general terms, I can, yes…” he said, and then started talking about networks and regulation and a desperate search for a solution to a crisis. “You’d have to go back to the original paper,” he then said.

While Noble was struggling to respond, Shuker went back to the paper on an iPad. And now he read the abstract in a booming voice.

“‘Our results demonstrate that natural selection can rapidly rewire regulatory networks,’” Shuker said. He put down the iPad. “So it’s a perfect, beautiful example of rapid neo-Darwinian evolution,” he declared.

Shuker distilled the feelings of a lot of skeptics I talked to at the conference. The high-flying rhetoric about a paradigm shift was, for the most part, unwarranted, they said. Nor were these skeptics limited to the peanut gallery. Several of them gave talks of their own.

“I think I’m expected to represent the Jurassic view of evolution,” said Douglas Futuyma when he got up to the podium. Futuyma is a soft-spoken biologist at Stony Brook University in New York and the author of a leading textbook on evolution. In other words, he was the target of many complaints during the meeting that textbooks paid little heed to things like epigenetics and plasticity. In effect, Futuyma had been invited to tell his colleagues why those concepts were ignored.

“We must recognize that the core principles of the Modern Synthesis are strong and well-supported,” Futuyma declared. Not only that, he added, but the kinds of biology being discussed at the Royal Society weren’t actually all that new. The architects of the Modern Synthesis were already talking about them over 50 years ago. And there’s been a lot of research guided by the Modern Synthesis to make sense of them.

Take plasticity. The genetic variations in an animal or a plant govern the range of forms into which organism can develop. Mutations can alter that range. And mathematical models of natural selection show how it can favor some kinds of plasticity over others.

If the Extended Evolutionary Synthesis was so superfluous, then why was it gaining enough attention to warrant a meeting at the Royal Society? Futuyma suggested that its appeal was emotional rather than scientific. It made life an active force rather than the passive vehicle of mutations.

“I think what we find emotionally or aesthetically more appealing is not the basis for science,” Futuyma said.

Still, he went out of his way to say that the kind of research described at the meeting could lead to some interesting insights about evolution. But those insights would only arise with some hard work that leads to hard data. “There have been enough essays and position papers,” he said.

Some members in the audience harangued Futuyma a bit. Other skeptical speakers sometimes got exasperated by arguments they felt didn’t make sense. But the meeting managed to reach its end on the third afternoon without fisticuffs.

“This is likely the first of many, many meetings,” Laland told me. In September, a consortium of scientists in Europe and the United States received $11 million in funding (including $8 million from the John Templeton Foundation) to run 22 studies on the Extended Evolutionary Synthesis.

Many of these studies will test predictions that have emerged from the synthesis in recent years. They will see, for example, if species that build their own environments — spider webs, wasp nests and so on — evolve into more species than ones that don’t. They will look at whether more plasticity allows species to adapt faster to new environments.

“It’s doing the research, which is what our critics are telling us to do,” said Laland. “Go find the evidence.”

Correction: An earlier version of this article misidentified the photograph of Andy Whiten as Gerd Müller.

This article was reprinted on TheAtlantic.com.

Large human brain evolved as a result of ‘sizing each other up’ (Science Daily)

Date:
August 12, 2016
Source:
Cardiff University
Summary:
Humans have evolved a disproportionately large brain as a result of sizing each other up in large cooperative social groups, researchers have proposed.

The brains of humans enlarged over time thanks to our sizing up the competition, say scientists. Credit: © danheighton / Fotolia

Humans have evolved a disproportionately large brain as a result of sizing each other up in large cooperative social groups, researchers have proposed.

A team led by computer scientists at Cardiff University suggest that the challenge of judging a person’s relative standing and deciding whether or not to cooperate with them has promoted the rapid expansion of human brain size over the last 2 million years.

In a study published in Scientific Reports, the team, which also includes leading evolutionary psychologist Professor Robin Dunbar from the University of Oxford, specifically found that evolution favors those who prefer to help out others who are at least as successful as themselves.

Lead author of the study Professor Roger Whitaker, from Cardiff University’s School of Computer Science and Informatics, said: “Our results suggest that the evolution of cooperation, which is key to a prosperous society, is intrinsically linked to the idea of social comparison — constantly sizing each up and making decisions as to whether we want to help them or not.

“We’ve shown that over time, evolution favors strategies to help those who are at least as successful as themselves.”

In their study, the team used computer modelling to run hundreds of thousands of simulations, or ‘donation games’, to unravel the complexities of decision-making strategies for simplified humans and to establish why certain types of behaviour among individuals begins to strengthen over time.

In each round of the donation game, two simulated players were randomly selected from the population. The first player then made a decision on whether or not they wanted to donate to the other player, based on how they judged their reputation. If the player chose to donate, they incurred a cost and the receiver was given a benefit. Each player’s reputation was then updated in light of their action, and another game was initiated.

Compared to other species, including our closest relatives, chimpanzees, the brain takes up much more body weight in human beings. Humans also have the largest cerebral cortex of all mammals, relative to the size of their brains. This area houses the cerebral hemispheres, which are responsible for higher functions like memory, communication and thinking.

The research team propose that making relative judgements through helping others has been influential for human survival, and that the complexity of constantly assessing individuals has been a sufficiently difficult task to promote the expansion of the brain over many generations of human reproduction.

Professor Robin Dunbar, who previously proposed the social brain hypothesis, said: “According to the social brain hypothesis, the disproportionately large brain size in humans exists as a consequence of humans evolving in large and complex social groups.

“Our new research reinforces this hypothesis and offers an insight into the way cooperation and reward may have been instrumental in driving brain evolution, suggesting that the challenge of assessing others could have contributed to the large brain size in humans.”

According to the team, the research could also have future implications in engineering, specifically where intelligent and autonomous machines need to decide how generous they should be towards each other during one-off interactions.

“The models we use can be executed as short algorithms called heuristics, allowing devices to make quick decisions about their cooperative behaviour,” Professor Whitaker said.

“New autonomous technologies, such as distributed wireless networks or driverless cars, will need to self-manage their behaviour but at the same time cooperate with others in their environment.”


Journal Reference:

  1. Roger M. Whitaker, Gualtiero B. Colombo, Stuart M. Allen, Robin I. M. Dunbar. A Dominant Social Comparison Heuristic Unites Alternative Mechanisms for the Evolution of Indirect ReciprocityScientific Reports, 2016; 6: 31459 DOI: 10.1038/srep31459

Is human behavior controlled by our genes? Richard Levins reviews ‘The Social Conquest of Earth’ (Climate & Capitalism)

“Failing to take class division into account is not simply a political bias. It also distorts how we look at human evolution as intrinsically bio-social and human biology as socialized biology.”

 

August 1, 2012

Edward O. Wilson. The Social Conquest of Earth. Liverwright Publishing, New York, 2012

reviewed by Richard Levins

In the 1970s, Edward O. Wilson, Richard Lewontin, Stephen Jay Gould and I were colleagues in Harvard’s new department of Organismic and Evolutionary Biology. In spite of our later divergences, I retain grateful memories of working in the field with Ed, turning over rocks, sharing beer, breaking open twigs, putting out bait (canned tuna fish) to attract the ants we were studying..

We were part of a group that hoped to jointly write and publish articles offering a common view of evolutionary science, but that collaboration was brief, largely because Lewontin and I strongly disagreed with Wilson’s Sociobiology.

Reductionism and Sociobiology

Although Wilson fought hard against the reduction of biology to the study of molecules, his holism stopped there. He came to promote the reduction of social and behavioral science to biology. In his view:

“Our lives are restrained by two laws of biology: all of life’s entities and processes are obedient to the laws of physics and chemistry; and all of life’s entities and processes have arisen through evolution and natural selection.” [Social Conquest, p. 287]

This is true as far as it goes but fails in two important ways.

First, it ignores the reciprocal feedback between levels. The biological creates the ensemble of molecules in the cell; the social alters the spectrum of molecules in the biosphere; biological activity creates the biosphere itself and the conditions for the maintenance of life.

Second, it doesn’t consider how the social level alters the biological: our biology is a socialized biology.

Higher (more inclusive) levels are indeed constrained by the laws at lower levels of organization, but they also have their own laws that emerge from the lower level yet are distinct and that also determine which chemical and physical entities are present in the organisms. In new contexts they operate differently.

Thus for example we, like a few other animals including bears, are omnivores. For some purposes such as comparing digestive systems that’s an adequate label. But we are omnivores of a special kind: we not only acquire food by predation, but we also producefood, turning the inedible into edible, the transitory into stored food. This has had such a profound effect on our lives that it is also legitimate to refer to us as something new, productivores.

The productivore mode of sustenance opens a whole new domain: the mode of production. Human societies have experienced different modes of production and ways to organize reproduction, each with its own dynamics, relations with the rest of nature, division into classes, and processes which restore or change it when it is disturbed.

The division of society into classes changes how natural selection works, who is exposed to what diseases, who eats and who doesn’t eat, who does the dishes, who must do physical work, how long we can expect to live. It is no longer possible to prescribe the direction of natural selection for the whole species.

So failing to take class division into account is not simply a political bias. It also distorts how we look at human evolution as intrinsically bio-social and human biology as socialized biology.

The opposite of the genetic determinism of sociobiology is not “the blank slate” view that claims that our biological natures were irrelevant to behavior and society. The question is, what about our animal heritage was relevant?

We all agree that we are animals; that as animals we need food; that we are terrestrial rather than aquatic animals; that we are mammals and therefore need a lot of food to support our high metabolic rates that maintain body temperature; that for part of our history we lived in trees and acquired characteristics adapted to that habitat, but came down from the trees with a dependence on vision, hands with padded fingers, and so on. We have big brains, with regions that have different major functions such as emotions, color vision, and language.

But beyond these general capacities, there is widespread disagreement about which behaviors or attitudes are expressions of brain structure. The amygdala is a locus of emotion, but does it tell us what to be angry or rejoice about? It is an ancient part of our brains, but has it not evolved in response to what the rest of the brain is doing? There is higher intellectual function in the cortex, but does it tell us what to think about?

Every part of an organism is the environment for the rest of the organism, setting the context for natural selection. In contrast to this fluid viewpoint, phrases such as “hard-wired” have become part of the pop vocabulary, applied promiscuously to all sorts of behaviors.

In a deeper sense, asking if something is heritable is a nonsense question. Heritability is always a comparison: how much of the difference between humans and chimps is heritable? What about the differences between ourselves and Neanderthals? Between nomads and farmers?

Social Conquest of Earth

The Social Conquest of Earth, Ed Wilson’s latest book, continues his interest in the “eusocial” animals – ants, bees and others that live in groups with overlapping generations and a division of labor that includes altruistic behavior. As the title shows. he also continues to use the terminology of conquest and domination, so that social animals “conquer” the earth, their abundance makes them “dominate.”

The problem that Wilson poses in this book is first, why did eusociality arise at all, and second, why is it so rare?

Wilson is at his best when discussing the more remote past, the origins of social behavior 220 million years ago for termites, 150 million years for ants, 70-80 million years for humble bees and honey bees.

But as he gets closer to humanity the reductionist biases that informed Sociobiology reassert themselves. Once again Wilson argues that brain architecture determines what people do socially – that war, aggression, morality, honor and hierarchy are part of “human nature.”

Rejecting kin selection

A major change, and one of the most satisfying parts of the book, is his rejection of kin selection as a motive force of social evolution, a theory he once defended strongly.

Kin selection assumed that natural selection acts on genes. A gene will be favored if it results in enhancing its own survival and reproduction, but it is not enough to look at the survival of the individual. If my brother and I each have 2 offspring, a shared gene would be doubled in the next generation. But if my brother sacrifices himself so that I might leave 5 offspring while he leaves none, our shared gene will increase 250%.

Therefore, argued the promoters of this theory, the fitness that natural selection increases has to be calculated over a whole set of kin, weighted by the closeness of their relationship. Mathematical formulations were developed to support this theory. Wilson found it attractive because it appeared to support sociobiology.

However, plausible inference is not enough to prove a theory. Empirical studies comparing different species or traits did not confirm the kin selection hypothesis, and a reexamination of its mathematical structure (such as the fuzziness of defining relatedness) showed that it could not account for the observed natural world. Wilson devotes a lot of space to refuting kin selection because of his previous support of it: it is a great example of scientific self-correction.

Does group selection explain social behaviour?

Wilson has now adopted another model in which the evolution of sociality is the result of opposing processes of ordinary individual selection acting within populations, and group selection acting between populations. He invokes this model account to for religion, morality, honor and other human behaviors.

He argues that individual selection promotes “selfishness” (that is, behavior that enhances individual survival) while group selection favors cooperative and “altruistic” behavior. The two forms of selection oppose each other, and that results in our mixed behaviors.

“We are an evolutionary chimera living on intelligence steered by the demands of animal instinct. This is the reason we are mindlessly dismantling the biosphere and with it, our own prospects for permanent existence.” [p.13]

But this simplistic reduction of environmental destruction to biology will not stand. Contrary to Wilson, the destruction of the biosphere is not “mindless.” It is the outcome of interactions in the noxious triad of greed, poverty, and ignorance, all produced by a socio-economic system that must expand to survive.

For Wilson, as for many environmentalists, the driver of ecological destruction is some generic “we,” who are all in the same boat. But since the emergence of classes after the adoption of agriculture some 8-10,000 years ago it is no longer appropriate to talk of a collective “we.”

The owners of the economy are willing to use up resources, pollute the environment, debase the quality of products, and undermine the health of the producers out of a kind of perverse economic rationality. They support their policies with theories such as climate change denial or doubting the toxicity of pesticides, and buttress it with legislation and court decisions.

Evolution and religion

The beginning and end of the book, a spirited critique of religion as possibly explaining human nature, is more straightforwardly materialist than the view supported by Stephen J. Gould, who argued that religion and science are separate magisteria that play equal roles in human wellbeing.

But Wilson’s use of evidence is selective.

For example, he argues that religion demands absolute belief from its followers – but this is true only of Christianity and Islam. Judaism lets you think what you want as long as you practice the prescribed rituals, Buddhism doesn’t care about deities or the afterlife.

Similarly he argues that creation myths are a product of evolution:

“Since paleolithic times … each tribe invented its own creation myths… No tribe could long survive without a creation myth… The creation myth is a Darwinian device for survival.” [p. 8]

But the ancient Israelites did not have an origin myth when they emerged as a people in the hills of Judea around 1250 B.C.E. Although it appears at the beginning of the Bible, the Israelites did not adapt the Book of Genesis from Babylonian mythology until four centuries after Deuteronomy was written, after they had survived 200 years as a tribal confederation, two kingdoms and the Assyrian and Babylonian conquests— by then the writing of scripture was a political act, not a “Darwinian device for survival.”

Biologizing war

In support of his biologizing of “traits,” Wilson reviews recent research that appears to a show a biological basis for the way people see and interpret color, for the incest taboo, and for the startle response – and then asserts that inherited traits include war, hierarchy, honor and such. Ignoring the role of social class, he views these as universal traits of human nature.

Consider war. Wilson claims that war reflects genes for group selection. “A soldier going into battle will benefit his country but he runs a higher risk of death than one who does not.” [p. 165]

But soldiers don’t initiate conflict. We know in our own times that those who decide to make war are not those who fight the wars – but, perhaps unfortunately, sterilizing the general staff of the Pentagon and of the CIA would not produce a more peaceful America.

The evidence against war as a biological imperative is strong. Willingness to fight is situational.

Group selection can’t explain why soldiers have to be coerced into fighting, why desertion is a major problem for generals and is severely punished, or why resistance to recruitment is a major problem of armies. In the present militarist USA, soldiers are driven to join up through unemployment and the promises of benefits such as learning skills and getting an education and self-improvement. No recruitment posters offer the opportunity to kill people as an inducement for signing up.

The high rates of surrender and desertion of Italian soldiers in World War II did not reflect any innate cowardice among Italians but a lack of fascist conviction. The very rarity of surrender by Japanese soldiers in the same war was not a testimony to greater bravery on the part of the Japanese but of the inculcated combination of nationalism and religion.

As the American people turned against the Vietnam war, increased desertions and the killing of officers by the soldiers reflected their rejection of the war.

The terrifying assaults of the Vikings during the middle ages bear no resemblance to the mellow Scandinavian culture of today, too short a time for natural selection to transform national character.

The attempt to make war an inherited trait favored by natural selection reflects the sexism that has been endemic in sociobiology. It assumes that local groups differed in their propensity for aggression and prowess in war. The victorious men carry off the women of the conquered settlements and incorporate them into their own communities. Therefore the new generation has been selected for greater military success among the men. But the women, coming from a defeated, weaker group, would bring with them their genes for lack of prowess, a selection for military weakness! Such a selection process would be self-negating.

Ethnocentrism

Wilson also considers ethnocentrism to be an inherited trait: group selection leads people to favor members of their own group and reject outsiders.

The problem is that the lines between groups vary under different circumstances. For example, in Spanish America, laws governing marriage included a large number of graded racial categories, while in North America there were usually just two. What’s more, the category definitions are far from permanent: at one time, the Irish were regarded as Black, and the whiteness of Jews was questioned.

Adoption, immigration, mergers of clans also confound any possible genetic basis for exclusion.

Hierarchy

Wilson draws on the work of Herbert Simon to argue that hierarchy is a result of human nature: there will always be rulers and ruled. His argument fails to distinguish between hierarchy and leadership.

There are other forms of organization possible besides hierarchy and chaos, including democratic control by the workers who elect the operational leadership. In some labor unions, leaders’ salaries are pegged to the median wage of the members. In University departments the chairmanship is often a rotating task that nobody really wants. When Argentine factory owners closed their plants during the recession, workers in fact seized control and ran them profitably despite police sieges.

Darwinian behavior?

Wilson argues that “social traits” evolved through Darwinian natural selection. Genes that promoted behaviors that helped the individual or group to survive were passed on; genes that weakened the individual or group were not. The tension between individual and group selection decided which traits would be part of our human nature.

But a plausible claim that a trait might be good for people is not enough to explain its origin and survival. A gene may become fixed in a population even if it is harmful, just by the random genetic changes that we know occur. Or a gene may be harmful but be dragged along by an advantageous gene close to it on the same chromosome.

Selection may act in different directions in different subpopulations, or in different habitats, or in differing environmental. Or the adaptive value of a gene may change with its prevalence or the distribution of ages in the population, itself a consequence of the environment and population heterogeneity.

For instance, Afro-Americans have a higher death rate from cancer than Euro-Americans. In part this reflects the carcinogenic environments they have been subjected to, but there is also a genetic factor. It is the combination of living conditions and genetics that causes higher mortality rates.

* * *

Obviously I am not arguing that evolution doesn’t happen. The point is that we need a much better argument than just a claim that some genotype might be beneficial. And we need a much more rigorous understanding of the differences and linkages between the biological and social components of humanity’s nature. Just calling some social behavior a “trait” does not make it heritable.

In a book that attempts such a wide-ranging panorama of human evolution, there are bound to be errors. But the errors in The Social Conquest of Earth form a pattern: they reduce social issues to biology, and they insist on our evolutionary continuity with other animals while ignoring the radical discontinuity that made us productivores and divided us into classes.

The surprising links between faith and evolution and climate denial — charted (The Washington Post)

 May 20, 2015

For a long time, we’ve been having a pretty confused discussion about the relationship between religious beliefs and the rejection of science — and especially its two most prominent U.S. incarnations, evolution denial and climate change denial.

At one extreme is the position that science denial is somehow deeply or fundamentally religion’s fault. But this neglects the wide diversity of views about science across faiths and denominations — and even across individuals of the same faith or denomination — not all of which are anti-climate science, or anti-evolution.

At the other extreme, meanwhile, is the view that religion has no conflict with science at all. But that can’t be right either: Though the conflict between the two may not be fundamental or necessary in all cases, it is pretty clear that the main motive for evolution denial is, indeed, a perceived conflict with faith (not to mention various aspects of human cognition that just make accepting evolution very hard for many people).

The main driver of climate science rejection, however, appears to be a free market ideology — which is tough to characterize as religious in nature. Nonetheless, it has often been observed (including by me) that evolution denial and climate science rejection often seem to overlap, at least to an extent.

[Pope Francis has given the climate movement just what it needed: faith]

And there does seem to be at least some tie between faith and climate science doubt. Research by Yale’s Dan Kahan, for instance, found a modest correlation between religiosity and less worry about climate change. Meanwhile, a 2013 study in Political Science Quarterly found that “believers in Christian end-times theology are less likely to support policies designed to curb global warming than are other Americans.”

So how do we make sense of this complex brew?

Josh Rosenau, an evolutionary biologist who works for the National Center for Science Education — which champions both evolutionary science and climate science teaching in schools — has just created a chart that, no matter what you think of the relationship between science and religion, will give you plenty to talk about.

Crunching data from the 2007 incarnation of a massive Pew survey of American religious beliefs, Rosenau plotted different U.S. faiths and denominations based on their members’ views about both the reality of specifically human evolution, and also how much they favor “stricter environmental laws and regulations.” And this was the result (click to enlarge):

As Rosenau notes, in the figure above, “The circle sizes are scaled so that their areas are in proportion to the relative population sizes in Pew’s massive sample (nearly 36,000 people!).” And as you can see, while at the top right atheists, agnostics, Buddhists, non-Orthodox Jews and others strongly accept evolution and environmental rules, at the bottom left Southern Baptists, Pentecostals and other more conservative leaning faiths are just as skeptical of both.

Obviously, it is important to emphasize that a given individual, of any faith, could be anywhere on the chart above — it’s just that this is where the denominations as a whole seemed to fall out, based on Rosenau’s analysis (which itself mirrors prior analyses of the political alignments of U.S. faiths and denominations by political scientist and Religion News Service blogger Tobin Grant).

Reached by phone Tuesday, Rosenau (whom I’ve known for a long time from the community of bloggers about science and the environment) seemed to be still trying to fully understand the implications of the figure he’d created. “People seemed to like it,” he said. “I think some people are finding hope in it” — hope, specifically, that there is a way out of seemingly unending science versus religion spats.

Here are some of Rosenau’s other conclusions from the exercise, from his blog post introducing the chart:

First, look at all those groups whose members support evolution. There are way more of them than there are of the creationist groups, and those circles are bigger. We need to get more of the pro-evolution religious out of the closet.

Second, look at all those religious groups whose members support climate change action. Catholics fall a bit below the zero line on average, but I have to suspect that the forthcoming papal encyclical on the environment will shake that up.

[Our new pro-science pontiff: Pope Francis on climate change, evolution, and the Big Bang]

Rosenau also remarks on the striking fact that for the large bulk of religions and religious denominations, as support for evolution increases, so does support for tougher environmental rules (and vice versa). The two appear to be closely related.

So what can that mean?

Rosenau told me he was still trying to work that out — still playing with the data and new analyses to try to understand it.

One possible way of interpreting the figure is that as with political parties themselves, people at least partially self-sort into faiths or denominations that seem more consonant with their own worldviews. And thus, a cluster of issue stances may travel alongside these choices of affiliation. “People are choosing what religion they want to associate with,” suggested Rosenau. “If people feel alienated from a church, they’re switching.”

There may also be a substantive point here that links together the ideas. A view of the world that thinks of human beings as having evolved, as being part of the natural world and having emerged through the same process as other organisms, may also be related to a manner of thinking that puts great overall emphasis on the value of nature and one’s connectedness with it.

In any case, while the pattern above may require more analysis, one clear punchline of the figure is that it really doesn’t make sense to say that religion is at war with science. You can say that for some people, religion is clearly linked to less science acceptance — especially on evolution. But for others, clearly, religion presents no hurdle at all.

I would also agree that these data reinforce the idea that the pope’s coming encyclical on the environment could really shake matters up. Catholics are the biggest bubble in the chart above, and they’re right in the middle of the pack on the environment.

The pope, incidentally, also appears to accept evolution.

Chimpanzés caçadores dão pistas sobre os primeiros humanos (El País)

Primatas que usam lanças podem fornecer indícios sobre origem das sociedades humanas

 12 MAY 2015 – 18:14 BRT

Um velho chimpanzé bebe água em um lago, em Fongoli, no Senegal. / FRANS LANTING

Na quente savana senegalesa se encontra o único grupo de chimpanzés que usa lanças para caçar animais com os quais se alimenta. Um ou outro grupo de chimpanzés foi visto portando ferramentas para a captura de pequenos mamíferos, mas esses, na comunidade de Fongoli, caçam regularmente usando ramos afiados. Esse modo de conseguir alimento é um uso cultural consolidado para esse grupo de chimpanzés.

Além dessa inovação tecnológica, em Fongoli ocorre também uma novidade social que os distingue dos demais chimpanzés estudados na África: há mais tolerância, maior paridade dos sexos na caça e os machos mais corpulentos não passam com tanta frequência por cima dos interesses dos demais, valendo-se de sua força. Para os pesquisadores que vêm observando esse comportamento há uma década esses usos poderiam, além disso, oferecer pistas sobre a evolução dos ancestrais humanos.

“São a única população não humana conhecida que caça vertebrados com ferramentas de forma sistemática, por isso constituem uma fonte importante para a hipótese sobre o comportamento dos primeiros hominídeos, com base na analogia”, explicam os pesquisadores do estudo no qual formularam suas conclusões depois de dez anos observando as caçadas de Fongoli. Esse grupo, liderado pela antropóloga Jill Pruetz, considera que esses animais são um bom exemplo do que pode ser a origem dos primeiros primatas eretos sobre duas patas.

Os machos mais fortes dessa comunidade respeitam as fêmeas na caça

Na sociedade Fongoli as fêmeas realizam exatamente a metade das caçadas com lança. Graças à inovação tecnológica que representa a conversão de galhos em pequenas lanças com as quais se ajudam para caçar galagos – pequenos macacos muito comuns nesse entorno –, as fêmeas conseguem certa independência alimentar. Na comunidade de Gombe, que durante muitos anos foi estudada por Jane Goodall, os machos arcam com cerca de 90% do total das presas; em Fongoli, somente 70%. Além disso, em outros grupos de chimpanzés os machos mais fortes roubam uma de cada quatro presas caçadas pelas fêmeas (sem ferramentas): em Fongoli, apenas 5%.

Uma fêmea de chimpanzé apanha e examina um galho que usará para capturar sua presa. / J. PRUETZ

“Em Fongoli, quando uma fêmea ou um macho de baixo escalão captura uma presa, permitem que ele fique com ela e a coma. Em outros lugares, o macho alfa ou outro macho dominante costuma tomar-lhe a presa. Assim, as fêmeas obtêm pouco benefício da caça, se outro chimpanzé lhe tira sua presa”, afirma Pruetz. Ou seja, o respeito dos machos de Fongoli pelas presas obtidas por suas companheiras serviria de incentivo para que elas se decidam a ir à caça com mais frequência do que as de outras comunidades. Durante esses anos de observação, praticamente todos os chimpanzés do grupo – cerca de 30 indivíduos – caçaram com ferramentas,

O clima seco faz com que os macacos mais acessíveis em Fongoli sejam os pequenos galagos, e não os colobos vermelhos – os preferidos dos chimpanzés em outros lugares da África –, que são maiores e difíceis de capturar por outros que não sejam os machos mais rápidos e corpulentos. Quase todos os episódios de caça com lanças observados (três centenas) se deram nos meses úmidos, nos quais outras fontes de alimento são escassas.

A savana senegalesa, com poucas árvores, é um ecossistema que tem uma importante semelhança com o cenário em que evoluíram os ancestrais humanos. Ao contrário de outras comunidades africanas, os chimpanzés de Fongoli passam a maior parte do tempo no chão, e não entre os galhos. A excepcional forma de caça de Fongoli leva os pesquisadores a sugerir em seu estudo que os primeiros hominídeos provavelmente intensificaram o uso de ferramentas tecnológicas para superar as pressões ambientais, e que eram até mesmo “suficientemente sofisticados a ponto de aperfeiçoar ferramentas de caça”.

“Sabemos que o entorno tem um impacto importante no comportamento dos chimpanzés”, afirma o primatólogo Joseph Call, do Instituto Max Planck. “A distribuição das árvores determina o tipo de caça: onde a vegetação é mais frondosa, a caçada é mais cooperativa em relação a outros entornos nos quais é mais fácil seguir a presa, e eles são mais individualistas”, assinala Call.

No entanto, Call põe em dúvida que essas práticas de Fongoli possam ser consideradas caçadas com lança propriamente ditas, já que para ele lembram mais a captura de formigas e cupins usando palitos, algo mais comum entre os primatas. “A definição de caça que os pesquisadores estabelecem em seu estudo não se distingue muito do que fazem colocando um raminho em um orifício para conseguir insetos para comer”, diz Call. Os chimpanzés de Fongoli cutucam com paus os galagos quando eles se escondem em cavidades das árvores para forçá-los a sair e, uma vez fora, lhes arrancam a cabeça com uma mordida. “É algo que fica entre uma coisa e a outra”, argumenta.

Esses antropólogos acreditam que o achado permite pensar que os primeiros hominídeos eretos também usavam lanças

Pruetz responde a esse tipo de crítica dizendo que se trata de uma estratégia para evitar que o macaco os morda ou escape, uma situação muito diferente daquela de colocar um galho em um orifício para capturar bichos. Se for o mesmo, argumentam Pruetz e seus colegas, a pergunta é “por que os chimpanzés de outros grupos não caçam mais”.

Além do caso particular, nem sequer está encerrado o debate sobre se os chimpanzés devem ser considerados modelos do que foram os ancestrais humanos. “Temos de levar em conta que o bonobo não faz nada disso e é tão próximo de nós como o chimpanzé”, defende Call. “Pegamos o chimpanzé por que nos cai bem para assinalar determinadas influências comuns. É preciso ter muito cuidado e não pesquisar a espécie dependendo do que queiramos encontrar”, propõe.

An evolutionary approach reveals new clues toward understanding the roots of schizophrenia (AAAS)

24-FEB-2015

MOLECULAR BIOLOGY AND EVOLUTION (OXFORD UNIVERSITY PRESS)

Is mental illness simply the evolutionary toll humans have to pay in return for our unique and superior cognitive abilities when compared to all other species? But if so, why have often debilitating illnesses like schizophrenia persisted throughout human evolutionary history when the affects can be quite negative on an individual’s chances of survival or reproductive success?

In a new study appearing in Molecular Biology and Evolution, Mount Sinai researcher Joel Dudley has led a new study that suggests that the very changes specific to human evolution may have come at a cost, contributing to the genetic architecture underlying schizophrenia traits in modern humans.

“We were intrigued by the fact that unlike many other mental traits, schizophrenia traits have not been observed in species other than humans, and schizophrenia has interesting and complex relationships with human intelligence,” said Dr. Joel Dudley, who led the study along with Dr. Panos Roussos. “The rapid increase in genomic data sequenced from large schizophrenia patient cohorts enabled us to investigate the molecular evolutionary history of schizophrenia in sophisticated new ways.”

The team examined a link between these regions, and human-specific evolution, in genomic segments called human accelerated regions, or HARs. HARs are short signposts in the genome that are conserved among non-human species but experienced faster mutation rates in humans. Thus, these regions, which are thought to control the level of gene expression, but not mutate the gene itself, may be an underexplored area of mental illness research.

The team’s research is the first study to sift through the human genome and identify a shared pattern between the location of HARs and recently identified schizophrenia gene loci. To perform their work, they utilized a recently completed, largest schizophrenia study of its kind, the Psychiatric Genomics Consortium (PGC), which included 36,989 schizophrenia cases and 113,075 controls. It is the largest genome-wide association study ever performed on any psychiatric disease.

They found that the schizophrenic loci were most strongly associated in genomic regions near the HARs that are conserved in non-human primates, and these HAR-associated schizophrenic loci are found to be under stronger evolutionary selective pressure when compared with other schizophrenic loci. Furthermore, these regions controlled genes that were expressed only in the prefrontal cortex of the brain, indicating that HARs may play an important role in regulating genes found to be linked to schizophrenia. They specifically found the greatest correlation between HAR-associated schizophrenic loci and genes controlling the expression of the neurotransmitter GABA, brain development, synaptic formations, adhesion and signaling molecules.

Their new evolutionary approach provides new insights into schizophrenia, and genomic targets to prioritize future studies and drug development targets. In addition, there are important new avenues to explore the roles of HARs in other mental diseases such as autism or bipolar disorder.

The Snapchat and The Platypus (Medium)

Scissor-testing A New Branch of the Mobile Evolutionary Tree

Andrew McLaughlin

The British Museum still has the first platypus sent back to Europe from Australia, by Captain John Hunter in 1799. There are scissor marks on its duck-bill.

The first platypus specimen studied by European scientists, at the British Museum.

That’s because George Shaw, the first scientist who studied the astonishing specimen, was pretty sure it was a hoax, sewn together by pranksters or profiteers. With its webbed feet, furry pelt, venomous claw, and ducky beak, it was too freakish to be believed; moreover, London society had lately been thrilled, then crestfallen, by a wave of Franken-mermaids and other concocted exotica hawked by foreign sailors. So Shaw’s first move upon examining the platypus was to reach for his scissors, to uncover what kind of clever stitches bound the amalgamation together.

First published illustrations of a platypus, by George Shaw, “The Duck-Billed Platypus,” Naturalist’s Miscellany, Vol. X (1799).

Finding that the platypus was held together by flesh, not thread, Shaw stopped snipping and starting measuring, and marveling. He published a dutiful summary of his anatomical observations, together with field notes from Australia, in the impossibly well-named Naturalist’s Miscellany. Even with the benefit of several additional, later-arriving specimens, he wrote that it was “impossible not to entertain some doubts as to the genuine nature of the animal, and to surmise that there might have been practised some arts of deception in its structure.”

Which brings me to Snapchat.

When a certain kind of person — OK, an older person, where “old” equals 24— first encounters Snapchat, the reaction is typically some mixture of mystification, disbelief, and annoyance. For people who have gotten used to the dominant evolved anatomies of mobile apps, Snapchat seems like an odd and improbable creature.

A typical sentiment:

Or, as the 32-year-old Will Oremus put it in a brilliant and entertaining screed: “Is Snapchat Really Confusing, Or Am I Just Old?

A quick cruise through the app reveals why people born before the dawn of Clinton Administration react so strongly to it: Snapchat’s UI is really different from what we’re used to. What we’re used to is desktop software and its lineal descendants, with their predictably-located upper-margin drop-down menus, scrollable windows and swappable tabs, and logo-bearing application icons. On our mobile devices, designers have forged comfortingly similar UI elements, ever-so-slightly tweaked to work on smaller screens: scrollable feeds, sliding drawers with logically stacked navigation and option menus, all signaled by a homescreen hamburger icon.

Here are some of the ways Snapchat is different:

  • The app opens in camera mode. You don’t start with a social feed like Facebook, Twitter, LinkedIn, or Instagram, an editorial content feed like Digg, Buzzfeed, or the New York Times, a list of friends like Google Hangouts or Line, or a chronology of recent messages like FaceTime, Skype, or Slack. Instead, you start with whatever your phone’s camera is currently aimed at. Snapchat believes that you (should) want to create something — a photo, a short video— for immediate sharing. Snapchat is designed for you to create first, consume later.
  • There is no options menu. You have to navigate around the app without the crutch of a menu adorned with actual words that spell out what you can do and where you can go. But wait, you cry, there is (sometimes) a hamburger icon right there on the homescreen! Only it doesn’t do what you expect. Tapping the hamburger takes you to Snapchat Stories, a sort of expansive, broadcast-like version of the Snapchat snap. It doesn’t open a sliding drawer with a soothing hierarchical options menu. In Snapchat, navigation is done directly, via left/right/up/down thumb slides, supplemented by a handful of redundant touchable icons. People who are used to tapping well-labeled menu options are often baffled by Snapchat; but conversely, it will feel natural to someone whose first software experiences were on a mobile device, rather than a desktop.
  • Snapchat uses icons that change shape and color to signal different things. For example, a solid arrow is a sent snap (image or video); red if without audio, purple if with audio, and blue if a text chat only. The arrow becomes hollow once a friend has opened it. A solid square is a received snap or chat, with the same variations of color and hollowness. There are other icons that alert you when a friend has replayed or taken a screenshot of your snap. It’s not a complicated system, but it is esoteric and native to Snapchat; nothing about it is self-evident to new users.
  • Snapchat doesn’t pester you to keep connecting to more people.Adding friends in Snapchat is bizarrely cumbersome. If you’re used to traditional social apps, your first move will be tap on “Add Friends” (if you can find it), import your phone’s contacts database, and then squint through the entire list, name by name, to see which ones are on Snapchat and manually add them. It’s a huge pain if you have a lot of contacts. But Snapchat conversely makes it super-easy to add a friend when you are physically together by giving you a personally-encoded, QR-like Ghostface Chillah icon that can be snapped by a friend to add you. Notably, when you first set up Snapchat, you find that you can’t import your social graph from Facebook, Twitter, Google, etc. Snapchat draws solely on your phone’s contacts database. Though to some measure driven by necessity (at some point between the introduction of Pinterest’s “Add All My Facebook Friends” feature and the launch of Snapchat, Facebook started blocking new social services from using its social graph to kickstart theirs) Snapchat’s use of the phone’s contacts database reflects its emphasis on intimate, private, person-to-person communications with people you already know (or just met). It also shows Snapchat’s determination not to be dependent on other companies for core elements of its offerings.

So Snapchat’s user interface really is different, and different in ways that turn off a lot of people habituated to the dominant mobile design vocabulary, descended from desktop applications. And yet, Snapchat’s been getting hugely popular, with somebody.

Like any social or communications application, Snapchat has grown through real-world social pathways: its users tell their friends to get on it. If your friends or colleagues don’t use it, you won’t find much value in it. As a result, social and communications services like Snapchat, WhatsApp, WeChat, KakaoTalk, Viber, Line, Kik, etc., can saturate some discrete user clusters (e.g., U.S. Hispanic teens living in Southern California, Brooklyn-based social media junkies, female Korean professionals, etc.) but be almost unknown in others.

In the U.S., for example, Snapchat’s user cohort is overwhelming young — younger than any scaled social app we’ve seen before.

From Business Insider, July 30, 2014, http://www.businessinsider.com/a-primer-on-snapchat-and-its-demographics-2014-6

But the fact that Snapchat has become hugely popular with a wide swath of 12-to-24 year-old Americans doesn’t answer Will Oremus’s basic question. At the risk of stretching my metaphor past the breaking point, it doesn’t tell you whether Snapchat is a platypus (an isolated and precarious evolutionary adaptation well-suited to a specific subcontinental ecology), a fake mermaid (an apparent evolutionary advance that falls apart upon close inspection), or something more like a killer whale (a seemingly unlikely but wildly successful branch of the mammalian tree that has become an apex predator prowling every ocean and climate).


A few weeks ago, my betaworks partners and I found ourselves arguing about Snapchat, the merits of its app interface, and the trajectory of its future path. To get some practical data, and to understand Snapchat more thoroughly, we decided to commit to it, hard, for a week. And then to do the same for other fast-rising communications apps.

To reach meaningful scale, we enforced a herd migration among betaworkers. Starting two weeks ago, we announced that all intra-betaworks communications had to happen via Snapchat. If you wanted to reach us, you had to use Snapchat.

The result has been a scissor-test of Snapchat. We still ended up with conflicting opinions about whether Snapchat is poorly or brilliantly designed (or both). But we all agreed that the experience is more intimate, more private, and more creativity-sparking than we had previously understood. (And I learned the hard way how Snapchat punishes procrastination: one morning, my partner Sam sent me a couple of questions about a pending deal; I quickly scanned them while out on the sidewalk across town; when I returned to the office and opened the app to compose a response, Sam’s chats had disappeared and I couldn’t remember what the questions were.)

There’s one part of Snapchat, though, that really does seem to be grafted on like a fake duck-bill. Snapchat Discover is a new section of the app where big media companies like CNN, ESPN, People, Cosmopolitan, and the Daily Mail post slickly-produced packages that have as much in common with the casual, rough-hewn, intimate, person-to-person snap as Air Force One has with a homemade kite. Snapchat Discover is broadcast, not interpersonal; professional, not amateur; branded, not hacked. Snapchat’s ability to drive attention may ultimately make its Discover platform a viable (native, mobile, short-form) alternative to TV. But for now, it feels like an amphibian limb sutured onto a mammalian torso.

Looking at Snapchat Discover from the perspective of Digg, as a potential someday distribution platform, I can see why Buzzfeed declined to participate, at least for now.


My conclusion from the scissor-test is that Snapchat really is a new and promising branch of the mobile evolutionary tree, but burdened with at least one surgically dubious addition.

The Snapchat week was so much fun, we’re moving on. Last week, we all dogpiled onto Line. This week, WeChat. Next up, in some order, will be WhatsAppKikViberKakaoTalk, and so on.

More test results to come.

SBPC envia carta a deputados contra o ensino do criacionismo em escolas (Ascom SBPC)

A entidade quer que permaneça no ensino o princípio da laicidade e liberdade de crença garantidos pela Constituição federal 

A Sociedade Brasileira para o Progresso da Ciência (SBPC) enviou aos deputados federais uma carta solicitando que o Projeto de Lei 8099/2014, de deputado Marco Feliciano (PSC/SP), que propõe a inserção de conteúdos sobre criacionismo na grade curricular das Redes Pública e Privada de Ensino, e seu apensado ao PL 309/2011, de autoria do mesmo deputado, que “altera o Art. 33 da Lei nº 9.394, de 20 de dezembro de 1996, para dispor sobre a obrigatoriedade do ensino religioso nas redes públicas de ensino do país”, sejam rejeitados e arquivados. Segundo a SBPC, isso é necessário para se manter o princípio da laicidade e liberdade de crença garantidos pela Constituição federal, bem como o não comprometimento do ensino das Ciências aos alunos.

Veja a carta na íntegra em:

http://jcnoticias.jornaldaciencia.org.br/wp-content/uploads/2014/12/Ofício122PLcriacionismo.pdf

(Ascom SBPC)

*   *   *

Em defesa da Ciência

O leitor Clécio Fernando Klitzke.  envia carta à SBPC onde comenta as ameaças e os retrocessos sobre o que é a Ciência, e o que são dogmas como o criacionismo e o “design inteligente”

Li a matéria no sítio de internet da SBPC a respeito da posição da ABRAPEC e SBEnBIO sobre o projeto de lei que tenta obrigar o ensino de criacionismo nas escolas brasileiras.

Não bastasse o desserviço de alguns políticos evangélicos a respeito do que é ciência e conhecimento científico, nos deparamos também com movimentos organizados no próprio meio acadêmico, visando a deturpação do que seja ciência e teoria científica.

Recentemente tivemos no país um evento neo criacionista onde foi fundada a sociedade brasileira do design inteligente. Mais triste é constatar que páginas que divulgam ciência também divulgam eventos criacionistas.

Por exemplo:

http://www.visaociencia.com.br/1-congresso-brasileiro-de-design-inteligente-promove-debate-historico/

Não bastasse isso, a própria universidade pública abre espaço para essas ideias medievais, como exemplo:

http://www.ufal.edu.br/noticias/2014/11/teoria-do-design-inteligente-e-tema-de-debate-sobre-a-origem-da-vida

Esses profissionais esqueceram o que é ciência e objeto de pesquisa científica e se deixaram levar pela fé religiosa e seus dogmas. Agora apresentam o criacionismo travestido de teoria científica, com novo nome e roupagem, a tal da teoria do design inteligente, quem nem teoria é.

Não bastassem os políticos, temos professores e pesquisadores que também sonham com o ensino de criacionismo nas escolas e universidades.

Seria muito útil se a SBPC também divulgasse um manifesto em defesa da ciência e do conhecimento científico, se opondo a essas tentativas de incluir criacionismo como conhecimento científico.

Em 2012 a Sociedade Brasileira de Genética publicou um manifesto em seu sítio de internet.

http://sbg.org.br/2012/08/manifesto-da-sbg-sobre-ciencia-e-criacionismo/

Seria interessante reforçar para a sociedade que criacionismo é crença, não é ciência e que cientistas que se deixam levar por suas crenças prestam um desserviço ao conhecimento. O mais apavorante é que temos até mesmo membro da Academia Brasileira de Ciências defendendo o criacionismo como conhecimento científico e liderando esse movimento no Brasil.

Clécio Fernando Klitzke é Bacharel em Ciências Biológicas, Mestre em Ecologia, Doutor em Ciências (Química Orgânica).

A Magisterial Synthesis Of Apes And Human Evolution (Forbes)

11/23/2014 @ 10:31AM By John Farrell

There are books to read from cover to cover in a week or two, and then there are the ones you dip into over and over again, because they aren’t books so much as encyclopedias.

Russell H. Tuttle’s Apes and Human Evolution is one of these. Like the late Stephen Jay Gould’s magisterial Structure of Evolutionary Theory, Tuttle’s tome is a grand synthesis of all the latest research and data about apes and their relation to us.

Tuttle is Professor of Anthropology, Evolutionary Biology, History of Science and Medicine and the College at the University of Chicago.

Tuttle believes that bipedalism preceded the development of the brain in early humans –and was likely something inherited from smaller apes already used to using their feet to move laterally along branches in trees. Although chimpanzees and bonobos are our closest relatives on the evolutionary tree, they do not represent in their own locomotion good proto-models of what led to human upright posture and walking.

While the book does not need to be read in any particular order, the first two chapters set the stage and the terminology for the rest of Apes and Human Evolution, which consists of five parts, totaling 13 dense chapters. A glossary of terms would have helped, but it’s not too much of a distraction to look up the specialist terms Tuttle introduces in these opening sections.

But lest you think it is intended chiefly for colleagues in the fields of anthropology and evolutionary biology, Tuttle’s style throughout is crisp and often witty. (The chapter on the development of human bipedalism, for example, is called ‘How to Achieve an Erection’.)

Professor Russell H. Tuttle, University of Chicago. Image courtesy of Phys.org.

The opening chapter, ‘Mongrel Models and Seductive Scenarios of Human Evolution’ discusses several hypotheses of human origins, some of which Tuttle argues are biased and which in recent years more detailed study of apes has refuted.

He has a low opinion, for example, of the idea that humans are in essence a species of ‘killer apes’, a notion that gained popularity during the last century. “The views of Charles Darwin,” he writes, “are restrained in comparison with the speculations by the advocates of killer ape scenarios, which flourished for several decades after the horrors of World War I and World War II.”

Darwin portrayed early man (his term) as having “sprung from some comparatively weak creature,” who was not speedy and who lacked natural bodily defenses, namely, formidable canine teeth. Consequently, this bipedal creature was stimulated to use his intellectual powers to make weapons for defense and hunting and to cooperate with “his fellow-men”.

What distinguishes humans among the approximately 400 extant species of primates? In Tuttle’s view, a constellation of morphological and behavioral characteristics, some of which only can be traced precisely through the fossil and archeological records.

Obligate terrestrial bipedalism, precision-gripping hands, reduced teeth and jaws, and ballooned brains can be identified if fossils are complete enough in the skeletal regions under study. Archeological artifacts and features can indicate the presence of tool use and manufacture, control of fire, fabricated shelters, bodily ornamentation, mortuary practice, plastic and graphic arts, and other indications of cognitive skills and culture.

There are also the features that can’t be easily found in fossils or the archeological records, primarily social: cooperation, the ability to enlist new members from outside the immediate community of hominids.

Space does not allow a detailed review of each chapter, summaries of which you can find here. But in the final part, ‘What Makes Us Human?’, Tuttle reveals more of his own philosophical reflections on the matter.

One passage that struck me, for example, occurs in the sub-section, ‘What is More Real: God or Race?’

I believe that God is an ever-increasing collective emergent of the love of all beings past, present and future, but this cannot be proven by available scientific methods of experimentation or controlled comparison. In contrast, the belief in race, in the sense of biological subspecies of Homo Sapiens, lacks a tangible basis; indeed, it has been proven unsupportable genomically, behaviorally, and phenotypically.

Individuals and political groups have manipulated both God and race for nefarious purposes, but actions rooted in the human capacity to affiliate with non-kin, to cooperate, and especially to unite in love and respect for the agency of others has given rise to a variety of constructive social codes that facilitate intragroup and extensive intergroup harmony and mitigate disruptive personal and social behavior.

Whereas scientists possess the means to eliminate belief in human races, they lack the means to eradicate belief in God, and frankly they are probably wasting time and treasure on the exercise.

There’s an optimism here I found somewhat reminiscent of the Jesuit paleontologist Teilhard de Chardin, who had a very goal-oriented view of humanity and its role in cosmic evolution.

I could’t resist asking Tuttle whether Teilhard’s writings had any influence on his own thought as he embarked on his career in the 1960s. This was around the time that Teilhard’s writings were becoming most influential.

“Quite the contrary,” Tuttle replied in an email. “I thought Phenomenon of Man was rubbish. Father Teilhard wanted to be an evolutionary biologist while not giving up God. He did a shoddy job of reconciling deep religious belief with evolutionary biology…for one, he was an orthogenecist [i.e., he believed in progressive, directional evolution, toward a universal goal].”

“I cannot see a reconciliation of the two realms,” Tuttle added. “I believe in the power of love which some or many see as an aspect of God. But I do not think  there is a celestial, etherial being that is interested in us or that makes good or bad things happen.”

Tuttle elaborated on this in a recent review he wrote for the American Journal of Psychology: “As a Christian participant observer into my late teens, followed by two decades attempting to be an atheist, and then participation in the music ministry at a wide variety of churches over the past 30 years, I aver that the bonding of congregations based on love of God and one another are substantive enough to withstand the sarcastic remarks and mockery of professed atheists who command notable space in print media and on the airways.”

Apes and Human Evolution is also available in Kindle Edition. But given the slight difference in price, I recommend getting the print edition.

Of gods and men: Societies living in harsh environments are more likely to believe in moralizing gods (Science Daily)

Date: November 10, 2014

Source: National Evolutionary Synthesis Center (NESCent)

Summary: New research finds that cultures living in harsher ecosystems with limited resources are more prone to a belief in moralizing, high gods. The results indicate that other cross-disciplinary factors, including as political complexity, also influence this belief.


Just as physical adaptations help populations prosper in inhospitable habitats, belief in moralizing, high gods might be similarly advantageous for human cultures in poorer environments. A new study from the National Evolutionary Synthesis Center (NESCent) suggests that societies with less access to food and water are more likely to believe in these types of deities.

“When life is tough or when it’s uncertain, people believe in big gods,” says Russell Gray, a professor at the University of Auckland and a founding director of the Max Planck Institute for History and the Sciences in Jena, Germany. “Prosocial behavior maybe helps people do well in harsh or unpredictable environments.”

Gray and his coauthors found a strong correlation between belief in high gods who enforce a moral code and other societal characteristics. Political complexity–namely a social hierarchy beyond the local community– and the practice of animal husbandry were both strongly associated with a belief in moralizing gods.

The emergence of religion has long been explained as a result of either culture or environmental factors but not both. The new findings imply that complex practices and characteristics thought to be exclusive to humans arise from a medley of ecological, historical, and cultural variables.

“When researchers discuss the forces that shaped human history, there is considerable disagreement as to whether our behavior is primarily determined by culture or by the environment,” says primary author Carlos Botero, a researcher at the Initiative for Biological Complexity at North Carolina State University. “We wanted to throw away all preconceived notions regarding these processes and look at all the potential drivers together to see how different aspects of the human experience may have contributed to the behavioral patterns we see today.”

The paper, which is now available online, will be published in an upcoming issue of the Proceedings of the National Academies of Science. To study variables associated with the environment, history, and culture, the research team included experts in biology, ecology, linguistics, anthropology, and even religious studies. The senior author, Gray, studies the intersection of psychology and linguistics, while Botero, an evolutionary ecologist, has examined coordinated behaviors in birds.

This study began with a NESCent working group that explored the evolution of human cultures. On a whim, Botero plotted ethnographic data of societies that believe in moralizing, high gods and found that their global distribution is quite similar to a map of cooperative breeding in birds. The parallels between the two suggested that ecological factors must play a part. Furthermore, recent research has supported a connection between a belief in moralizing gods and group cooperation. However, prior to this study, evidence supporting a relationship between such beliefs and the environment was elusive.

“A lot of evolutionists have been busy trying to bang religion on the head. I think the challenge is to explain it,” Gray says.

“Although some aspects of religion appear maladaptive, the near universal prevalence of religion suggests that there’s got to be some adaptive value and by looking at how these things vary ecologically, we get some insight.”

Botero, Gray, and their coauthors used historical, social, and ecological data for 583 societies to illustrate the multifaceted relationship between belief in moralizing, high gods and external variables. Whereas previous research relied on rough estimates of ecological conditions, this study used high-resolution global datasets for variables like plant growth, precipitation, and temperature. The team also mined the Ethnographic Atlas– an electronic database of more than a thousand societies from the 20th century– for geographic coordinates and sociological data including the presence of religious beliefs, agriculture, and animal husbandry.

“The goal became not just to look at the ecological variables, but to look at the whole thing. Once we accounted for as many other factors as we could, we wanted to see if we could still detect an environmental effect,” Botero says. “The overall picture is that these beliefs are ultimately shaped by a combination of historical, ecological, and social factors.”

Botero believes that this study is just the tip of the iceberg in examining human behavior from a cross-disciplinary standpoint. The team plans to further this study by exploring the processes that have influenced the evolution of other human behaviors including taboos, circumcision, and the modification of natural habitats.

“We are at an unprecedented time in history,” Botero says. “Now we’re able to harness both data and a combination of multidisciplinary expertise to explore these kinds of questions in an empirical way.”


Journal Reference:

  1. C. A. Botero, B. Gardner, K. R. Kirby, J. Bulbulia, M. C. Gavin, R. D. Gray. The ecology of religious beliefsProceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1408701111

Cientistas descobrem dois genes relacionados a crimes violentos (Zero Hora)

A característica estava presente em 10% dos 900 criminosos finlandeses analisados em estudo de instituto sueco

Mais um estudo científico conclui que a genética pode estar relacionada a crimes violentos. Desta vez, a partir da análise de quase 900 criminosos na Finlândia, pesquisadores descobriram dois genes que ampliaram em 13 vezes as chances de a pessoa ter comportamento violento repetidamente.

Veja a matéria completa em: http://zh.clicrbs.com.br/rs/noticias/planeta-ciencia/noticia/2014/10/cientistas-descobrem-dois-genes-relacionados-a-crimes-violentos-4630569.html

(Zero Hora)

In Amazon wars, bands of brothers-in-law (University of Utah)

[Chagnon is restless.Gosh]

27-Oct-2014

Contact: Lee J. Siegel

How culture influences violence among the Amazon’s ‘fierce people’

IMAGE: In this mid-1960s photo, men from two Yanomamo villages in the Amazon engage in nonhostile combat to determine the strength and fighting prowess of potential alliance partners. A new study…

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SALT LAKE CITY, Oct. 27, 2014 – When Yanomamö men in the Amazon raided villages and killed decades ago, they formed alliances with men in other villages rather than just with close kin like chimpanzees do. And the spoils of war came from marrying their allies’ sisters and daughters, rather than taking their victims’ land and women.

Those findings – which suggest how violence and cooperation can go hand-in-hand and how culture may modify any innate tendencies toward violence – come from a new study of the so-called “fierce people” led by provocative anthropologist Napoleon Chagnon and written by his protégé, University of Utah anthropologist Shane Macfarlan.

Macfarlan says the researchers had expected to find the Yanomamö fought like “bands of brothers” and other close male kin like fathers, sons and cousins who live in the same community and fight nearby communities. That is how fights are conducted by chimpanzees – the only other apes besides humans that form coalitions to fight and kill.

Instead, “a more apt description might be a ‘band of brothers-in-law,'” in which Yanomamö men ally with similar-age men from nearby villages to attack another village, then marry their allies’ female kin, Macfarlan, Chagnon and colleagues write in the study, published this week in the journal Proceedings of the National Academy of Sciences.

The study provides a mechanism to explain why Yanomamö warriors in a 1988 Chagnon study had more wives and children than those who did not kill.

“We are showing these guys individually get benefits from engaging in killing,” Macfarlan says. “They’re getting long-term alliance partners – other guys they can trust to get things done. And they are getting marriage opportunities.”

Since his 1968 book “Yanomamö: The Fierce People,” Chagnon has been harshly criticized by some cultural anthropologists who claim he places undue emphasis on genes and biology as underpinnings of human violence, based on his 1964-1993 visits to the Yanomamö. Defenders such as Macfarlan say Chagnon takes a much more balanced view, and that “it’s never a genes-versus-culture argument. They operate in tandem.”

Chagnon got what was seen as vindication in 2012 when he was elected to the prestigious National Academy of Sciences. The new study, with Macfarlan as first author and Chagnon as senior author – is Chagnon’s inaugural PNAS article as a member.

Macfarlan joined the University of Utah faculty this year an assistant professor of anthropology. He worked as Chagnon’s postdoctoral fellow at the University of Missouri from January 2013 to June 2014. Chagnon and Macfarlan conducted the study with two Missouri colleagues: anthropologists Robert S. Walker and Mark V. Flinn.

Models of Warfare

The Yanomamö – hunters and farmers who live in southern Venezuela and northern Brazil – once gained social status as “unokai” for killing.

Up to 20 Yanomamö (pronounced yah-NO-mama, but also spelled Yanomami or Yanomama) would sneak up on another village at dawn, “shoot the first person they saw and then hightail back home,” Macfarlan says. Some Yanomamö men did this once, some up to 11 times and some never killed. (Data for the study, collected in the 1980s, covered somewhat earlier times when spears, bows and arrows were the primary weapons.)

IMAGE: University of Utah anthropologist Shane Macfarlan, shown here, is first author of a new study with provocative anthropologist Napoleon Chagnon about the Yanomamo, or so called ‘fierce people’ of…

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Macfarlan says the classic debate has been, “does warfare in small-scale societies like the Yanomamö resemble chimpanzee warfare?” – a theory known as the “fraternal interest group” model, in which bands of brothers, fathers, sons and paternal uncles all living in the same community fight other similar communities.

The new study asked whether Yanomamö killing follows that model or the “strategic alliance model,” which the researchers dub the “band of brothers-in-law” model. This model – supported by the study’s findings – indicates that Yanomamö men form alliances not with close kin from the same community, but with men from other communities. After killing together, a bond is formed and they often marry each other’s daughters or sisters and move into one or the other’s village or form a new village.

“When we started off this project, we all assumed it would be the chimpanzee-like model. But in human groups we have cultural rules that allow us to communicate with other communities. You certainly don’t see chimpanzees doing this.”

Is the study a retreat from what Chagnon’s critics see as too much focus on genetic and biological underpinnings of violence? Macfarlan says no, that Chagnon “has never been as all-biology as people have painted him. Most of his published research shows how unique cultural rules make the Yanomamö an interesting group of people.”

Earlier research suggested that for chimps, warfare is adaptive in an evolutionary sense, and that it also benefits small-scale human societies. The new study asked, “If warfare is adaptive, in what way do the adaptive benefits flow?” Macfarlan says.

“Some people, myself included, said, to the victor goes the spoils, because if you conquer another territory, you might take their land, food or potentially their females.”

But the new study indicates “the adaptive benefits are the alliances you build by perpetrating acts of warfare,” he adds. “It’s not that you are taking land or females from the vanquished group, but for the Yanomamö, what you acquire is that you can exchange resources with allies, such as labor and, most importantly, female marriage partners.”

The study’s findings that the Yanomamö form strategic alliances to kill suggest that “our ultracoooperative tendencies tend to go hand-in-hand with our ultralethal tendencies,” Macfarlan says. “We show a relationship between cooperation and violence at a level unseen in other organisms.” That may seem obvious for allied nations in modern wars, but “we’re saying that even in small-scale societies this is the case.”

IMAGE: Men from one Yanomamo village in the Amazon ‘dance’ in a neighboring village to show off their military prowess, weaponry and group cohesion after they were invited to a…

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How the Study was Conducted

The new study analyzed data collected by Chagnon in the 1980s, when about 25,000 Yanomamö lived in about 250 villages ranging from 25 to 400 people.

The study examined 118 Yanomamö warriors or unokai who had killed a total of 47 people by forming raiding parties of two to 15 men. The researchers analyzed the relationships between every possible pair of men in those raiding parties. Among the 118 unokai men, there were 509 possible pairs. Macfarlan says the findings revealed surprises about the relationship between co-unokai – pairs of men who kill together:

  • Only 22 percent of men who kill together were from the same lineage.
  • Only 34 percent of co-unokai pairs were from the same place of birth. “Guys who come from different places of birth are more likely to kill together.”
  • Among co-killers known to be related, a majority were related on their mother’s side rather than their father’s side – more evidence of forming alliances beyond the immediate paternal kinship group. In Yanomamö culture, true kin are viewed as being on the paternal side, while maternal relatives are seen as belonging to another social group.
  • The Yanomamö preferred forming coalitions with men within a median of age difference of 8 years. “The more similar in age, the more likely they will kill multiple times,” Macfarlan says.
  • Of the 118 unokai, 102 got married in a total of 223 marriages to 206 women. Of married killers, 70 percent married at least one woman from the same paternal line as an ally in killing. And “the more times they kill together, the more likely they are going to get marriage partners from each other’s family line,” Macfarlan says.
  • As a result, “The more times the guys kill together, the more likely they are to move into the same village later in life, despite having come from different village.”

The study found allies-in-killing often are somewhere between maternal first and second cousins, Macfarlan says. Under Yanomamö rules, a man’s ideal marriage partner is a maternal first cousin, who would be the offspring of your mother’s brother. He says Yanomamö rules allow marriage to a maternal first cousin, but not a paternal first cousin.

Despite debate over the biological roots of deadly coalitions in chimps and humans, the new study shows how culture can make it “uniquely human” because if Yanomamö men “kill together, they are plugged into this social scene, this marriage market,” Macfarlan says. “They are playing the game of their culture.”

Firelight talk of the Kalahari Bushmen (University of Utah)

22-Sep-2014

Lee J. Siegel

Did tales told over fires aid our social and cultural evolution?

IMAGE: A !Kung Bushman, sporting a Calvin Klein hat, tells stories at a firelight gathering in Africa’s Kalahari Desert. University of Utah anthropologist Polly Wiessner has published a new study of…

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SALT LAKE CITY, Sept. 22, 2014 – After human ancestors controlled fire 400,000 to 1 million years ago, flames not only let them cook food and fend off predators, but also extended their day.

A University of Utah study of Africa’s Kalahari Bushmen suggests that stories told over firelight helped human culture and thought evolve by reinforcing social traditions, promoting harmony and equality, and sparking the imagination to envision a broad sense of community, both with distant people and the spirit world.

Researchers previously studied how cooking affected diets and anatomy, but “little is known about how important the extended day was for igniting the embers of culture and society,” anthropology professor Polly Wiessner writes in a study published online today in the journal Proceedings of the National Academy of Sciences.

“There is something about fire in the middle of the darkness that bonds, mellows and also excites people. It’s intimate,” says Wiessner, who has studied the Bushmen for 40 years. “Nighttime around a fire is universally time for bonding, for telling social information, for entertaining, for a lot of shared emotions.”

Wiessner’s study, which she calls “exploratory,” analyzed scores of daytime and firelight conversations among !Kung Bushmen – also known as Ju/’hoansi Bushmen – some 4,000 of which now live in the Kalahari Desert of northeast Namibia and northwest Botswana. (The exclamation, slash and apostrophe symbols represent click sounds in their language.) They are among several groups of Kalahari Bushmen.

Why study the campfire tales of Bushmen?

“We can’t tell about the past from the Bushmen,” Wiessner says. “But these people live from hunting and gathering. For 99 percent of our evolution, this is how our ancestors lived. What transpires during the firelit night hours by hunter-gatherers? It helps answer the question of what firelit space contributes to human life.”

She writes: “Stories are told in virtually all hunter-gatherer societies; together with gifts, they were the original social media.”

IMAGE: !Kung Kalahari Bushmen in Africa sit in camp. A University of Utah study of nighttime gatherings around fires by these hunter-gatherers suggests that human cultural development was advanced when human…

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From the Workaday World to Nights of Bonding and Wonder

In her study, “Embers of Society: Firelight Talk among the Ju/’hoansi Bushmen,” Wiessner says archaeological evidence indicates human ancestors had sporadic control of fire 1 million or more years ago, and regularly used it after 400,000 years ago.

“Fire altered our circadian rhythms, the light allowed us to stay awake, and the question is what happened in the fire-lit space? What did it do for human development?” asks Wiessner, who earlier this year was among three University of Utah researchers elected to the National Academy of Sciences.

Wiessner says !Kung Bushmen hold firelight gatherings most nights in groups of up to 15 people. A camp has hearths for each family, but at night people often converge at a single hearth. She analyzed only conversations involving five or more people.

Firelight stories deal with topics such as past hunts, fights over meat, marriage, premarital customs, murder, bush fires, birth, getting lost, interactions with other groups, truck breakdowns, being chased by animals, disputes and extramarital affairs. And there also are traditional myths.

For her study, Wiessner analyzed two sets of data:

  • Notes she took in 1974 (initially for another purpose) of 174 daytime and nighttime conversations at two !Kung camps in northwest Botswana. Each conversation lasted more than 20 to 30 minutes and involved five to 15 people.
  • Digital recordings, transcribed by educated Bushmen, of 68 firelight stories Wiessner originally heard in the 1970s but came back to have retold and recorded during three visits in 2011-2013 to !Kung villages in Botswana and Namibia.

Wiessner found daytime conversations differed much from firelight discussions. Of daytime conversations, 34 percent were complaints, criticism and gossip to regulate social relationships; 31 percent were economic matters, such as hunting for dinner; 16 percent were jokes; only 6 percent were stories and the rest were other topics

But at night, 81 percent of the conversations involved stories, and only 7 percent were complaints, criticism and gossip and 4 percent were economic.

IMAGE: A group of !Kung Bushmen in Africa’s Kalahari Desert work together to transcribe and translate a recorded firelight conversation into a written text. Such translations were used by University of…

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Bonding with People Near and Far – and with the Supernatural

Wiessner found how conversations reinforced major !Kung social institutions and values: arranged marriages, the kinship system, a social structure based on equality, the sharing of food during times of hardship, land rights, trance healing and xaro, a system of exchange that involved pledges of mutual assistance, including housing and food, in troubled times.

“What I found was a big difference between day and night conversation, the kinds of information transmitted and the use of imaginary thought,” Wiessner says.

“Day conversation has a lot to do with economic activities – working, getting food, what resources are where,” she says. “It has a lot to do with social issues and controls: criticism, complaints and gripes.”

“At night, people really let go, mellow out and seek entertainment. If there have been conflicts in the day, they overcome those and bond. Night conversation has more to do with stories, talking about the characteristics of people who are not present and who are in your broader networks, and thoughts about the spirit world and how it influences the human world. You have singing and dancing, too, which bonds groups.”

Healers dance and go into trances, “travel to god’s village and communicate with the spirits of deceased loved ones who are trying to take sick people away,” Wiessner says.

She says nonhuman primates don’t maintain mutually supportive ties outside their group: “We are really unique. We create far-flung ties outside our groups.”

Such extended communities allowed humans “to colonize our planet because they had networks of mutual support, which you see expressed today in our capacity for social networking” she adds. “Humans form communities that are not together in space, but are in our heads – virtual communities. They are communities in our heads. For the Bushmen, they may be up to 120 miles away.”

Wiessner suggests that firelight stories, conversations, ceremonies and celebrations sparked human imagination and “cognitive capacities to form these imagined communities, whether it’s our social networks, all of our relatives on Earth or communities that link us to the spirit world.” She says they also bolstered the human ability to “read” what others are thinking – not just their thoughts or intentions, but their views toward other people.

What Has Electricity Done to Us?

Examining how firelight extended the day prompted Wiessner to wonder about modern society, asking, “What happens when economically unproductive firelit time is turned to productive time by artificial lighting?”

Parents read stories or show videos to their children, but now, “work spills into the night. We now sit on laptops in our homes. When you are able to work at night, you suddenly have a conflict: ‘I have only 15 minutes to tell my kids a bedtime story. I don’t have time to sit around and talk.’ Artificial light turned potential social time into potential work time. What happens to social relations?”

Her research raises that question, but doesn’t answer it.

Alternate mechanism of species formation picks up support, thanks to a South American ant (University of Rochester )

21-Aug-2014

 

By Peter Iglinski

A queen ant of the host species Mycocepurus goeldii.

A newly-discovered species of ant supports a controversial theory of species formation. The ant, only found in a single patch of eucalyptus trees on the São Paulo State University campus in Brazil, branched off from its original species while living in the same colony, something thought rare in current models of evolutionary development.

“Most new species come about in geographic isolation,” said Christian Rabeling, assistant professor of biology at the University of Rochester. “We now have evidence that speciation can take place within a single colony.”

The findings by Rabeling and the research team were published today in the journal Current Biology.

In discovering the parasitic Mycocepurus castrator, Rabeling and his colleagues uncovered an example of a still-controversial theory known as sympatric speciation, which occurs when a new species develops while sharing the same geographic area with its parent species, yet reproducing on its own.“While sympatric speciation is more difficult to prove,” said Rabeling, “we believe we are in the process of actually documenting a particular kind of evolution-in-progress.”

New species are formed when its members are no longer able to reproduce with members of the parent species. The commonly-accepted mechanism is called allopatric speciation, in which geographic barriers—such as mountains—separate members of a group, causing them to evolve independently.

“Since Darwin’s Origin of Species, evolutionary biologists have long debated whether two species can evolve from a common ancestor without being geographically isolated from each other,” said Ted Schultz, curator of ants at the Smithsonian’s National Museum of Natural History and co-author of the study. “With this study, we offer a compelling case for sympatric evolution that will open new conversations in the debate about speciation in these ants, social insects and evolutionary biology more generally.”

A queen ant of the parasitic species Mycocepurus castrator.

M. castrator is not simply another ant in the colony; it’s a parasite that lives with—and off of—its host, Mycocepurus goeldii. The host is a fungus-growing ant that cultivates fungus for its nutritional value, both for itself and, indirectly, for its parasite, which does not participate in the work of growing the fungus garden. That led the researchers to study the genetic relationships of all fungus-growing ants in South America, including all five known and six newly discovered species of the genus Mycocepurus, to determine whether the parasite did evolve from its presumed host. They found that the parasitic ants were, indeed, genetically very close to M. goeldii, but not to the other ant species.

They also determined that the parasitic ants were no longer reproductively compatible with the host ants—making them a unique species—and had stopped reproducing with their host a mere 37,000 years ago—a very short period on the evolutionary scale.

A big clue for the research team was found by comparing the ants’ genes, both in the cell’s nucleus as well as in the mitochondria—the energy-producing structures in the cells. Genes are made of units called nucleotides, and Rabeling found that the sequencing of those nucleotides in the mitochondria is beginning to look different from what is found in the host ants, but that the genes in the nucleus still have traces of the relationship between host and parasite, leading him to conclude that M. castrator has begun to evolve away from its host.

Rabeling explained that just comparing some nuclear and mitochondrial genes may not be enough to demonstrate that the parasitic ants are a completely new species. “We are now sequencing the entire mitochondrial and nuclear genomes of these parasitic ants and their host in an effort to confirm speciation and the underlying genetic mechanism.”

The parasitic ants need to exercise discretion because taking advantage of the host species is considered taboo in ant society. Offending ants have been known to be killed by worker mobs. As a result, the parasitic queen of the new species has evolved into a smaller size, making them difficult to distinguish from a host worker.

Host queens and males reproduce in an aerial ceremony, in the wet tropics only during a particular season when it begins to rain. Rabeling found that the parasitic queens and males, needing to be more discreet about their reproductive activities, diverge from the host’s mating pattern. By needing to hide their parasitic identity, M. castrator males and females lost their special adaptations that allowed them to reproduce in flight, and mate inside the host nest, making it impossible for them to sexually interact with their host species.

The research team included Ted Schultz of the Smithsonian Institution’s National Museum of Natural History, Naomi Pierce of Harvard University, and Maurício Bacci, Jr of the Center for the Study of Social Insects (São State University, Rio Claro, Brazil).

Our Microbiome May Be Looking Out for Itself (New York Times)

A highly magnified view of Enterococcus faecalis, a bacterium that lives in the human gut. Microbes may affect our cravings, new research suggests.CreditCenters for Disease Control and Prevention

Your body is home to about 100 trillion bacteria and other microbes, collectively known as your microbiome. Naturalists first became aware of our invisible lodgers in the 1600s, but it wasn’t until the past few years that we’ve become really familiar with them.

This recent research has given the microbiome a cuddly kind of fame. We’ve come to appreciate how beneficial our microbes are — breaking down our food, fighting off infections and nurturing our immune system. It’s a lovely, invisible garden we should be tending for our own well-being.

But in the journal Bioessays, a team of scientists has raised a creepier possibility. Perhaps our menagerie of germs is also influencing our behavior in order to advance its own evolutionary success — giving us cravings for certain foods, for example.

Maybe the microbiome is our puppet master.

“One of the ways we started thinking about this was in a crime-novel perspective,” said Carlo C. Maley, an evolutionary biologist at the University of California, San Francisco, and a co-author of the new paper. “What are the means, motives and opportunity for the microbes to manipulate us? They have all three.”

The idea that a simple organism could control a complex animal may sound like science fiction. In fact, there are many well-documented examples of parasites controlling their hosts.

Some species of fungi, for example, infiltrate the brains of ants and coax them to climb plants and clamp onto the underside of leaves. The fungi then sprout out of the ants and send spores showering onto uninfected ants below.

How parasites control their hosts remains mysterious. But it looks as if they release molecules that directly or indirectly can influence their brains.

Our microbiome has the biochemical potential to do the same thing. In our guts, bacteria make some of the same chemicals that our neurons use to communicate with one another, such as dopamine and serotonin. And the microbes can deliver these neurological molecules to the dense web of nerve endings that line the gastrointestinal tract.

A number of recent studies have shown that gut bacteria can use these signals to alter the biochemistry of the brain. Compared with ordinary mice, those raised free of germs behave differently in a number of ways. They are more anxious, for example, and have impaired memory.

Adding certain species of bacteria to a normal mouse’s microbiome can reveal other ways in which they can influence behavior. Some bacteria lower stress levels in the mouse. When scientists sever the nerve relaying signals from the gut to the brain, this stress-reducing effect disappears.

Some experiments suggest that bacteria also can influence the way their hosts eat. Germ-free mice develop more receptors for sweet flavors in their intestines, for example. They also prefer to drink sweeter drinks than normal mice do.

Scientists have also found that bacteria can alter levels of hormones that govern appetite in mice.

Dr. Maley and his colleagues argue that our eating habits create a strong motive for microbes to manipulate us. “From the microbe’s perspective, what we eat is a matter of life and death,” Dr. Maley said.

Different species of microbes thrive on different kinds of food. If they can prompt us to eat more of the food they depend on, they can multiply.

Microbial manipulations might fill in some of the puzzling holes in our understandings about food cravings, Dr. Maley said. Scientists have tried to explain food cravings as the body’s way to build up a supply of nutrients after deprivation, or as addictions, much like those for drugs like tobacco and cocaine.

But both explanations fall short. Take chocolate: Many people crave it fiercely, but it isn’t an essential nutrient. And chocolate doesn’t drive people to increase their dose to get the same high. “You don’t need more chocolate at every sitting to enjoy it,” Dr. Maley said.

Perhaps, he suggests, the certain kinds of bacteria that thrive on chocolate are coaxing us to feed them.

John F. Cryan, a neuroscientist at University College Cork in Ireland who was not involved in the new study, suggested that microbes might also manipulate us in ways that benefited both them and us. “It’s probably not a simple parasitic scenario,” he said.

Research by Dr. Cryan and others suggests that a healthy microbiome helps mammals develop socially. Germ-free mice, for example, tend to avoid contact with other mice.

That social bonding is good for the mammals. But it may also be good for the bacteria.

“When mammals are in social groups, they’re more likely to pass on microbes from one to the other,” Dr. Cryan said.

“I think it’s a very interesting and compelling idea,” said Rob Knight, a microbiologist at the University of Colorado, who was also not involved in the new study.

If microbes do in fact manipulate us, Dr. Knight said, we might be able to manipulate them for our own benefit — for example, by eating yogurt laced with bacteria that would make us crave healthy foods.

“It would obviously be of tremendous practical importance,” Dr. Knight said. But he warned that research on the microbiome’s effects on behavior was “still in its early stages.”

The most important thing to do now, Dr. Knight and other scientists said, was to run experiments to see if microbes really are manipulating us.

Mark Lyte, a microbiologist at the Texas Tech University Health Sciences Center who pioneered this line of research in the 1990s, is now conducting some of those experiments. He’s investigating whether particular species of bacteria can change the preferences mice have for certain foods.

“This is not a for-sure thing,” Dr. Lyte said. “It needs scientific, hard-core demonstration.”

Wild sheep show benefits of putting up with parasites (Science Daily)

Date: August 7, 2014

Source: Princeton University

Summary: In the first evidence that natural selection favors an individual’s infection tolerance, researchers have found that an animal’s ability to endure an internal parasite strongly influences its reproductive success. The finding could provide the groundwork for boosting the resilience of humans and livestock to infection.

The researchers examined the relationship between each sheep’s body weight and its level of infection by nematodes, tiny parasitic worms that thrive in the gastrointestinal tract of sheep. This scanning electron micrograph shows nematodes on the surface of a sheep’s gut with a field of view of approximately one centimeter. An economic detriment to sheep farmers, nematodes infect both wild and domesticated sheep, resulting in weight loss, reduced wool growth and death. Credit: Photo by David Smith/Moredun Research Institute

In the first evidence that natural selection favors an individual’s infection tolerance, researchers from Princeton University and the University of Edinburgh have found that an animal’s ability to endure an internal parasite strongly influences its reproductive success. Reported in the journalPLoS Biology, the finding could provide the groundwork for boosting the resilience of humans and livestock to infection.

The researchers used 25 years of data on a population of wild sheep living on an island in northwest Scotland to assess the evolutionary importance of infection tolerance. They first examined the relationship between each sheep’s body weight and its level of infection with nematodes, tiny parasitic worms that thrive in the gastrointestinal tract of sheep. The level of infection was determined by the number of nematode eggs per gram of the animal’s feces.

While all of the animals lost weight as a result of nematode infection, the degree of weight loss varied widely: an adult female sheep with the maximum egg count of 2,000 eggs per gram of feces might lose as little as 2 percent or as much as 20 percent of her body weight. The researchers then tracked the number of offspring produced by each of nearly 2,500 sheep and found that sheep with the highest tolerance to nematode infection produced the most offspring, while sheep with lower parasite tolerance left fewer descendants.

To measure individual differences in parasite tolerance, the researchers used statistical methods that could be extended to studies of disease epidemiology in humans, said senior author Andrea Graham, an assistant professor of ecology and evolutionary biology at Princeton. Medical researchers have long understood that people with similar levels of parasite infection can experience very different symptoms. But biologists are just beginning to appreciate the evolutionary importance of this individual variation.

“For a long time, people assumed that if you knew an individual’s parasite burden, you could perfectly predict its health and survival prospects,” Graham said. “More recently, evolutionary biologists have come to realize that’s not the case, and so have developed statistical tools to measure variation among hosts in the fitness consequences of infection.”

Graham and her colleagues used the wealth of information collected over many years on the Soay sheep living on the island of Hirta, about 100 miles west of the Scottish mainland. These sheep provide a unique opportunity to study the effects of parasites, weather, vegetation changes and other factors on a population of wild animals. Brought to the island by people about 4,000 years ago, the sheep have run wild since the last permanent human inhabitants left Hirta in 1930. By keeping a detailed pedigree, the researchers of the St Kilda Soay Sheep Project can trace any individual’s ancestry back to the beginning of the project in 1985, and, conversely, can count the number of descendants left by each individual.

Expending energy to fight infection

Nematodes puncture an animal’s gut and can impede the absorption of nutrients. Therefore, tolerance to nematode infection could result from an ability to make up for the lost nutrition, or from the ability to repair damage the parasites cause to the gut, Graham said. “This island is way out in the North Atlantic, where the sun doesn’t shine much,” she said. “So tolerant individuals might be the ones who are better able to compete for food or better able to assimilate protein and other useful nutrients from the limited forage.”

Tolerant animals might invest energy in gut repair, but would then be expected to incur costs. Graham and her colleagues identified a similar evolutionary tradeoff in a 2010 study that compared immune-response levels and reproductive success in female Soay sheep. They found that animals with strong antibody responses produced fewer offspring each year, but also lived longer. The team has not yet been able to detect costs of parasite tolerance in the sheep, but such costs could help explain variation in tolerance if the most tolerant animals were at a disadvantage under particular conditions.

While the PLoS Biology findings provide strong evidence that natural selection favors infection tolerance, they do raise questions, such as how the tolerance is generated, and why variation might persist from one generation to the next despite the reproductive advantage of tolerance, Graham said. The data in this study did not permit the researchers to detect a genetic component to tolerance. If genetics do play a role, she suspects multiple genes may interact with environmental factors to determine tolerance; ongoing research will help to tease apart these possibilities.

Understanding the genetic underpinnings of nematode tolerance could someday guide efforts to boost tolerance in livestock by identifying and selectively breeding those animals that exhibit a heightened parasite tolerance, said David Schneider, an associate professor of microbiology and immunology at Stanford University.

“This study shows that parasite tolerance can have a profound effect on animal health and breeding success,” said Schneider, who is familiar with the work but was not involved in it. “In the long term, this suggests that it could be profitable to invest in breeding tolerant livestock.”

In humans and domesticated animals, intestinal parasites are becoming increasingly resistant to the drugs used to treat infections, Graham said. If the availability of nutrients, even just during the first few months of life, impacts lifelong parasite tolerance, simple nutritional supplements could be an effective way to promote tolerance in people. About 2 billion people are persistently infected with intestinal nematode parasites worldwide, mostly in developing nations. Children are especially vulnerable to the worms’ effects, which include anemia, stunted growth and cognitive difficulties.

“Ideally, we would clear the worms from the bellies of the kids who have those heavy burdens,” Graham said. “But if we could also understand how to ameliorate the health consequences and thus promote tolerance of nematodes, that could be a very powerful tool.”

Journal Reference:

  1. Adam D. Hayward, Daniel H. Nussey, Alastair J. Wilson, Camillo Berenos, Jill G. Pilkington, Kathryn A. Watt, Josephine M. Pemberton, Andrea L. Graham. Natural Selection on Individual Variation in Tolerance of Gastrointestinal Nematode Infection. PLoS Biology, 2014; 12 (7): e1001917 DOI:10.1371/journal.pbio.1001917

Darwinismo 2.0 (Valor Econômico)

JC e-mail 4976, de 24 de junho de 2014

Artigo de José Eli da Veiga publicado no Valor Econômico

Até o início dos anos 1980 o darwinismo foi amesquinhado pela concepção de que a sobrevivência dos mais aptos só decorreria da feroz competição que caracterizaria a “luta” pela existência. Por oitenta anos foi rejeitada a desviante interpretação das obras de Darwin proposta em “Ajuda Mútua: um Fator de Evolução”, livro com argutas observações sobre a extraordinária cooperação que caracteriza as vidas de abelhas, formigas e vários outros animais, publicado em 1902, no exílio londrino, pelo sessentão príncipe russo Piotr Kropotkin.

Mesmo que não tenha havido reconhecimento explícito, a perspicácia desse expoente do anarquismo começou a ser redimida quando um dos então mais promissores ramos da matemática – a Teoria dos Jogos – foi mobilizado para solucionar uma das questões que mais intrigava os pesquisadores, especialmente os das humanidades: num mundo de egoístas, desprovido de governo central, em que condições pode emergir a cooperação?

Resposta original e persuasiva foi dada em 1981 pelo cientista político da Universidade de Michigan, Robert Axelrod, que três anos depois lançou o hoje clássico “A Evolução da Cooperação” (Ed. Leopardo, 2010). Um livro que deveria tomar o lugar daquelas bíblias gratuitas achadas nos criados-mudos dos hotéis, diz Richard Dawkins, o célebre autor de “O Gene Egoísta” em prefácio à edição de 2006.

A proeza de Axelrod foi executar inéditas simulações computacionais que confirmaram hipóteses formuladas na década anterior por biólogos evolutivos: nepotismo e reciprocidade seriam os dois fatores determinantes da cooperação. Na ausência do primeiro, ela estaria na dependência de um padrão comportamental em que cada um dos atores repete o movimento do outro, reagindo positivamente a atitudes cooperativas e negativamente a gestos hostis.

Ainda em plena Guerra Fria, quando o risco de um “inverno nuclear” exigia a cooperação bipolar entre EUA e URSS, o que poderia fazer mais sucesso do que essa orientação apelidada de “tit-for-tat”, título de uma das populares comédias da dupla “O Gordo e o Magro”? Embora seja traduzida por “olho-por-olho, dente-por-dente”, essa expressão está mais próxima do “toma-lá-dá-cá”, pois é uma estratégia que exige prévio arranque cooperativo.

Como sempre ocorre na ciência, boa resposta a uma grande questão faz com que pipoquem novas dúvidas. Por exemplo: se por mera razão acidental um dos atores falhar em fazer o esperado movimento positivo, isso por si só inviabiliza a continuidade da cooperação? E o que ocorreria quando o esquema de cooperação envolvesse mais do que dois atores? Foram questões como essas que alavancaram o fulgurante avanço da biologia matemática nos últimos vinte anos. O padrão “toma-lá-dá-cá” hoje não passa de uma das três modalidades de uma das cinco dinâmicas de cooperação evidenciadas.

O “tit-for-tat” é manifestação rudimentar do que passou a ser chamado de “reciprocidade direta”. Novas simulações indicaram que eventual passo em falso pode engendrar uma segunda chance, em estratégia apelidada de “toma-lá-dá-cá generoso”, a origem evolutiva do perdão. E desdobramentos ainda mais sofisticados revelaram a existência de uma terceira forma de reciprocidade direta, na qual o agente inverte sua atitude anterior quando nota que as coisas vão mal, mas logo depois volta a cooperar. Algo que já era bem conhecido na etologia como comportamento “Win-Stay, Lose-Shift”, comum entre pombos, macacos, ratos e camundongos.

O segundo vetor da cooperação, chamado de “reciprocidade indireta”, foi crucial para a evolução da linguagem e para o próprio desenvolvimento do cérebro humano, pois se baseia no fenômeno da reputação. Neste caso, o que condiciona as atitudes dos atores são comportamentos anteriores em relações com terceiros. A cooperação avança quando a probabilidade de um agente se inteirar sobre a reputação do outro compensa o custo/benefício do ato altruísta.

Os demais determinantes da cooperação são as três formas em que ocorre a seleção natural, pois, além da já mencionada nepotista (de parentesco), ela não opera apenas entre indivíduos, mas também entre grupos (multinível) e nas redes (espacial).

Mesmo que as observações acima não sejam suficientes para que se possa ter uma boa ideia das descobertas da biologia matemática no âmbito da dinâmica evolutiva, elas certamente permitem notar que o darwinismo aponta tanto para “luta” quanto para “acomodação” pela existência. Exposição rigorosa e extremamente amigável desse darwinismo 2.0 está em “SuperCooperators – Altruism, Evolution, and Why We Need Each Other to Succeed” (Free Press, 2011), do austríaco Martin A. Nowak, biólogo matemático que está em Harvard depois de ter brilhado em Oxford e Princeton, e que contou com a inestimável ajuda do jornalista científico britânico Roger Highfield.

Esse sim é um livro que mereceria ser distribuído gratuitamente. Não para substituir bíblias cristãs, mas para promover o entendimento das origens naturais dos códigos de ética de todas as grandes religiões.

José Eli da Veiga é professor sênior do Instituto de Energia e Ambiente da USP e autor de “A desgovernança mundial da sustentabilidade” (Editora 34, 2013). Escreve mensalmente às terças-feiras. http://www.zeeli.pro.br

(Valor Econômico)
http://www.valor.com.br/opiniao/3591840/darwinismo-20#ixzz35ZWruc22

Beyond the bones: The archaeology of human networks (New Scientist)

21 July 2014 by Alun Anderson

Magazine issue 2978

Book information
Thinking Big: How the evolution of social life shaped the human mindby Clive Gamble, John Gowlett and Robin Dunbar
Published by: Thames & Hudson
Price: £18.95
Human Evolution: A Pelican introduction by Robin Dunbar
Published by: Pelican Books
Price: £5.99

Did a focus on local life leave Neanderthals perilously isolated? (Image: Elisabeth Daynes/SPL)

The idea of human as networker is fast replacing the idea of human as toolmaker in the story of the human brain, claim two new books on our evolution

“HELL is other people,” goes Jean-Paul Sartre’s famous line. It is a hell that may have created us and our culture, judging by two new books. They show that the idea that we are defined by our struggles to deal with our fellow humans is shaking up archaeology and how we think about the key force driving human evolution.

The first book is Thinking Big by archaeologists Clive Gamble and John Gowlett and evolutionary psychologist Robin Dunbar. It is the story of a seven-year project – From Lucy to Language – that confronted archaeologists with the social brain hypothesis of human evolution.

The result is a dramatic demolition of the “stones and bones” approach to archaeology, which keeps researchers firmly fixed only on the physical evidence they dig up, and a move towards a grand look at the evolving human mind. There is “more to humanity than the bits of chipped bone”, write the authors as they seek a framework for all human psychological traits, from kinship and laughter to language and ceremony. Old dogma is derided as never moving beyond “WYSWTW” (What You See is What There Was).

The second book is a solo effort by Dunbar, the key thinker behind the social brain hypothesis. In Human Evolution, he lays out the big ideas that the archaeologists later took up. At its heart is the observation that as brains grew bigger, so did the groups we live in: bigger brains were built for and by social life. Modern humans have a cognitive limit of about 150 friends and family (the well-known “Dunbar’s number”). Within that circle are an average of five “intimates”, 15 best friends and 50 good friends. Chimps have an average community size of 55.

Studies of living, non-human primates show why you might need bigger brains to live in bigger groups. The more others are around, the more likely you are to be bullied out of a juicy food patch or a safe sleeping site. Such stress can be hell, especially for low-ranking females, who can be driven into infertility. To cope, primates create cliques of allies which they sustain through the pleasurable endorphin rush induced by regular mutual grooming. This solution fails if groups grow bigger, for there is not enough time for one-on-one attention. Bigger brains are key to developing smarter ways of dealing with others, the theory goes.

For Dunbar, these included laughter and singing, both great endorphin-releasers within groups. There was also fire, which gave light so evenings could be used for cooking and more “social grooming”. Then came language, together with a growing ability to read others’ intentions, which ultimately made it possible to tell stories, maintain far-flung relationships and usereligion to bind communities.

The Thinking Big archaeologists take from Dunbar the grand hypothesis that social life drives human change, switching from a view of “man the toolmaker” to “man the networker”. Alongside that, the proven relationship between brain sizeMovie Camera, group size and mental skills makes it possible to estimate the size of groups our ancestors lived in and their capacity to interact with others.

A fresh look at the Neanderthals is telling. They dominated Europe for 250,000 years, much longer than modern humans. They were skilled hunters, toolmakers and had mastered fire. Their brain size suggests they lived in groups of about 110 and had the cognitive skills to understand the feelings of others. That fits well with archaeological evidence that older and disabled Neanderthals were cared for: they perhaps knew compassion.

So why did they vanish so fast during a time of changing climate, when modern humans prospered? It may be that their mental skills were not quite adequate to maintain relationships beyond immediate group members, something we can do easily. That may have been crucial to our success: in hard times, bigger networks can mean gaining help from distant friends who are still doing well, and who you’ll help in turn. Without that “social storage” of resources, local extinction may loom. Archaeological evidence again tallies with the social brain theory: one study shows that 70 per cent of the raw materials of Neanderthal tools travelled less than 25 kilometres, while 60 per cent of those of contemporaneous humans had travelled more than 25 kilometres.

The two books fit well together but are very different. Thinking Big inspires, but much wonderful research is passed over too briefly amid general argument. An exception is a story from Beeches Pit, a 400,000-year-old site in the east of England. Archaeologists there painstakingly reassembled the flint flakes struck from a rock in the process of making a hand axe. Two flakes were found burnt bright red; they had fallen into a fire just in front of the axe-maker. We can almost see our ancestors working around what must have been a communal fire, for no one person could have gathered enough wood to keep it burning.

Dunbar’s solo work, Human Evolution, however, is a must-read. It has the great strength of showing you the inner workings of an imaginative mind, while allowing you the freedom to think, and even to disagree about whether that hellish social pressure really has given us our distinct cognitive design, along with science and the arts.

This article appeared in print under the headline “Beyond bones and stones”

Alun Anderson is a consultant for New Scientist

Key to adaptation limits of ocean dwellers: Simpler organisms better suited for climate change (Science Daily)

Date: July 1, 2014

Source: Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research

Summary: The simpler a marine organism is structured, the better it is suited for survival during climate change, researchers have discovered this in a new meta-study. For the first time biologists studied the relationship between the complexity of life forms and the ultimate limits of their adaptation to a warmer climate.

The temperature windows of some ocean dwellers as a comparison: the figures for green algae, seaweed and thermophilic bacteria were determined in the laboratory. The fish data stem from investigations in the ocean. Credit: Sina Löschke, Alfred Wegener Institute

The simpler a marine organism is structured, the better it is suited for survival during climate change. Scientists of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, discovered this in a new meta-study, which appears today in the research journal Global Change Biology. For the first time biologists studied the relationship between the complexity of life forms and the ultimate limits of their adaptation to a warmer climate. While unicellular bacteria and archaea are able to live even in hot, oxygen-deficient water, marine creatures with a more complex structure, such as animals and plants, reach their growth limits at a water temperature of 41 degrees Celsius. This temperature threshold seems to be insurmountable for their highly developed metabolic systems.

The current IPCC Assessment Report shows that marine life forms respond very differently to the increasing water temperature and the decreasing oxygen content of the ocean. “We now asked ourselves why this is so. Why do bacteria, for example, still grow at temperatures of up to 90 degrees Celsius, while animals and plants reach their limits at the latest at a temperature of 41 degrees Celsius,” says Dr. Daniela Storch, biologist in the Ecophysiology Department at the Alfred Wegener Institute (AWI) and first author of the current study.

Since years Storch and her colleagues have been investigating the processes that result in animals having a certain temperature threshold up to which they can develop and reproduce. The scientists found that the reason for this is their cardiovascular system. They were able to show in laboratory experiments that this transport system is the first to fail in warmer water. Blood circulation supplies all cells and organs of a living organism with oxygen, but can only do so up to a certain maximum temperature. Beyond this threshold, the transport capacity of this system is no longer sufficient; the animal can then only sustain performance for a short time. Based on this, the biologists had suspected at an early date that there is a relationship between the complex structure of an organism and its limited ability to continue to function in increasingly warm water.

“In our study, therefore, we examined the hypothesis that the complexity could be the key that determines the ultimate adaptability of diverse life forms, from marine archaea to animals, to different living conditions in the course of evolutionary history. That means: the simpler the structure of an organism, the more resistant it should be,” explains the biologist. If this assumption is true, life forms consisting of a single simply structured cell would be much more resistant to high temperatures than life forms whose cell is very complex, such as algae, or whose bodies consist of millions of cells. Hence, the tolerance and adaptability thresholds of an organism type would always be found at its highest level of complexity. Among the smallest organisms, unicellular algae are the least resistant because they have highly complex cell organelles such as chloroplasts for photosynthesis. Unicellular protozoans also have cell organelles, but they are simpler in their structure. Bacteria and archaea entirely lack these organelles.

To test this assumption, the scientists evaluated over 1000 studies on the adaptability of marine life forms. Starting with simple archaea lacking a nucleus, bacteria and unicellular algae right through to animals and plants, they found the species in each case with the highest temperature tolerance within their group and determined their complexity. In the end, it became apparent that the assumed functional principle seems to apply: the simpler the structure, the more heat-tolerant the organism type.

But: “The adaptation limit of an organism is not only dependent on its upper temperature threshold, but also on its ability to cope with small amounts of oxygen. While many of the bacteria and archaea can survive at low oxygen concentrations or even without oxygen, most animals and plants require a higher minimum concentration,” explains Dr. Daniela Storch. The majority of the studies examined show that if the oxygen concentration in the water drops below a certain value, the oxygen supply for cells and tissues collapses after a short time.

The new research results also provide evidence that the body size of an organism plays a decisive role concerning adaptation limits. Smaller animal species or smaller individuals of an animal species can survive at lower oxygen concentration levels and higher temperatures than the larger animals.

“We observe among fish in the North Sea that larger individuals of a species are affected first at extreme temperatures. In connection with climate warming, there is generally a trend that smaller species replace larger species in a region. Today, however, plants and animals in the warmest marine environments already live at their tolerance limit and will probably not be able to adapt. If warming continues, they will migrate to cooler areas and there are no other tolerant animal and plant species that could repopulate the deserted habitats,” says Prof. Dr. Hans-Otto Pörtner of the Alfred Wegener Institute. The biologist initiated the current study and is the coordinating lead author of the chapter “Ocean systems” in the Fifth Assessment Report.

The new meta-study shows that their complex structure sets tighter limits for multicellular organisms, i.e. animals and plants, within which they can adapt to new living conditions. Individual animal species can reduce their body size, reduce their metabolism or generate more haemoglobin in order to survive in warmer, oxygen-deficient water. However, marine animals and plants are fundamentally not able to survive in conditions exceeding the temperature threshold of 41 degrees Celsius.

In contrast, simple unicellular organisms like bacteria benefit from warmer sea water. They reproduce and spread. “Communities of species in the ocean change as a result of this shift in living conditions. In the future animals and plants will have problems to survive in the warmest marine regions and archaea, bacteria as well as protozoa will spread in these areas. There are already studies showing that unicellular algae will be replaced by other unicellular organisms in the warmest regions of the ocean,” says Prof. Dr. Hans-Otto Pörtner. The next step for the authors is addressing the question regarding the role the complexity of species plays for tolerance and adaptation to the third climatic factor in the ocean, i.e. acidification, which is caused by rising carbon dioxide emissions and deposition of this greenhouse gas in seawater.

Living at the limit

For generations ocean dwellers have adapted to the conditions in their home waters: to the prevailing temperature, the oxygen concentration and the degree of water acidity. They grow best and live longest under these living conditions. However, not all creatures that live together in an ecosystem have the same preferences. The Antarctic eelpout, for instance, lives at its lower temperature limit and has to remain in warmer water layers of the Southern Ocean. If it enters cold water, the temperature quickly becomes too cold for it. The Atlantic cod in the North Sea, by contrast, would enjoy colder water as large specimens do not feel comfortable in temperatures over ten degrees Celsius. At such threshold values scientists refer to a temperature window: every poikilothermic ocean dweller has an upper and lower temperature limit at which it can live and grow. These “windows” vary in scope. Species in temperate zones like the North Sea generally have a broader temperature window. This is due to the extensively pronounced seasons in these regions. That means the animals have to withstand both warm summers and cold winters.

The temperature window of living creatures in the tropics or polar regions, in comparison, is two to four times smaller than that of North Sea dwellers. On the other hand, they have adjusted to extreme living conditions. Antarctic icefish species, for example, can live in water as cold as minus 1.8 degrees Celsius. Their blood contains antifreeze proteins. In addition, they can do without haemoglobin because their metabolism is low and a surplus of oxygen is available. For this reason their blood is thinner and the fish need less energy to pump it through the body — a perfect survival strategy. But: icefish live at the limit. If the temperature rises by a few degrees Celsius, the animals quickly reach their limits.

Journal Reference:

  1. Daniela Storch, Lena Menzel, Stephan Frickenhaus, Hans-O. Pörtner. Climate sensitivity across marine domains of life: limits to evolutionary adaptation shape species interactionsGlobal Change Biology, 2014; DOI:10.1111/gcb.12645

*   *   *

Starting With the Oceans, Single-Celled Organisms Will Re-Inherit the Earth (Motherboard)

Written by BEN RICHMOND

July 1, 2014 // 07:41 PM CET

I’ll be the first to cop to being guilty of multi-celled chauvinism: Having complex cells with organelles, which form complex systems allowing you to breathe, achieve consciousness, play volleyball, etc, is pretty much as good as it gets. While we enjoy all these advantages now, though, single-celled, simple organisms are just biding their time. More readily adaptable than us multi-celled organisms, it’s really a simple, single-celled world, and we’re just passing through.

Case in point: the oceans. A team of German researchers just published a paper in the journal Global Change Biology that found that the more simple an organism is, the better off it’s going to be as the oceans warm. Trout will die out, whales will fail, but unicellular bacteria and archaea (a type of microorganism) are going to flourish.

Animals can only develop and reproduce up to a temperature threshold in the water of about 41 degrees Celsius, or 105 degrees Fahrenheit. Beyond this, the cardiovascular system can’t deliver necessary oxygen throughout the body. Even as individual animal species can develop smaller bodies or generate more hemoglobin to survive in warmer and oxygen deficient water, the highly developed metabolic systems that allow for things like eyeballs can’t get over the temperature threshold and the other hurdles it brings, like decreasing oxygen.

Image: Sina Löschke, Alfred Wegener Institute

“The adaptation limit of an organism is not only dependent on its upper temperature threshold, but also on its ability to cope with small amounts of oxygen,”said Daniela Storch, the study’s lead author . “While many of the bacteria and archaea can survive at low oxygen concentrations or even without oxygen, most animals and plants require a higher minimum concentration.”

That’s part of the reason that unicellular organisms are found in the most dramatic settings that Earth has to offer: from Antarctic lakes that were buried under glaciers for 100,000 years, to super-hot hydrothermal vents on the ocean floor, acidic pools in Yellowstone, and the Atacama desert in Chile. When we look around the solar system, we see environments that can’t support complex, multicellular life, but still hold out hope that unicellular life has found a way in Europa’s unseen seas, or below the surface of Mars.

But as the Earth’s climate changes, and the ocean gets warmer and more acidic, complexity goes from an asset to a liability, and simplicity reigns.

“Communities of species in the ocean change as a result of this shift in living conditions. In the future animals and plants will have problems to survive in the warmest marine regions and archaea, bacteria as well as protozoa will spread in these areas,” said Dr. Hans-Otto Pörtner, one of the study’s co-authors. “There are already studies showing that unicellular algae will be replaced by other unicellular organisms in the warmest regions of the ocean.”

The story of life on Earth is, if nothing else, symmetrical. Three and a half billion years ago, prokaryotic cells showed up, without a nucleus or other organelles. Complex, multicellular life emerged with an increase in biomass and decrease in global surface temperature half a billion years ago. In another billion and a half years that complex multicellular life died back out, leaving the planet to the so-called simpler forms of life, as they basked in the light of a much brighter Sun. The best-case scenario is that life lasts until the Sun runs out of fuel, swells into a red giant,and vaporizes whatever is left of our planet in 7.6 billion years.

Multicellular life will have just been a two billion year flicker against a backdrop of adaptable single-celled life. But hey, we had a good run.

Insect diet helped early humans build bigger brains: Quest for elusive bugs spurred primate tool use, problem-solving skills (Science Daily)

Date: July 1, 2014

Source: Washington University in St. Louis

Summary: Figuring out how to survive on a lean-season diet of hard-to-reach ants, slugs and other bugs may have spurred the development of bigger brains and higher-level cognitive functions in the ancestors of humans and other primates, suggests new research.

An adult female tufted capuchin monkey of the Sapajus lineage using a stone tool and a sandstone anvil to crack a palm nut as her infant hangs on. Credit: E. Visalberghi

Figuring out how to survive on a lean-season diet of hard-to-reach ants, slugs and other bugs may have spurred the development of bigger brains and higher-level cognitive functions in the ancestors of humans and other primates, suggests research from Washington University in St. Louis.

“Challenges associated with finding food have long been recognized as important in shaping evolution of the brain and cognition in primates, including humans,” said Amanda D. Melin, PhD, assistant professor of anthropology in Arts & Sciences and lead author of the study.

“Our work suggests that digging for insects when food was scarce may have contributed to hominid cognitive evolution and set the stage for advanced tool use.”

Based on a five-year study of capuchin monkeys in Costa Rica, the research provides support for an evolutionary theory that links the development of sensorimotor (SMI) skills, such as increased manual dexterity, tool use, and innovative problem solving, to the creative challenges of foraging for insects and other foods that are buried, embedded or otherwise hard to procure.

Published in the June 2014 Journal of Human Evolution, the study is the first to provide detailed evidence from the field on how seasonal changes in food supplies influence the foraging patterns of wild capuchin monkeys.

The study is co-authored by biologist Hilary C. Young and anthropologists Krisztina N. Mosdossy and Linda M. Fedigan, all from the University of Calgary, Canada.

It notes that many human populations also eat embedded insects on a seasonal basis and suggests that this practice played a key role in human evolution.

“We find that capuchin monkeys eat embedded insects year-round but intensify their feeding seasonally, during the time that their preferred food — ripe fruit — is less abundant,” Melin said. “These results suggest embedded insects are an important fallback food.”

Previous research has shown that fallback foods help shape the evolution of primate body forms, including the development of strong jaws, thick teeth and specialized digestive systems in primates whose fallback diets rely mainly on vegetation.

This study suggests that fallback foods can also play an important role in shaping brain evolution among primates that fall back on insect-based diets, and that this influence is most pronounced among primates that evolve in habitats with wide seasonal variations, such as the wet-dry cycles found in some South American forests.

“Capuchin monkeys are excellent models for examining evolution of brain size and intelligence for their small body size, they have impressively large brains,” Melin said. “Accessing hidden and well-protected insects living in tree branches and under bark is a cognitively demanding task, but provides a high-quality reward: fat and protein, which is needed to fuel big brains.”

But when it comes to using tools, not all capuchin monkey strains and lineages are created equal, and Melin’s theories may explain why.

Perhaps the most notable difference between the robust (tufted, genus Sapajus) and gracile (untufted, genus Cebus) capuchin lineages is their variation in tool use. While Cebus monkeys are known for clever food-foraging tricks, such as banging snails or fruits against branches, they can’t hold a stick to their Sapajus cousins when it comes to theinnovative use and modification of sophisticated tools.

One explanation, Melin said, is that Cebus capuchins have historically and consistently occupied tropical rainforests, whereas the Sapajus lineage spread from their origins in the Atlantic rainforest into drier, more temperate and seasonal habitat types.

“Primates who extract foods in the most seasonal environments are expected to experience the strongest selection in the ‘sensorimotor intelligence’ domain, which includes cognition related to object handling,” Melin said. “This may explain the occurrence of tool use in some capuchin lineages, but not in others.”

Genetic analysis of mitochondial chromosomes suggests that the Sapajus-Cebus diversification occurred millions of years ago in the late Miocene epoch.

“We predict that the last common ancestor of Cebus and Sapajus had a level of SMI more closely resembling extant Cebus monkeys, and that further expansion of SMI evolved in the robust lineage to facilitate increased access to varied embedded fallback foods,necessitated by more intense periods of fruit shortage,” she said.

One of the more compelling modern examples of this behavior, said Melin, is the seasonal consumption of termites by chimpanzees, whose use of tools to extract this protein-rich food source is an important survival technique in harsh environments.

What does this all mean for hominids?

While it’s hard to decipher the extent of seasonal dietary variations from the fossil record, stable isotope analyses indicate seasonal variation in diet for at least one South African hominin, Paranthropus robustus. Other isotopic research suggests that early human diets may have included a range of extractable foods, such as termites, plant roots and tubers.

Modern humans frequently consume insects, which are seasonally important when other animal foods are limited.

This study suggests that the ingenuity required to survive on a diet of elusive insects has been a key factor in the development of uniquely human skills: It may well have been bugs that helped build our brains.

Journal Reference:

  1. Amanda D. Melin, Hilary C. Young, Krisztina N. Mosdossy, Linda M. Fedigan.Seasonality, extractive foraging and the evolution of primate sensorimotor intelligenceJournal of Human Evolution, 2014; 71: 77 DOI:10.1016/j.jhevol.2014.02.009

Stronger Brains, Weaker Bodies (New York Times)

Why does the metabolism of a sloth differ from that of a human? Brains are a big reason, say researchers who recently carried out a detailed comparison of metabolism in humans and other mammals. CreditFelipe Dana/Associated Press

All animals do the same thing to the food they eat — they break it down to extract fuel and building blocks for growing new tissue. But the metabolism of one species may be profoundly different from another’s. A sloth will generate just enough energy to hang from a tree, for example, while some birds can convert their food into a flight from Alaska to New Zealand.

For decades, scientists have wondered how our metabolism compares to that of other species. It’s been a hard question to tackle, because metabolism is complicated — something that anyone who’s stared at a textbook diagram knows all too well. As we break down our food, we produce thousands of small molecules, some of which we flush out of our bodies and some of which we depend on for our survival.

An international team of researchers has now carried out a detailed comparison of metabolism in humans and other mammals. As they report in the journal PLOS Biology, both our brains and our muscles turn out to be unusual, metabolically speaking. And it’s possible that their odd metabolism was part of what made us uniquely human.

When scientists first began to study metabolism, they could measure it only in simple ways. They might estimate how many calories an animal burned in a day, for example. If they were feeling particularly ambitious, they might try to estimate how many calories each organ in the animal’s body burned.

Those tactics were enough to reveal some striking things about metabolism. Compared with other animals, we humans have ravenous brains. Twenty percent of the calories we take in each day are consumed by our neurons as they send signals to one another.

Ten years ago, Philipp Khaitovich of the Max Planck Institute of Evolutionary Anthropology and his colleagues began to study human metabolism in a more detailed way. They started making a catalog of the many molecules produced as we break down food.

“We wanted to get as much data as possible, just to see what happened,” said Dr. Khaitovich.

To do so, the scientists obtained brain, muscle and kidney tissues from organ donors. They then extracted metabolic compounds like glucose from the samples and measured their concentrations. All told, they measured the levels of over 10,000 different molecules.

The scientists found that each tissue had a different metabolic fingerprint, with high levels of some molecules and low levels of others.

These distinctive fingerprints came as little surprise, since each tissue has a different job to carry out. Muscles need to burn energy to generate mechanical forces, for example, while kidney cells need to pull waste out of the bloodstream.

The scientists then carried out the same experiment on chimpanzees, monkeys and mice. They found that the metabolic fingerprint for a given tissue was usually very similar in closely related species. The same tissues in more distantly related species had fingerprints with less in common.

But the scientists found two exceptions to this pattern.

The first exception turned up in the front of the brain. This region, called the prefrontal cortex, is important for figuring out how to reach long-term goals. Dr. Khaitovich’s team found that the way the human prefrontal cortex uses energy is quite distinct from other species; other tissues had comparable metabolic fingerprints across species, and even in other regions of the brain, the scientists didn’t find such a drastic difference.

This result fit in nicely with findings by other scientists that the human prefrontal cortex expanded greatly over the past six million years of our evolution. Its expansion accounts for much of the extra demand our brains make for calories.

The evolution of our enormous prefrontal cortex also had a profound effect on our species. We use it for many of the tasks that only humans can perform, such as reflecting on ourselves, thinking about what others are thinking and planning for the future.

But the prefrontal cortex was not the only part of the human body that has experienced a great deal of metabolic evolution. Dr. Khaitovich and his colleagues found that the metabolic fingerprint of muscle is even more distinct in humans.

“Muscle was really off the charts,” Dr. Khaitovich said. “We didn’t expect to see that at all.”

It was possible that the peculiar metabolism in human muscle was just the result of our modern lifestyle — not an evolutionary shift in our species. Our high-calorie diet might change the way muscle cells generated energy. It was also possible that a sedentary lifestyle made muscles weaker, creating a smaller metabolic demand.

To test that possibility, Dr. Khaitovich compared the strength of humans to that of our closest relatives. They found that chimpanzees and monkeys are far stronger, for their weight, than even university basketball players or professional climbers.

The scientists also tested their findings by putting monkeys on a couch-potato regime for a month to see if their muscles acquired a human metabolic fingerprint.

They barely changed.

Dr. Khaitovich suspects that the metabolic fingerprint of our muscles represents a genuine evolutionary change in our species.

Karen Isler and Carel van Schaik of the University of Zurich have argued that the gradual changes in human brains and muscles were intimately linked. To fuel a big brain, our ancestors had to sacrifice other tissues, including muscles.

Dr. Isler said that the new research fit their hypothesis nicely. “It looks quite convincing,” she said.

Daniel E. Lieberman, a professor of human evolutionary biology at Harvard, said he found Dr. Khaitovich’s study “very cool,” but didn’t think the results meant that brain growth came at the cost of strength. Instead, he suggested, our ancestors evolved muscles adapted for a new activity: long-distance walking and running.

“We have traded strength for endurance,” he said. And that endurance allowed our ancestors to gather more food, which could then fuel bigger brains.

“It may be that the human brain is bigger not in spite of brawn but rather because of brawn, albeit a very different kind,” he said.

What gave us the advantage over extinct types of humans? (The Hebrew University of Jerusalem)

22-Apr-2014

Jerry Barach

The answer lies in changes in the way our genes work

Jerusalem, April 22, 2014 — In parallel with modern man (Homo sapiens), there were other, extinct types of humans with whom we lived side by side, such as Neanderthals and the recently discovered Denisovans of Siberia. Yet only Homo sapiens survived. What was it in our genetic makeup that gave us the advantage?

The truth is that little is known about our unique genetic makeup as distinguished from our archaic cousins, and how it contributed to the fact that we are the only species among them to survive. Even less is known about our unique epigenetic makeup, but it is exactly such epigenetic changes that may have shaped our own species.

While genetics deals with the DNA sequence itself and the heritable changes in the DNA (mutations), epigenetics deals with heritable traits that are not caused by mutations. Rather, chemical modifications to the DNA can efficiently turn genes on and off without changing the sequence. This epigenetic regulatory layer controls where, when and how genes are activated, and is believed to be behind many of the differences between human groups.

Indeed, many epigenetic changes distinguish us from the Neanderthal and the Denisovan, researchers at the Hebrew University of Jerusalem and Europe have now shown.

In an article just published in Science, Dr. Liran Carmel, Prof. Eran Meshorer and David Gokhman of the Alexander Silberman Institute of Life sciences at the Hebrew University, along with scientists from Germany and Spain, have reconstructed, for the first time, the epigenome of the Neanderthal and the Denisovan. Then, by comparing this ancient epigenome with that of modern humans, they identified genes whose activity had changed only in our own species during our most recent evolution.

Among those genetic pattern changes, many are expressed in brain development. Numerous changes were also observed in the immune and cardiovascular systems, whereas the digestive system remained relatively unchanged.

On the negative side, the researchers found that many of the genes whose activity is unique to modern humans are linked to diseases like Alzheimer’s disease, autism and schizophrenia, suggesting that these recent changes in our brain may underlie some of the psychiatric disorders that are so common in humans today.

By reconstructing how genes were regulated in the Neanderthal and the Denisovan, the researchers provide the first insight into the evolution of gene regulation along the human lineage and open a window to a new field that allows the studying of gene regulation in species that went extinct hundreds of thousands of years ago.

 

Human ‘missing link’ fossils may be jumble of species (New Scientist)

09 April 2014 by Colin Barras

Magazine issue 2964

Identity crisis <i>(Image: Benedicte Kurzen/The New York Times/Eyevine)</i>

Identity crisis (Image: Benedicte Kurzen/The New York Times/Eyevine)

ONE of our closest long-lost relatives may never have existed. The fossils ofAustralopithecus sediba, which promised to rewrite the story of human evolution, may actually be the remains of two species jumbled together.

The first fossils of A. sediba were found at Malapa, South Africa, in 2008. At 2 million years old, they show a mix of features, some similar to the ape-like australopithecines, others more like our genus, Homo. To its discoverers, this hotchpotch means A. sediba was becoming human, and that the Homogenus first evolved in South Africa, not east Africa as is generally thought.

But a new analysis suggests A. sediba didn’t exist. “I think there are two different hominin genera represented at Malapa,” says Ella Been at Tel Aviv University in Israel. One is an Australopithecus and one an early Homo. We can’t yet tell if the australopithecine remains are distinct enough to call them a new species, Been says.

Been studies the spinal columns of ancient hominins, so she was curious when a paper was published last year focusing on the spine of A. sediba(Science, doi.org/r7k). There are fragments from two skeletons at Malapa, a juvenile male and an adult female. Looking at photographs of the vertebrae, she noticed familiar features on the young male.

“I realised they looked a lot like the vertebrae of the Nariokotome Boy,” she says. Also known as Turkana Boy, this is a 1.5-million-year-old skeleton ofHomo erectus, a widespread species that may be our direct ancestor. Its vertebrae, like ours, are much wider than they are tall.

In contrast, the adult female’s vertebrae are taller, says Been, a classicAustralopithecus feature. She concludes that the spines belong to two different species.

When Been shared her findings with Yoel Rak, also at Tel Aviv University, she found an ally. “He sees the same in the [lower jawbone]: an australopithecine and an early Homo,” says Been. But here the species are switched: a notch in the young male jaw looks like Australopithecus, while the same notch in the adult female jaw looks human.

The pair conclude that there are not two but four individuals in the remains from Malapa: an adult and a juvenile of both Homo and Australopithecus. They presented their findings at a meeting of the Paleoanthropology Society in Calgary, Canada, this week.

Unsurprisingly, A. sediba‘s discoverer, Lee Berger of the University of Witwatersrand in South Africa, doesn’t agree. For one thing, he says the positioning of the adult skeleton’s bones in the ground makes it likely they came from a single individual.

Berger admits that the vertebrae of the young A. sediba look like those of H. erectus, but he says vertebrae grow taller throughout childhood. If the youngA. sediba had grown up, his vertebrae may have become moreAustralopithecus-like.

Been isn’t convinced. Fossils of other australopithecine children had tall vertebrae, she says.

Regardless, Berger says that Been and Rak’s observations make sense if A. sediba really was a transitional species between Australopithecus and Homo. “A central tenet of evolutionary theory is that variation within taxa becomes variation between taxa as species diverge,” he says. With anatomy in flux, it is possible that one A. sediba had an Australopithecus-like spine and Homo-like jaw, while another had a Homo-like spine and Australopithecus-like jaw.

There are other features of the A. sediba vertebrae that might explain the differences Been found. Berger’s latest work hints that the young male’s vertebrae may show signs of disease. If so, they are not representative of the species.

This article appeared in print under the headline “Missing link fossils may be a jumble of species”

The Mammoth Cometh (New York Times Magazine)

Bringing extinct animals back to life is really happening — and it’s going to be very, very cool. Unless it ends up being very, very bad.

By NATHANIEL RICHFEB. 27, 2014

Photo

CreditStephen Wilkes for The New York Times; Woolly Mammoth, Royal BC Museum, Victoria, British Columbia

The first time Ben Novak saw a passenger pigeon, he fell to his knees and remained in that position, speechless, for 20 minutes. He was 16. At 13, Novak vowed to devote his life to resurrecting extinct animals. At 14, he saw a photograph of a passenger pigeon in an Audubon Society book and “fell in love.” But he didn’t know that the Science Museum of Minnesota, which he was then visiting with a summer program for North Dakotan high-school students, had them in their collection, so he was shocked when he came across a cabinet containing two stuffed pigeons, a male and a female, mounted in lifelike poses. He was overcome by awe, sadness and the birds’ physical beauty: their bright auburn breasts, slate-gray backs and the dusting of iridescence around their napes that, depending on the light and angle, appeared purple, fuchsia or green. Before his chaperones dragged him out of the room, Novak snapped a photograph with his disposable camera. The flash was too strong, however, and when the film was processed several weeks later, he was haunted to discover that the photograph hadn’t developed. It was blank, just a flash of white light.

In the decade since, Novak has visited 339 passenger pigeons — at the Burke Museum in Seattle, the Carnegie Museum of Natural History in Pittsburgh, the American Museum of Natural History in New York and Harvard’s Ornithology Department, which has 145 specimens, including eight pigeon corpses preserved in jars of ethanol, 31 eggs and a partly albino pigeon. There are 1,532 passenger-pigeon specimens left on Earth. On Sept. 1, 1914, Martha, the last captive passenger pigeon, died at the Cincinnati Zoo. She outlasted George, the penultimate survivor of her species and her only companion, by four years. As news spread of her species’ imminent extinction, Martha became a minor tourist attraction. In her final years, whether depressed or just old, she barely moved. Underwhelmed zoo visitors threw fistfuls of sand at her to elicit a reaction. When she finally died, her body was taken to the Cincinnati Ice Company, frozen in a 300-pound ice cube and shipped by train to the Smithsonian Institution, where she was stuffed and mounted and visited, 99 years later, by Ben Novak.

The fact that we can pinpoint the death of the last known passenger pigeon is one of many peculiarities that distinguish the species. Many thousands of species go extinct every year, but we tend to be unaware of their passing, because we’re unaware of the existence of most species. The passenger pigeon’s decline was impossible to ignore, because as recently as the 1880s, it was the most populous vertebrate in North America. It made up as much as 40 percent of the continent’s bird population. In “A Feathered River Across the Sky,” Joel Greenberg suggests that the species’ population “may have exceeded that of every other bird on earth.” In 1860, a naturalist observed a single flock that he estimated to contain 3,717,120,000 pigeons. By comparison, there are currently 260 million rock pigeons in existence. A single passenger-pigeon nesting ground once occupied an area as large as 850 square miles, or 37 Manhattans.

The species’ incredible abundance was an enticement to mass slaughter. The birds were hunted for their meat, which was sold by the ton (at the higher end of the market, Delmonico’s served pigeon cutlets); for their oil and feathers; and for sport. Even so, their rapid decline — from approximately five billion to extinction within a few decades — baffled most Americans. Science magazine published an article claiming that the birds had all fled to the Arizona desert. Others hypothesized that the pigeons had taken refuge in the Chilean pine forests or somewhere east of Puget Sound or in Australia. Another theory held that every passenger pigeon had joined a single megaflock and disappeared into the Bermuda Triangle.

Stewart Brand, who was born in Rockford, Ill., in 1938, has never forgotten the mournful way his mother spoke about passenger pigeons when he was a child. During summers, the Brands vacationed near the top of Michigan’s mitten, not far from Pigeon River, one of the hundreds of American places named after the species. (Michigan alone has four Pigeon Rivers, four Pigeon Lakes, two Pigeon Creeks, Pigeon Cove, Pigeon Hill and Pigeon Point). Old-timers told stories about the pigeon that to Brand assumed a mythic quality. They said that the flocks were so large they blotted out the sun.

Brand’s compassion for the natural world has taken many diverse forms, but none more broadly influential than the Whole Earth Catalog, which he founded in 1968 and edited until 1984. Brand has said that the catalog, a dense compendium of environmentalist tools and practices, among other things, “encouraged individual power.” As it turned out, Whole Earth’s success gave Brand more power than most individuals, allowing him intimate access to the world’s most imaginative thinkers and patrons wealthy enough to finance those thinkers’ most ambitious ideas. In the last two decades, several of these ideas have materialized under the aegis of the Long Now Foundation, a nonprofit organization that Brand helped to establish in 1996 to support projects designed to inspire “long-term responsibility.” Among these projects are a 300-foot-tall clock designed to tick uninterruptedly for the next 10,000 years, financed by a $42 million investment from the Amazon.com founder Jeff Bezos and situated inside an excavated mountain that Bezos owns near Van Horn, Tex.; and a disk of pure nickel inscribed with 1,500 languages that has been mounted on the Rosetta space probe, which this year is scheduled to land on Comet 67P/Churyumov-Gerasimenko, 500 million miles from earth.

Three years ago Brand invited the zoologist Tim Flannery, a friend, to speak at Long Now’s Seminar About Long-Term Thinking, a monthly series held in San Francisco. The theme of the talk was “Is Mass Extinction of Life on Earth Inevitable?” In the question-and-answer period that followed, Brand, grasping for a silver lining, mentioned a novel approach to ecological conservation that was gaining wider public attention: the resurrection of extinct species, like the woolly mammoth, aided by new genomic technologies developed by the Harvard molecular biologist George Church. “It gives people hope when rewilding occurs — when the wolves come back, when the buffalo come back,” Brand said at the seminar. He paused. “I suppose we could get passenger pigeons back. I hadn’t thought of that before.”

‘One or two mammoths is not a success. 100,000 mammoths is a success.’ – STEWART BRAND

Brand became obsessed with the idea. Reviving an extinct species was exactly the kind of ambitious, interdisciplinary and slightly loopy project that appealed to him. Three weeks after his conversation with Flannery, Brand sent an email to Church and the biologist Edward O. Wilson:

Dear Ed and George . . .

The death of the last passenger pigeon in 1914 was an event that broke the public’s heart and persuaded everyone that extinction is the core of humanity’s relation with nature.

George, could we bring the bird back through genetic techniques? I recall chatting with Ed in front of a stuffed passenger pigeon at the Comparative Zoology Museum [at Harvard, where Wilson is a faculty emeritus], and I know of other stuffed birds at the Smithsonian and in Toronto, presumably replete with the requisite genes. Surely it would be easier than reviving the woolly mammoth, which you have espoused.

The environmental and conservation movements have mired themselves in a tragic view of life. The return of the passenger pigeon could shake them out of it — and invite them to embrace prudent biotechnology as a Green tool instead of menace in this century. . . . I would gladly set up a nonprofit to fund the passenger pigeon revival. . . .

Wild scheme. Could be fun. Could improve things. It could, as they say, advance the story.

Photo

Passenger Pigeon Extinct 1914. Billions of the pigeons were alive just a few decades earlier. Like the other animals shown here, it has been proposed for de-extinction projects. Credit Stephen Wilkes for The New York Times. Passenger pigeon, Museum of Comparative Zoology, Harvard University.

What do you think?

In less than three hours, Church responded with a detailed plan to return “a flock of millions to billions” of passenger pigeons to the planet.

In February 2012, Church hosted a symposium at Harvard Medical School called “Bringing Back the Passenger Pigeon.” Church gave a demonstration of his new genome-editing technology, and other biologists and avian specialists expressed enthusiasm for the idea. “De-extinction went from concept to potential reality right before our eyes,” said Ryan Phelan, Brand’s wife, an entrepreneur who founded an early consumer medical-genetics company. “We realized that we could do it not only for the passenger pigeon, but for other species. There was so much interest and so many ideas that we needed to create an infrastructure around it. It was like, ‘Oh, my God, look at what we’ve unleashed.’ ” Phelan, 61, became executive director of the new project, which they named Revive & Restore.

Several months later, the National Geographic Society hosted a larger conference to debate the scientific and ethical questions raised by the prospect of “de-extinction.” Brand and Phelan invited 36 of the world’s leading genetic engineers and biologists, among them Stanley Temple, a founder of conservation biology; Oliver Ryder, director of the San Diego Zoo’s Frozen Zoo, which stockpiles frozen cells of endangered species; and Sergey Zimov, who has created an experimental preserve in Siberia called Pleistocene Park, which he hopes to populate with woolly mammoths.

To Brand’s idea that the pigeon project would provide “a beacon of hope for conservation,” conference attendees added a number of ecological arguments in support of de-extinction. Just as the loss of a species decreases the richness of an ecosystem, the addition of new animals could achieve the opposite effect. The grazing habits of mammoths, for instance, might encourage the growth of a variety of grasses, which could help to protect the Arctic permafrost from melting — a benefit with global significance, as the Arctic permafrost contains two to three times as much carbon as the world’s rain forests. “We’ve framed it in terms of conservation,” Brand told me. “We’re bringing back the mammoth to restore the steppe in the Arctic. One or two mammoths is not a success. 100,000 mammoths is a success.”

A less scientific, if more persuasive, argument was advanced by the ethicist Hank Greely and the law professor Jacob Sherkow, both of Stanford. De-extinction should be pursued, they argued in a paper published in Science, because it would be really cool. “This may be the biggest attraction and possibly the biggest benefit of de-extinction. It would surely be very cool to see a living woolly mammoth.”

‘I appreciated his devotion to the bird, but I worried that his zeal might interfere with his ability to do serious science.’ – BETH SHAPIRO

Ben Novak needed no convincing. When he heard that Revive & Restore had decided to resurrect the passenger pigeon, he sent an email to Church, who forwarded it to Brand and Phelan. “Passenger pigeons have been my passion in life for a very long time,” Novak wrote. “Any way I can be part of this work would be my honor.”

Behind the biohazard signs and double-encoded security doors that mark the entrance of the paleogenomics lab at the University of California, Santa Cruz, I found no mastodon tusks, dinosaur eggs or mosquitoes trapped in amber — only a sterile, largely empty room in which Novak and several graduate students were busy checking their Gmail accounts. The only visible work in progress was Metroplex, a giant Transformers figurine that Novak constructed, which was hunched over his keyboard like a dead robot.

Novak, who is 27, hastened to assure me that the construction of the passenger-pigeon genome was also underway. In fact, it had been for years. Beth Shapiro, one of the scientists who runs the lab, began to sequence the species’ DNA in 2001, a decade before Brand had his big idea. The sequencing process is now in its data-analysis phase, which leaves Novak, who studied ecology in college, but has no advanced scientific degrees, time to consult on academic papers about de-extinction, write his own paper about the ecological relationship between passenger pigeons and chestnut trees and correspond with the scientists behind the world’s other species-resurrection efforts. These include the Uruz project, which is selectively breeding cattle to create a new subspecies that resembles aurochs, a form of wild ox, extinct since 1627; a group hoping to use genetic methods to revive the heath hen, extinct since 1932; and the Lazarus Project, which is trying to revive an Australian frog, extinct for 30 years, that gave birth through its mouth.

As Brand and Phelan’s only full-time employee at Revive & Restore, Novak fields emails sent by scientists eager to begin work on new candidates for de-extinction, like the California grizzly bear, the Carolina parakeet, the Tasmanian tiger, Steller’s sea cow and the great auk, which hasn’t been seen since 1844, when the last two known members of its species were strangled by Icelandic fishermen. Because de-extinction requires collaboration from a number of different disciplines, Phelan sees Revive & Restore as a “facilitator,” helping to connect geneticists, molecular biologists, synthetic biologists and conservation biologists. She also hopes that Revive & Restore’s support will enable experimental projects to proceed. She and Novak realize that the new discipline of de-extinction will advance regardless of their involvement, but, she says, “We just want it to happen responsibly.”

When Novak joined Shapiro’s lab, he knew nothing about Santa Cruz and nobody there. A year later, apart from an occasional dinner on the Brands’ tugboat in Sausalito, little has changed. Novak is largely left alone with his thoughts and his dead animals. But it has always been this way for Novak, who grew up in a house three miles from his closest neighbor, halfway between Williston, the eighth-largest city in North Dakota, and Alexander, which has a population of 269. As a boy, Novak often took solitary hikes through the badlands near his home, exploring a vast petrified forest that runs through the Sentinel Butte formation. Fifty million years ago, that part of western North Dakota resembled the Florida Everglades. Novak frequently came across vertebrae, phalanges and rib fragments of extinct crocodiles and champsosaurs.

This was two hours north of Elkhorn Ranch, where Theodore Roosevelt developed the theories about wildlife protection that led to the preservation of 230 million acres of land. The local schools emphasized conservation in their science classes. In sixth grade, Novak was astonished to learn that he was living in the middle of a mass extinction. (Scientists predict that changes made by human beings to the composition of the atmosphere could kill off a quarter of the planet’s mammal species, a fifth of its reptiles and a sixth of its birds by 2050.) “I felt a certain amount of solidarity with these species,” he told me. “Maybe because I spent so much time alone.”

Photo

Great Auk Not seen since 1844, when Icelandic fishermen strangled the last known survivors. Credit Stephen Wilkes for The New York Times. Great Auk, Museum of Comparative Zoology, Harvard University.

After graduating from Montana State University in Bozeman, Novak applied to study under Beth Shapiro, who had already begun to sequence passenger-pigeon DNA. He was rejected. “I appreciated his devotion to the bird,” she told me, “but I worried that his zeal might interfere with his ability to do serious science.” Novak instead entered a graduate program at the McMaster Ancient DNA Center in Hamilton, Ontario, where he worked on the sequencing of mastodon DNA. But he remained obsessed by passenger pigeons. He decided that, if he couldn’t join Shapiro’s lab, he would sequence the pigeon’s genome himself. He needed tissue samples, so he sent letters to every museum he could find that possessed the stuffed specimens. He was denied more than 30 times before Chicago’s Field Museum sent him a tiny slice of a pigeon’s toe. A lab in Toronto conducted the sequencing for a little more than $2,500, which Novak raised from his family and friends. He had just begun to analyze the data when he learned about Revive & Restore.

After Novak was hired, Shapiro offered him office space at the U.C.S.C. paleogenomics lab, where he could witness the sequencing work as it happened. Now, when asked what he does for a living, Novak says that his job is to resurrect the passenger pigeon.

Novak is tall, solemn, polite and stiff in conversation, until the conversation turns to passenger pigeons, which it always does. One of the few times I saw him laugh was when I asked whether de-extinction might turn out to be impossible. He reminded me that it has already happened. More than 10 years ago, a team that included Alberto Fernández-Arias (now a Revive & Restore adviser) resurrected a bucardo, a subspecies of mountain goat also known as the Pyrenean ibex, that went extinct in 2000. The last surviving bucardo was a 13-year-old female named Celia. Before she died — her skull was crushed by a falling tree — Fernández-Arias extracted skin scrapings from one of her ears and froze them in liquid nitrogen. Using the same cloning technology that created Dolly the sheep, the first cloned mammal, the team used Celia’s DNA to create embryos that were implanted in the wombs of 57 goats. One of the does successfully brought her egg to term on July 30, 2003. “To our knowledge,” wrote the scientists, “this is the first animal born from an extinct subspecies.” But it didn’t live long. After struggling to breathe for several minutes, the kid choked to death.

This cloning method, called somatic cell nuclear transfer, can be used only on species for which we have cellular material. For species like the passenger pigeon that had the misfortune of going extinct before the advent of cryopreservation, a more complicated process is required. The first step is to reconstruct the species’ genome. This is difficult, because DNA begins to decay as soon as an organism dies. The DNA also mixes with the DNA of other organisms with which it comes into contact, like fungus, bacteria and other animals. If you imagine a strand of DNA as a book, then the DNA of a long-dead animal is a shuffled pile of torn pages, some of the scraps as long as a paragraph, others a single sentence or just a few words. The scraps are not in the right order, and many of them belong to other books. And the book is an epic: The passenger pigeon’s genome is about 1.2 billion base pairs long. If you imagine each base pair as a word, then the book of the passenger pigeon would be four million pages long.

There is a shortcut. The genome of a closely related species will have a high proportion of identical DNA, so it can serve as a blueprint, or “scaffold.” The passenger pigeon’s closest genetic relative is the band-tailed pigeon, which Shapiro is now sequencing. By comparing the fragments of passenger-pigeon DNA with the genomes of similar species, researchers can assemble an approximation of an actual passenger-pigeon genome. How close an approximation, it will be impossible to know. As with any translation, there may be errors of grammar, clumsy phrases and perhaps a few missing passages, but the book will be legible. It should, at least, tell a good story.

Shapiro hopes to complete this part of the process in the coming months. At that point, the researchers will have, on their hard drives, a working passenger-pigeon genome. If you opened the file on a computer screen, you would see a chain of 1.2 billion letters, all of them A, G, C or T. Shapiro hopes to publish an analysis of the genome by Sept. 1, in time for the centenary of Martha’s death.

Photo

Woolly Mammoth Became extinct about 4,000 years ago. Credit Stephen Wilkes for The New York Times; Woolly Mammoth, Royal BC Museum, Victoria, British Columbia

That, unfortunately, is the easy part. Next the genome will have to be inscribed into a living cell. This is even more complicated than it sounds. Molecular biologists will begin by trying to culture germ cells from a band-tailed pigeon. Cell culturing is the process by which living tissue is made to grow in a petri dish. Bird cells can be especially difficult to culture. They strongly prefer not to exist outside of a body. “For birds,” Novak said, “this is the hump to get over.” But it is largely a question of trial and error — a question, in other words, of time, which Revive & Restore has in abundance.

Should scientists succeed in culturing a band-tailed-pigeon germ cell, they will begin to tinker with its genetic code. Biologists describe this as a “cut-and-paste job.” They will replace chunks of band-tailed-pigeon DNA with synthesized chunks of passenger-pigeon DNA, until the cell’s genome matches their working passenger-pigeon genome. They will be aided in this process by a fantastical new technology, invented by George Church, with the appropriately runic name of MAGE (Multiplex Automated Genome Engineering). MAGE is nicknamed the “evolution machine” because it can introduce the equivalent of millions of years of genetic mutations within minutes. After MAGE works its magic, scientists will have in their petri dishes living passenger-pigeon cells, or at least what they will call passenger-pigeon cells.

The biologists would next introduce these living cells into a band-tailed-pigeon embryo. No hocus-pocus is involved here: You chop off the top of a pigeon egg, inject the passenger-pigeon cells inside and cover the hole with a material that looks like Saran wrap. The genetically engineered germ cells integrate into the embryo; into its gonads, to be specific. When the chick hatches, it should look and act like a band-tailed pigeon. But it will have a secret. If it is a male, it carries passenger-pigeon sperm; if it is a female, its eggs are passenger-pigeon eggs. These creatures — band-tailed pigeons on the outside and passenger pigeons on the inside — are called “chimeras” (from the Middle English for “wild fantasy”). Chimeras would be bred with one another in an effort to produce passenger pigeons. Novak hopes to observe the birth of his first passenger-pigeon chick by 2020, though he suspects 2025 is more likely.

At that point, the de-extinction process would move from the lab to the coop. Developmental and behavioral biologists would take over, just in time to answer some difficult questions. Chicks imitate their parents’ behavior. How do you raise a passenger pigeon without parents of its own species? And how do you train band-tailed pigeons to nurture the strange spawn that emerge from their eggs; chicks that, to them, might seem monstrous: an avian Rosemary’s Baby?

Despite the genetic similarity between the two pigeon species, significant differences remain. Band-tailed pigeons are a western bird and migrate vast distances north and south; passenger pigeons lived in the eastern half of the continent and had no fixed migration patterns. In order to ease the transition between band-tailed parents and passenger chicks, a Revive & Restore partner will soon begin to breed a flock of band-tailed pigeons to resemble passenger pigeons. They will try to alter the birds’ diets, migration habits and environment. The behavior of each subsequent generation will more closely resemble that of their genetic cousins. “Eventually,” Novak said, “we’ll have band-tailed pigeons that are faux-passenger-pigeon parents.” As unlikely as this sounds, there is a strong precedent; surrogate species have been used extensively in pigeon breeding.

During the breeding process, small modifications would be made to the genome in order to ensure genetic diversity within the new population. After three to five years, some of the birds would be moved to a large outdoor aviary, where they would be exposed to nature for the first time: trees, weather, bacteria. Small-population biologists will be consulted, as will biologists who study species reintroduction. Other animals would gradually be introduced into the aviary, one at a time. The pigeons would be transferred between aviaries to simulate their hopscotching migratory patterns. Ecologists will study how the birds affect their environment and are affected by it. After about 10 years, some of the birds in the aviary would be set free into the wild, monitored by G.P.S. chips implanted under their skin. The project will be considered a full success when the population in the wild is capable of perpetuating itself without the addition of new pigeons from the aviary. Novak expects this to occur as early as 25 years after the first birds are let into the wild, or 2060. And he hopes that he will be there to witness it.

‘Nature makes monsters. Nature makes threats. Many of the things that are most threatening to us are a product of nature.’ – DAVID HAUSSLER

While Novak’s pigeons are reproducing, Revive & Restore will have embarked on a parallel course with a number of other species, both extinct and endangered. Besides the woolly mammoth, candidates include the black-footed ferret, the Caribbean monk seal, the golden lion tamarin, the ivory-billed woodpecker and the northern white rhinoceros, a species that is down to its final handful of members. For endangered species with tiny populations, scientists would introduce genetic diversity to offset inbreeding. For species threatened by contagion, an effort would be made to fortify their DNA with genes that make them disease-resistant. Millions of North American bats have died in the past decade from white-nose syndrome, a disease named after a deadly fungus that was likely imported from Europe. Many European bat species appear to be immune to the fungus; if the gene responsible for this immunity is identified, one theory holds that it could be synthesized and injected into North American bats. The scientific term for this type of genetic intervention is “facilitated adaptation.” A better name for Revive & Restore would be Revive & Restore & Improve.

This optimistic, soft-focus fantasy of de-extinction, while thrilling to Ben Novak, is disturbing to many conservation biologists, who consider it a threat to their entire discipline and even to the environmental movement. At a recent Revive & Restore conference and in articles appearing in both the popular and academic press since then, they have articulated their litany of criticisms at an increasingly high pitch. In response, particularly in recent months, supporters of de-extinction have more aggressively begun to advance their counterarguments. “We have answers for every question,” Novak told me. “We’ve been thinking about this a long time.”

The first question posed by conservationists addresses the logic of bringing back an animal whose native habitat has disappeared. Why go through all the trouble just to have the animal go extinct all over again? While this criticism is valid for some species, the passenger pigeon should be especially well suited to survive in new habitats, because it had no specific native habitat to begin with. It was an opportunistic eater, devouring a wide range of nuts and acorns and flying wherever there was food.

There is also anxiety about disease. “Pathogens in the environment are constantly evolving, and animals are developing new immune systems,” said Doug Armstrong, a conservation biologist in New Zealand who studies the reintroduction of species. “If you recreate a species genetically and release it, and that genotype is based on a bird from a 100-year-old environment, you probably will increase risk.” A revived passenger pigeon might be a vector for modern diseases. But this concern, said David Haussler, the co-founder of the Genome 10K Project, is overblown. “There’s always this fear that somehow, if we do it, we’re going to accidentally make something horrible, because only nature can really do it right. But nature is totally random. Nature makes monsters. Nature makes threats. Many of the things that are most threatening to us are a product of nature. Revive & Restore is not going to tip the balance in any way.” (Some scientists have speculated that, by competing for acorns with rodents and deer, the passenger pigeon could bring about a decrease in Lyme disease.)

More pressing to conservationists is a practical anxiety: Money. De-extinction is a flashy new competitor for patronage. As the conservationist David Ehrenfeld said at a Revive & Restore conference: “If it works, de-extinction will only target a very few species and is extremely expensive. Will it divert conservation dollars from tried-and-true conservation measures that already work, which are already short of funds?” This argument can be made for any conservation strategy, says the ecologist Josh Donlan, an adviser to Revive & Restore. “In my view,” Donlan wrote in a paper that is scheduled to be published in the forthcoming issue of Frontiers of Biogeography, “[the] conservation strategies are not mutually exclusive — a point conservation scientists tend to overlook.” So far this prediction has held up. Much of the money spent so far for sequencing the passenger-pigeon genome has been provided by Beth Shapiro’s U.C.S.C. research budget. Revive & Restore’s budget, which was $350,000 last year, has been raised largely from tech millionaires who are not known for supporting ecological causes.

De-extinction also poses a rhetorical threat to conservation biologists. The specter of extinction has been the conservation movement’s most powerful argument. What if extinction begins to be seen as a temporary inconvenience? The ecologist Daniel Simberloff raised a related concern. “It’s at best a technofix dealing with a few species,” he told me. “Technofixes for environmental problems are band-aids for massive hemorrhages. To the extent that the public, who will never be terribly well informed on the larger issue, thinks that we can just go and resurrect a species, it is extremely dangerous. . . . De-extinction suggests that we can technofix our way out of environmental issues generally, and that’s very, very bad.”

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The extinct heath hen, a candidate for resurrection. CreditStephen Wilkes for The New York Times. Heath hen: Museum of Comparative Zoology, Harvard University.

Ben Novak — who trails Simberloff in professional stature by a doctorate, hundreds of scientific publications and a pair of lifetime-achievement awards — rejects this view. “This is about an expansion of the field, not a reduction,” he says. “We get asked these big questions, but no one is asking people who work on elephants why they’re not working with giraffes, when giraffes need a lot more conservation work than elephants do. Nobody asks the people who work on rhinos why they aren’t working on the Arctic pollinators that are being devastated by climate change. The panda program rarely gets criticized, even though that project is completely pointless in the grand scheme of biodiversity on this planet, because the panda is a cute animal.” If the success of de-extinction, or even its failure, increases public awareness of the threats of mass extinction, Novak says, then it will have been a triumph.

How will we decide which species to resurrect? Some have questioned the logic of beginning with a pigeon. “Do you think that wealthy people on the East Coast are going to want billions of passenger pigeons flying over their freshly manicured lawns and just-waxed S.U.V.s?” asked Shapiro, whose involvement in the passenger-pigeon project will end once she finishes analyzing its genome. (She is writing a book about the challenges of de-extinction.) In an attempt to develop scientific criteria, the New Zealand zoologist Philip Seddon recently published a 10-point checklist to determine the suitability of any species for revival, taking into account causes of its extinction, possible threats it might face upon resurrection and man’s ability to destroy the species “in the event of unacceptable ecological or socioeconomic impacts.” If passenger pigeons, in other words, turn out to be an environmental scourge — if, following nature’s example, we create a monster — will we be able to kill them off? (The answer: Yes, we’ve done it before.)

But the most visceral argument against de-extinction is animal cruelty. Consider the 56 female mountain goats who were unable to bring to term the deformed bucardo embryos that were implanted in their wombs. Or the bucardo that was born and lived only a few minutes, gasping for breath, before dying of a lung deformity? “Is it fair to do this to these animals?” Shapiro asked. “Is ‘because we feel guilty’ a good-enough reason?” Stewart Brand made a utilitarian counterargument: “We’re going to go through some suffering, because you try a lot of times, and you get ones that don’t take. On the other hand, if you can bring bucardos back, then how many would get to live that would not have gotten to live?”

And, finally, what will the courts make of packs of woolly mammoths and millions of passenger pigeons let loose on the continent? In “How to Permit Your Mammoth,” published in The Stanford Environmental Law Journal, Norman F. Carlin asks whether revived species should be protected by the Endangered Species Act or regulated as a genetically modified organism. He concludes that revived species, “as products of human ingenuity,” should be eligible for patenting.

This question of “human ingenuity” approaches one of the least commented upon but most significant points about de-extinction. The term “de-extinction” is misleading. Passenger pigeons will not rise from the grave. Instead, band-tailed-pigeon DNA will be altered to resemble passenger-pigeon DNA. But we won’t know how closely the new pigeon will resemble the extinct pigeon until it is born; even then, we’ll only be able to compare physical characteristics with precision. Our understanding of the passenger pigeon’s behavior derives entirely from historical accounts. While many of these, including John James Audubon’s chapter on the pigeon in “Ornithological Biography,” are vividly written, few are scientific in nature. “There are a million things that you cannot predict about an organism just from having its genome sequence,” said Ed Green, a biomolecular engineer who works on genome-sequencing technology in the U.C.S.C. paleogenomics lab. Shapiro said: “It’s just one guess. And it’s not even a very good guess.”

Shapiro is no more sanguine about the woolly-mammoth project. “You’re never going to get a genetic clone of a mammoth,” she said. “What’s going to happen, I imagine, is that someone, maybe George Church, is going to insert some genes into the Asian-elephant genome that make it slightly hairier. That would be just a tiny portion of the genome manipulated, but a few years later, you have a thing born that is an elephant, only hairier, and the press will write, ‘George Church has cloned a mammoth!’ ” Church, though he plans to do more than just alter the gene for hairiness, concedes the point. “I would like to have an elephant that likes the cold weather,” he told me. “Whether you call it a ‘mammoth’ or not, I don’t care.”

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Tasmanian Tiger Also known as the thylacine, it was last spotted in Tasmania in 1930.CreditStephen Wilkes for The New York Times. Tasmanian Tiger, Mammalogy Department, American Museum of Natural History.

There is no authoritative definition of “species.” The most widely accepted definition describes a group of organisms that can procreate with one another and produce fertile offspring, but there are many exceptions. De-extinction operates under a different definition altogether. Revive & Restore hopes to create a bird that interacts with its ecosystem as the passenger pigeon did. If the new bird fills the same ecological niche, it will be successful; if not, back to the petri dish. “It’s ecological resurrection, not species resurrection,” Shapiro says. A similar logic informs the restoration of Renaissance paintings. If you visit “The Last Supper” in the refectory of the Convent of Santa Maria delle Grazie in Milan, you won’t see a single speck of paint from the brush of Leonardo da Vinci. You will see a mural with the same proportions and design as the original, and you may feel the same sense of awe as the refectory’s parishioners felt in 1498, but the original artwork disappeared centuries ago. Philosophers call this Theseus’ Paradox, a reference to the ship that Theseus sailed back to Athens from Crete after he had slain the Minotaur. The ship, Plutarch writes, was preserved by the Athenians, who “took away the old planks as they decayed, putting in new and stronger timber in their place.” Theseus’ ship, therefore, “became a standing example among the philosophers . . . one side holding that the ship remained the same, and the other contending that it was not the same.”

What does it matter whether Passenger Pigeon 2.0 is a real passenger pigeon or a persuasive impostor? If the new, synthetically created bird enriches the ecology of the forests it populates, few people, including conservationists, will object. The genetically adjusted birds would hardly be the first aspect of the deciduous forest ecosystem to bear man’s influence; invasive species, disease, deforestation and a toxic atmosphere have engineered forests that would be unrecognizable to the continent’s earliest European settlers. When human beings first arrived, the continent was populated by camels, eight-foot beavers and 550-pound ground sloths. “People grow up with this idea that the nature they see is ‘natural,’ ” Novak says, “but there’s been no real ‘natural’ element to the earth the entire time humans have been around.”

The earth is about to become a lot less “natural.” Biologists have already created new forms of bacteria in the lab, modified the genetic code of countless living species and cloned dogs, cats, wolves and water buffalo, but the engineering of novel vertebrates — of breathing, flying, defecating pigeons — will represent a milestone for synthetic biology. This is the fact that will overwhelm all arguments against de-extinction. Thanks, perhaps, to “Jurassic Park,” popular sentiment already is behind it. (“That movie has done a lot for de-extinction,” Stewart Brand told me in all earnestness.) In a 2010 poll by the Pew Research Center, half of the respondents agreed that “an extinct animal will be brought back.” Among Americans, belief in de-extinction trails belief in evolution by only 10 percentage points. “Our assumption from the beginning has been that this is coming anyway,” Brand said, “so what’s the most benign form it can take?”

What is coming will go well beyond the resurrection of extinct species. For millenniums, we have customized our environment, our vegetables and our animals, through breeding, fertilization and pollination. Synthetic biology offers far more sophisticated tools. The creation of novel organisms, like new animals, plants and bacteria, will transform human medicine, agriculture, energy production and much else. De-extinction “is the most conservative, earliest application of this technology,” says Danny Hillis, a Long Now board member and a prolific inventor who pioneered the technology that is the basis for most supercomputers. Hillis mentioned Marshall McLuhan’s observation that the content of a new medium is the old medium: that each new technology, when first introduced, recreates the familiar technology it will supersede. Early television shows were filmed radio shows. Early movies were filmed stage plays. Synthetic biology, in the same way, may gain widespread public acceptance through the resurrection of lost animals for which we have nostalgia. “Using the tool to recreate old things,” Hillis said, “is a much more comfortable way to get engaged with the power of the tool.”

“By the end of this decade we’ll seem incredibly conservative,” Brand said. “A lot of this stuff is going to become part of the standard tool kit. I would guess that within a decade or two, most of the major conservation organizations will have de-extinction as part of the portfolio of their activities.” He said he hoped to see the birth of a baby woolly mammoth in his lifetime. The opening line of the first Whole Earth Catalog was “We are as gods and might as well get good at it.” Brand has revised this motto to: “We are as gods and HAVE to get good at it.” De-extinction is a good way to practice.

A passion for bringing a lost pigeon back to life is hardly inconsistent with scientific inquiry. Ben Novak insists that he is motivated purely by ecological concerns. “To some people, it might be about making some crazy new pet or zoo animal, but that’s not our organization,” he told me. The scientists who work beside him in the paleogenomics lab — who hear his daily passenger-pigeon rhapsodies — suspect a second motivation. “I’m a biologist, I’ve seen people passionate about animals before,” Andre Soares, a young Brazilian member of Shapiro’s staff, said, “but I’ve never seen anyone this passionate.” He laughed. “It’s not like he ever saw the pigeon flying around. And it’s not like a dinosaur, a massive beast that walked around millions of years ago. No, it’s just a pigeon. I don’t know why he loves them so much.”

I repeated what Novak told me, that the passenger-pigeon project was “all under the framework of conservation.” Soares shook his head. “I think the birds are his thing,” he said.

Ed Green, the biomolecular engineer down the hall, was more succinct. “The passenger pigeon,” he said, “makes Ben want to write poetry.”

Nathaniel Rich is a contributing writer and the author, most recently, of “Odds Against Tomorrow,” a novel.

Editor: Jon Kelly