Arquivo da tag: Evolucionismo

Are Humans Still Evolving? Scientists Weigh In (Science Alert)

sciencealert.com

Eva Hamrud, Metafact – 20 Sept. 2020


As a species, humans have populated almost every corner of the earth. We have developed technologies and cultures which shape the world we live in.

The idea of ‘natural selection’ or ‘survival of the fittest’ seems to make sense in Stone Age times when we were fighting over scraps of meat, but does it still apply now?

We asked 12 experts whether humans are still evolving. The expert consensus is unanimously ‘yes’, however scientists say we might have the wrong idea of what evolution actually is.

Evolution is not the same as natural selection

Evolution is often used interchangeable with the phrases ‘survival of the fittest’ or ‘natural selection’. Actually, these are not quite the same thing.

‘Evolution’ simply means the gradual change of a population over time.

‘Natural selection’ is a mechanism by which evolution can occur. Our Stone Age ancestors who were faster runners avoided being trampled by mammoths and were more likely to have children. That is ‘natural selection’.

Overtime, the human population became faster at running. That’s evolution.

Evolution can happen without natural selection

That makes sense for Stone Age humans, but what about nowadays? We don’t need to outrun mammoths, we have medicines for when we’re sick and we can go to the shops to get food.

Natural selection needs a ‘selection pressure’ (e.g. dangerous trampling mammoths), so if we don’t have these anymore, does this mean we stop evolving?

Even with no selection pressures, experts say evolution still occurs by other mechanisms.

Professor Stanley Ambrose, an anthropologist from the University of Illinois, explains that “any change in the proportions of genes or gene variants over time is also considered evolution. The variants may be functionally equivalent, so evolution does not automatically equate with ‘improvement'”.

Whilst some genes can be affected by natural selection (e.g. genes that help us run faster), other changes in our DNA might have no obvious effect on us. ‘Neutral’ variations can also spread through a population by a different mechanism called ‘genetic drift’.

Genetic drift works by chance: some individuals might be unlucky and die for reasons which have nothing to do with their genes. Their unique gene variations will not be passed on to the next generation, and so the population will change.

Genetic drift doesn’t need any selection pressures, and it is still happening today.

Natural selection is still happening in humans

As much as we have made things easier for ourselves, there are still selection pressures around us, which mean that natural selection is still happening.

Like all mammals, humans lose the ability to digest milk when they stop breastfeeding. This is because we stop making an enzyme called lactase. In some countries, the population has acquired ‘lactase persistence’, meaning that people make lactase throughout their lives.

In European countries we can thank one specific gene variation for our lactase persistence, which is called ‘-13910*T’. By studying this specific gene variation in modern and ancient DNA samples, researchers suggest that it became common after humans started domesticated and milking animals.

This is an example of natural selection where we have actually made the selection pressure ourselves – we started drinking milk, so we evolved to digest it!

Another example of humans undergoing natural selection to adapt to a lifestyle is the Bajau people, who traditionally live in houseboats in the waters of South East Asia and spend much of their lives diving to hunt fish or collect shellfish.

Ultrasound imaging has found that Bajau people have larger spleens than their neighbours – an adaption which allows them to stay underwater for longer.

There are always selective pressures around us, even ones that we create ourselves.

As Dr Benjamin Hunt from the University of Birmingham puts it, “Our technological and cultural changes alter the strength and composition of the selection pressures within our environment, but selection pressures still exist.”

Evolution can’t be stopped

So, evolution can happen by different mechanisms like natural selection and genetic drift. As our environment is always changing, natural selection is always happening. And even if our environment was ‘just right’ for us, we would evolve anyway!

Dr Alywyn Scally, an expert in evolution and genetics from the University of Cambridge, explains: “As long as human reproduction involves randomness and genetic mutation (and the laws of the Universe pretty much guarantee that this will always be the case at some level), there will continue to be differences from one generation to the next, meaning that the process of evolution can never be truly halted.”

Takeaway: Evolution means change in a population. That includes both easy-to-spot changes to adapt to an environment as well as more subtle, genetic changes.

Humans are still evolving, and that is unlikely to change in the future.

Article based on 12 expert answers to this question: Are humans still evolving?

This expert response was published in partnership with independent fact-checking platform Metafact.io. Subscribe to their weekly newsletter here.

Carlos Guerra Schrago: Teoria e prática da evolução (Pesquisa Fapesp)

Disciplina que busca reconstituir as histórias das espécies está, ela própria, em mutação, de acordo com biólogo da UFRJ

Fabrício Marques e Maria Guimarães

Edição 291
mai. 2020

Em companhia de Charles Darwin no Museu de História Natural de Londres, em 2018. Arquivo pessoal

O biólogo Carlos Guerra Schrago, do Departamento de Genética da Universidade Federal do Rio de Janeiro (UFRJ), faz extensas análises de dados no computador, usa estatística e sequências genéticas. Assentado na teoria evolutiva, seu trabalho ajuda a entender aspectos da realidade, como os caminhos da disseminação de uma doença (a epidemia de zika a partir de 2015) e a diversificação de mamíferos, especialmente roedores e primatas.

A variedade de objetos de estudo é reveladora de como a mesma teoria pode ser aplicada a todos os organismos, com uma diferença importante: com uma vida efêmera enquanto indivíduos, microrganismos são capazes de perpetuar-se por meio de uma rápida multiplicação. Aos olhos de um evolucionista, reconstituir a trilha de modificações genéticas resultante dessa replicação se transforma praticamente em um filme que relata sua história.

Graduado em biologia na UFRJ com especialização em bioinformática no Laboratório Nacional de Computação Científica (LNCC), em Petrópolis, Guerra concluiu seu doutorado na UFRJ em 2004 e, entre 2018 e 2019, fez estágio de pós-doutorado na Universidade Harvard, nos Estados Unidos. Na entrevista a seguir, concedida por videoconferência, ele fala de mudanças pelas quais a teoria evolutiva vem passando e de como reage quando estudantes contestam a disciplina. Para ele, os pesquisadores caem em uma armadilha quando reagem como se houvesse um embate entre religião e ciência.

 Seu campo de estudo é a evolução viral. Como você vê a pandemia do novo coronavírus?
Ainda não analisei o material bruto do coronavírus, mas chamou a minha atenção que talvez tenha sido a primeira vez que a biologia evolutiva lidou com um problema prático novo, que é avaliar se uma sequência, seja um genoma de vírus ou de bactéria, foi manipulada em laboratório ou não. O trabalho que mostrou que o vírus Sars-CoV-2 não passou por manipulação, publicado em março na revista Nature Medicine, foi assinado por um grupo de virologistas moleculares que trabalham com evolução e teve uma repercussão considerável. É inclusive um problema geopolítico, porque saber se uma sequência teve ou não origem natural implica avaliar se foi objeto de bioterrorismo.

Esse tipo de trabalho também permite analisar a evolução molecular do vírus para traçar como ele está circulando e tentar fazer previsões…
Certamente para a vigilância epidemiológica de qualquer país é relevante saber o ritmo, a taxa de crescimento e de expansão das infecções e tentar traçar de onde esses vírus e sequências vieram. Mas o trabalho feito até agora carece de uma amostragem de sequências maior. É difícil fazer inferências sobre a dinâmica espacial e temporal de uma epidemia quando a amostragem é incompleta. Em relação ao Sars-CoV-2 circulante no Brasil, mostrou-se que são sequências de vírus originadas da Europa e EUA, mas o esforço de obter amostras não foi homogêneo em todos os países.

Talvez a seleção natural não seja a única explicação, mas ainda é a melhor que temos para entender a complexidade dos seres vivos

Seu laboratório trabalha com zika. Qual o alvo dos estudos?
Nossos questionamentos são teóricos e relacionados à epidemia de zika, e o que se aplica à zika vale para qualquer epidemia. As metodologias de bioinformática ou de evolução molecular são as mesmas. Nosso interesse era saber como se comportam parâmetros relevantes para quem trabalha com saúde pública, como a idade da epidemia, de onde ela veio, sua taxa de crescimento. Há uma quantidade enorme de pressupostos teóricos que queríamos avaliar e isso requer simulações computacionais bastante realistas. Nosso trabalho tem sido desenhar simuladores de crescimento e de dinâmica da epidemia, tentando aproximá-los da realidade do vírus no espaço e no tempo. Isso para avaliar a robustez de métodos tradicionalmente usados, por exemplo, para a reconstrução da história evolutiva do vírus ou cálculos da dinâmica espacial. Concluímos que alguns desses métodos têm problemas. Obtivemos valores mais precisos quando usamos as mudanças silenciosas no genoma, ou seja, mudanças no nível do DNA que não são passadas para o que é aparente, o fenótipo. As mudanças não silenciosas, aquelas que acarretam mudança de fato em alguma proteína que afeta um fenótipo, estão submetidas a regimes de seleção e são mais suscetíveis.

O trabalho envolve estatística e bioinformática. É possível explicar para um leigo como isso funciona?
Em publicações de divulgação científica ou mesmo em filmes de ficção científica, sempre aparecem sequências de DNA com aquelas letrinhas: A, C, T e G. São as bases nitrogenadas que se combinam para formar o DNA. Um dos desafios de quem trabalha com evolução molecular e genética é olhar essas letras, com diversas combinações e possibilidades, e tentar desvendar a história por trás delas. É como chegar na sua casa, olhar os cômodos e tentar descobrir o que aconteceu enquanto você estava ausente. Às vezes, é simples. Se você tem um cachorro e encontra tudo rasgado na sala, conclui: foi o cachorro. Mas em muitos casos requer a aplicação de modelos avançados. É algo comum do pensamento humano fazer inferências históricas. Entretanto, em biologia evolutiva é preciso estar respaldado por algo mais quantitativo. Na busca por uma comunicação objetiva, recorremos a inferências estatísticas que permitem quantificar mudanças na natureza. Nessa história, tratamos de tudo, de tempo, de quem é parente de quem, de onde veio, como chegou até aqui. Essas perguntas podem ser aplicadas a vírus, plantas, animais.

Como tem sido a evolução dessa metodologia? Como ela contribui para avançar o conhecimento?
A disciplina evolução molecular e filogenética surgiu na década de 1960, embora os conceitos com que trabalhamos sejam mais antigos – de uma história evolutiva compartilhada, de como a diversidade genética responde a regimes de seleção. Mas eles careciam de métodos mais algorítmicos para serem estudados e só foi possível chegar a esse patamar com o crescimento da utilização de computadores nas ciências naturais. Isso também dependeu do conhecimento sobre as sequências de nucleotídeos – e a estrutura do DNA só foi desvendada nos anos 1950. Até o aparecimento da disciplina, não se tinha ideia de como os genomas evoluíam. Com ela, o tema se tornou objeto de pesquisa e, utilizando dados moleculares, tornou-se possível reconstruir relações evolutivas entre várias espécies e ampliar o conhecimento sobre a árvore da vida, presente nos livros técnicos de ecologia, zoologia, botânica ou qualquer área da biologia. Temos hoje uma biologia bastante unificada pelo discurso evolutivo.

Quando se fala de evolução e seleção natural, as pessoas costumam pensar em animais ou plantas. Você estuda evolução molecular de vírus. O objeto de estudo faz diferença?
Faz diferença porque, no caso dos vírus, a taxa de evolução é muito acelerada e é possível enxergar o processo evolutivo com mais detalhes. Nos grandes mamíferos, é possível enxergar fotografias espalhadas por milhões de anos e fazer inferências sobre o que aconteceu entre uma imagem e outra. No caso dos vírus o espaçamento é menor, mas há algumas complexidades também. O pesquisador precisa estar atento e escolher ferramentas apropriadas para não fazer uma análise enviesada, pois há metodologias para enxergar quadros muito afastados no tempo e outras para quadros muito próximos.

Os vírus usam as células do hospedeiro para se multiplicar e deixam partes de seu material genético inseridos no genoma dos animais. Como os vírus se entrelaçam em nossa história evolutiva?
O que temos até agora são estudos de caso, alguns deles interessantíssimos, mostrando que o papel desses seres é muito mais complexo do que se imaginava. Não há como ponderar se ao longo da história dos mamíferos ou de qualquer outro grupo a contribuição dos vírus tenha sido mais positiva ou mais negativa. Tendemos a achar que é negativa, pois eles são parasitas celulares que utilizam a maquinaria da célula para se replicar e depois a célula morre. Mas nem sempre isso é verdade, e eles podem trazer novidades evolutivas. Isso era inimaginável até algum tempo atrás.

Quanto tempo?
Essas ideias começaram a aparecer por volta dos anos 1990. Depois do entendimento da natureza química do material genético, em 1953, criou-se um conceito de indivíduo muito associado a um único genoma. Entendia-se que, nas células de uma pessoa, o genoma poderia ter pequenas modificações criadas durante o processo de divisão celular. Assim, o genoma de uma célula do fígado poderia ser um pouco diferente do genoma de uma célula do pulmão. Mas ninguém admitiria que outros genomas presentes no organismo, originados de seres tão diferentes quanto bactérias e vírus, poderiam alterar fenótipos e chegar ao ponto de influenciar o comportamento de uma pessoa, como ansiedade e depressão. Chegamos a uma pergunta: afinal de contas, o que é um indivíduo? É apenas o seu genoma ou é o seu genoma e toda essa comunidade de genomas que está presente nesses microrganismos, incluindo os vírus?

Qual será a resposta, na sua avaliação?
O desenvolvimento das técnicas de sequenciamento permite uma análise muito mais detalhada do problema e acho que vamos nos surpreender nos próximos anos. É um desafio considerável inclusive para a bioinformática. A complexidade da informação é gigantesca, porque a variação não é apenas entre pessoas, mas também de uma mesma pessoa ao longo de sua vida. É impossível dar sentido a isso sem o auxílio de computadores. Minha impressão é de que, nos próximos anos, os cursos de biologia terão obrigatoriamente conteúdos de programação de computador para seus estudantes.

O discurso científico é limitado pelo naturalismo metodológico a agentes que devem ter relação mecânica de causa e efeito

Como essa contribuição da microbiologia influencia o conhecimento sobre a teoria da evolução?
O impacto está em andamento. A complexidade do genoma e de sua interação com os genomas de todos esses microrganismos não foi assimilada. Existe uma parcela de pesquisadores que considera a seleção natural a única explicação para a organização surpreendente que vemos nos seres vivos, enquanto outros acham que fenômenos além da seleção natural podem contribuir e defendem que a biologia evolutiva deveria ser reformulada para incorporar essas novidades, abandonando a concepção clássica que vem dos anos 1920. Talvez a seleção natural não seja a única explicação, mas ainda é a melhor que temos para entender a complexidade impressionante dos seres vivos.

Ainda se discute se os vírus são ou não vivos?
A pandemia do coronavírus mostrou que uma molécula de RNA consegue parar o mundo. Dentro das células, essas moléculas levam a uma rede hierárquica de reações em cadeia. Acaba sendo irrelevante perguntar se o vírus é vivo ou não. Esse debate quase virou uma disputa futebolística.

Estamos em um momento no qual se tornou frequente negar a evolução. Como você vive isso na docência?
É um problema real. Com frequência alunos fazem questionamentos de conteúdo religioso, mas raramente é um questionamento filosófico. O que chega em sala de aula é essa interpretação literal, simplista, em que o estudante argumenta: “Ah, não é isso que o capítulo tal do livro tal, do Gênesis, diz”. Acho que isso é bom tema de análise para os sociólogos. Devemos nos perguntar por que isso está aparecendo agora, pois é algo que eu não via 10 anos atrás. É preciso contextualizar o problema. Não se trata de uma disputa entre ciência e religião.

Por que não?
Muitos pesquisadores caem na armadilha e transformam algo que é local e específico em um problema filosófico que não tem solução. Na verdade, estamos lidando com algo muito menos sofisticado. O estudante nunca vem com um discurso teológico avançado. Tenho a impressão de que alguns estudantes entram na aula de evolução achando que é uma disciplina para ensinar ateísmo. Então, é natural que atuem de maneira hostil, porque cresceram em um ambiente familiar religioso e seu entendimento de moral está associado a princípios religiosos.

Como lidar com isso?
Combatendo a percepção de que o discurso científico é pregação ateísta. O professor precisa contextualizar quais são os limites e os agentes do discurso científico. Para o estudante tem que estar claro que o discurso científico é limitado pelo naturalismo metodológico a agentes que devem ter relação mecânica de causa e efeito. Qualquer tipo de agente não natural é incompatível com o universo que caracteriza o discurso científico. Uma vez eu tive de explicar: “Isto aqui é aula de biologia evolutiva, não de apologética ateísta. Eu não sou apologista de matérias do divino, sou biólogo”. Com isso, o aluno fica mais tranquilo e entende que, a partir daqui, fazer qualquer tipo de pulo metafísico é complicado. E isso inclui a aceitação ou rejeição de interpretações metafísicas do naturalismo. Quando alguém diz que hipóteses pseudocientíficas como a do “design inteligente” deveriam entrar nos livros de biologia evolutiva, deve-se indagar o seguinte: o que se propõe está envolto em naturalismo metodológico? Os agentes que estão atuando têm relação mecânica de causa e efeito? Não têm. Então, ótimo, pode-se fazer o que quiser com isso, mas no livro de evolução não entra. Criar essa proteção para o discurso científico evita o problema, mas também tem uma consequência que desagrada a alguns cientistas.

Qual?
A consequência de apresentar o discurso da ciência como apenas um dos discursos possíveis do intelecto humano. Para o cientista, é muito complicado dissociar a relação de igualdade entre ciência e conhecimento. Quando se afirma que existem outras formas de conhecimento fora da proteção do naturalismo metodológico, o cientista tem dificuldade em compreender. Para ele, o mundo só é cognoscível pelo naturalismo metodológico.

Conspiracy theories: how belief is rooted in evolution – not ignorance (The Conversation)

December 13, 2019 9.33am EST – original article

Mikael Klintman PhD, Professor, Lund University

Despite creative efforts to tackle it, belief in conspiracy theories, alternative facts and fake news show no sign of abating. This is clearly a huge problem, as seen when it comes to climate change, vaccines and expertise in general – with anti-scientific attitudes increasingly influencing politics.

So why can’t we stop such views from spreading? My opinion is that we have failed to understand their root causes, often assuming it is down to ignorance. But new research, published in my book, Knowledge Resistance: How We Avoid Insight from Others, shows that the capacity to ignore valid facts has most likely had adaptive value throughout human evolution. Therefore, this capacity is in our genes today. Ultimately, realising this is our best bet to tackle the problem.

So far, public intellectuals have roughly made two core arguments about our post-truth world. The physician Hans Rosling and the psychologist Steven Pinker argue it has come about due to deficits in facts and reasoned thinking – and can therefore be sufficiently tackled with education.

Meanwhile, Nobel Prize winner Richard Thaler and other behavioural economists have shown how the mere provision of more and better facts often lead already polarised groups to become even more polarised in their beliefs.

Tyler Merbler/Flickr, CC BY-SA

The conclusion of Thaler is that humans are deeply irrational, operating with harmful biases. The best way to tackle it is therefore nudging – tricking our irrational brains – for instance by changing measles vaccination from an opt-in to a less burdensome opt-out choice.

Such arguments have often resonated well with frustrated climate scientists, public health experts and agri-scientists (complaining about GMO-opposers). Still, their solutions clearly remain insufficient for dealing with a fact-resisting, polarised society.

Evolutionary pressures

In my comprehensive study, I interviewed numerous eminent academics at the University of Oxford, London School of Economics and King’s College London, about their views. They were experts on social, economic and evolutionary sciences. I analysed their comments in the context of the latest findings on topics raging from the origin of humanity, climate change and vaccination to religion and gender differences.

It became evident that much of knowledge resistance is better understood as a manifestation of social rationality. Essentially, humans are social animals; fitting into a group is what’s most important to us. Often, objective knowledge-seeking can help strengthen group bonding – such as when you prepare a well-researched action plan for your colleagues at work.

But when knowledge and group bonding don’t converge, we often prioritise fitting in over pursuing the most valid knowledge. In one large experiment, it turned out that both liberals and conservatives actively avoided having conversations with people of the other side on issues of drug policy, death penalty and gun ownership. This was the case even when they were offered a chance of winning money if they discussed with the other group. Avoiding the insights from opposing groups helped people dodge having to criticise the view of their own community.

Similarly, if your community strongly opposes what an overwhelming part of science concludes about vaccination or climate change, you often unconsciously prioritise avoiding getting into conflicts about it.

This is further backed up by research showing that the climate deniers who score the highest on scientific literacy tests are more confident than the average in that group that climate change isn’t happening – despite the evidence showing this is the case. And those among the climate concerned who score the highest on the same tests are more confident than the average in that group that climate change is happening.

This logic of prioritising the means that get us accepted and secured in a group we respect is deep. Those among the earliest humans who weren’t prepared to share the beliefs of their community ran the risk of being distrusted and even excluded.

And social exclusion was an enormous increased threat against survival – making them vulnerable to being killed by other groups, animals or by having no one to cooperate with. These early humans therefore had much lower chances of reproducing. It therefore seems fair to conclude that being prepared to resist knowledge and facts is an evolutionary, genetic adaptation of humans to the socially challenging life in hunter-gatherer societies.

Today, we are part of many groups and internet networks, to be sure, and can in some sense “shop around” for new alliances if our old groups don’t like us. Still, humanity today shares the same binary mindset and strong drive to avoid being socially excluded as our ancestors who only knew about a few groups. The groups we are part of also help shape our identity, which can make it hard to change groups. Individuals who change groups and opinions constantly may also be less trusted, even among their new peers.

In my research, I show how this matters when it comes to dealing with fact resistance. Ultimately, we need to take social aspects into account when communicating facts and arguments with various groups. This could be through using role models, new ways of framing problems, new rules and routines in our organisations and new types of scientific narratives that resonate with the intuitions and interests of more groups than our own.

There are no quick fixes, of course. But if climate change were reframed from the liberal/leftist moral perspective of the need for global fairness to conservative perspectives of respect for the authority of the father land, the sacredness of God’s creation and the individual’s right not to have their life project jeopardised by climate change, this might resonate better with conservatives.

If we take social factors into account, this would help us create new and more powerful ways to fight belief in conspiracy theories and fake news. I hope my approach will stimulate joint efforts of moving beyond disputes disguised as controversies over facts and into conversations about what often matters more deeply to us as social beings.

Steven Pinker talks Donald Trump, the media, and how the world is better off today than ever before (ABC Australia)

Updated

“By many measures of human flourishing the state of humanity has been improving,” renowned cognitive scientist Steven Pinker says, a view often in contrast to the highlights of the 24-hour news cycle and the recent “counter-enlightenment” movement of Donald Trump.

“Fewer of us are dying of disease, fewer of us are dying of hunger, more of us are living in democracies, were more affluent, better educated … these are trends that you can’t easily appreciate from the news because they never happen all at once,” he says.

Canadian-American thinker Steven Pinker is the author of Bill Gates’s new favourite book — Enlightenment Now — in which he maintains that historically speaking the world is significantly better than ever before.

But he says the media’s narrow focus on negative anomalies can result in “systematically distorted” views of the world.

Speaking to the ABC’s The World program, Mr Pinker gave his views on Donald Trump, distorted perceptions and the simple arithmetic that proves the world is better than ever before.

Donald Trump’s ‘counter-enlightenment’

“Trumpism is of course part of a larger phenomenon of authoritarian populism. This is a backlash against the values responsible for the progress that we’ve enjoyed. It’s a kind of counter-enlightenment ideology that Trumpism promotes. Namely, instead of universal human wellbeing, it focusses on the glory of the nation, it assumes that nations are in zero-sum competition against each other as opposed to cooperating globally. It ignores the institutions of democracy which were specifically implemented to avoid a charismatic authoritarian leader from wielding power, but subjects him or her to the restraints of a governed system with checks and balances, which Donald Trump seems to think is rather a nuisance to his own ability to voice the greatness of the people directly. So in many ways all of the enlightenment forces we have enjoyed, are being pushed back by Trump. But this is a tension that has been in play for a couple of hundred years. No sooner did the enlightenment happen that a counter-enlightenment grew up to oppose it, and every once in a while it does make reappearances.”

News media can ‘systematically distort’ perceptions

“If your impression of the world is driven by journalism, then as long as various evils haven’t gone to zero there’ll always be enough of them to fill the news. And if journalism isn’t accompanied by a bit of historical context, that is not just what’s bad now but how bad it was in the past, and statistical context, namely how many wars? How many terrorist attacks? What is the rate of homicide? Then our intuitions, since they’re driven by images and narratives and anecdotes, can be systematically distorted by the news unless it’s presented in historical and statistical context.

‘Simple arithmetic’: The world is getting better

“It’s just a simple matter of arithmetic. You can’t look at how much there is right now and say that it is increasing or decreasing until you compare it with how much took place in the past. When you look at how much took place in the past you realise how much worse things were in the 50s, 60s, 70s and 80s. We don’t appreciate it now when we concentrate on the remaining horrors, but there were horrific wars such as the Iran-Iraq war, the Soviets in Afghanistan, the war in Vietnam, the partition of India, the Bangladesh war of independence, the Korean War, which killed far more people than even the brutal wars of today. And if we only focus on the present, we ought to be aware of the suffering that continues to exist, but we can’t take that as evidence that things have gotten worse unless we remember what happened in the past.”

Don’t equate inequality with poverty

“Globally, inequality is decreasing. That is, if you don’t look within a wealthy country like Britain or the United States, but look across the globe either comparing countries or comparing people worldwide. As best as we can tell, inequality is decreasing because so many poor countries are getting richer faster than rich countries are getting richer. Now within the wealthy countries of the anglosphere, inequality is increasing. And although inequality brings with it a number of serious problems such as disproportionate political power to the wealthy. But inequality itself is not a problem. What we have to focus on is the wellbeing of those at the bottom end of the scale, the poor and the lower middle class. And those have not actually been decreasing once you take into account government transfers and benefits. Now this is a reason we shouldn’t take for granted, the important role of government transfers and benefits. It’s one of the reasons why the non-English speaking wealthy democracies tend to have greater equality than the English speaking ones. But we shouldn’t confuse inequality with poverty.”

Language is learned in brain circuits that predate humans (Georgetown University)

PUBLIC RELEASE: 

GEORGETOWN UNIVERSITY MEDICAL CENTER

WASHINGTON — It has often been claimed that humans learn language using brain components that are specifically dedicated to this purpose. Now, new evidence strongly suggests that language is in fact learned in brain systems that are also used for many other purposes and even pre-existed humans, say researchers in PNAS (Early Edition online Jan. 29).

The research combines results from multiple studies involving a total of 665 participants. It shows that children learn their native language and adults learn foreign languages in evolutionarily ancient brain circuits that also are used for tasks as diverse as remembering a shopping list and learning to drive.

“Our conclusion that language is learned in such ancient general-purpose systems contrasts with the long-standing theory that language depends on innately-specified language modules found only in humans,” says the study’s senior investigator, Michael T. Ullman, PhD, professor of neuroscience at Georgetown University School of Medicine.

“These brain systems are also found in animals – for example, rats use them when they learn to navigate a maze,” says co-author Phillip Hamrick, PhD, of Kent State University. “Whatever changes these systems might have undergone to support language, the fact that they play an important role in this critical human ability is quite remarkable.”

The study has important implications not only for understanding the biology and evolution of language and how it is learned, but also for how language learning can be improved, both for people learning a foreign language and for those with language disorders such as autism, dyslexia, or aphasia (language problems caused by brain damage such as stroke).

The research statistically synthesized findings from 16 studies that examined language learning in two well-studied brain systems: declarative and procedural memory.

The results showed that how good we are at remembering the words of a language correlates with how good we are at learning in declarative memory, which we use to memorize shopping lists or to remember the bus driver’s face or what we ate for dinner last night.

Grammar abilities, which allow us to combine words into sentences according to the rules of a language, showed a different pattern. The grammar abilities of children acquiring their native language correlated most strongly with learning in procedural memory, which we use to learn tasks such as driving, riding a bicycle, or playing a musical instrument. In adults learning a foreign language, however, grammar correlated with declarative memory at earlier stages of language learning, but with procedural memory at later stages.

The correlations were large, and were found consistently across languages (e.g., English, French, Finnish, and Japanese) and tasks (e.g., reading, listening, and speaking tasks), suggesting that the links between language and the brain systems are robust and reliable.

The findings have broad research, educational, and clinical implications, says co-author Jarrad Lum, PhD, of Deakin University in Australia.

“Researchers still know very little about the genetic and biological bases of language learning, and the new findings may lead to advances in these areas,” says Ullman. “We know much more about the genetics and biology of the brain systems than about these same aspects of language learning. Since our results suggest that language learning depends on the brain systems, the genetics, biology, and learning mechanisms of these systems may very well also hold for language.”

For example, though researchers know little about which genes underlie language, numerous genes playing particular roles in the two brain systems have been identified. The findings from this new study suggest that these genes may also play similar roles in language. Along the same lines, the evolution of these brain systems, and how they came to underlie language, should shed light on the evolution of language.

Additionally, the findings may lead to approaches that could improve foreign language learning and language problems in disorders, Ullman says.

For example, various pharmacological agents (e.g., the drug memantine) and behavioral strategies (e.g., spacing out the presentation of information) have been shown to enhance learning or retention of information in the brain systems, he says. These approaches may thus also be used to facilitate language learning, including in disorders such as aphasia, dyslexia, and autism.

“We hope and believe that this study will lead to exciting advances in our understanding of language, and in how both second language learning and language problems can be improved,” Ullman concludes.

Human societies evolve along similar paths (University of Exeter)

PUBLIC RELEASE: 

Societies ranging from ancient Rome and the Inca empire to modern Britain and China have evolved along similar paths, a huge new study shows.

Despite their many differences, societies tend to become more complex in “highly predictable” ways, researchers said.

These processes of development – often happening in societies with no knowledge of each other – include the emergence of writing systems and “specialised” government workers such as soldiers, judges and bureaucrats.The international research team, including researchers from the University of Exeter, created a new database of historical and archaeological information using data on 414 societies spanning the last 10,000 years. The database is larger and more systematic than anything that has gone before it.

“Societies evolve along a bumpy path – sometimes breaking apart – but the trend is towards larger, more complex arrangements,” said corresponding author Dr Thomas Currie, of the Human Behaviour and Cultural Evolution Group at the University of Exeter’s Penryn Campus in Cornwall.

“Researchers have long debated whether social complexity can be meaningfully compared across different parts of the world. Our research suggests that, despite surface differences, there are fundamental similarities in the way societies evolve.

“Although societies in places as distant as Mississippi and China evolved independently and followed their own trajectories, the structure of social organisation is broadly shared across all continents and historical eras.”

The measures of complexity examined by the researchers were divided into nine categories. These included:

  • Population size and territory
  • Number of control/decision levels in administrative, religious and military hierarchies
  • Information systems such as writing and record keeping
  • Literature on specialised topics such as history, philosophy and fiction
  • Economic development

The researchers found that these different features showed strong statistical relationships, meaning that variation in societies across space and time could be captured by a single measure of social complexity.

This measure can be thought of as “a composite measure of the various roles, institutions, and technologies that enable the coordination of large numbers of people to act in a politically unified manner”.

Dr Currie said learning lessons from human history could have practical uses.

“Understanding the ways in which societies evolve over time and in particular how humans are able to create large, cohesive groups is important when we think about state building and development,” he said.

“This study shows how the sciences and humanities, which have not always seen eye-to-eye, can actually work together effectively to uncover general rules that have shaped human history.”

###

The new database of historical and archaeological information is known as “Seshat: Global History Databank” and its construction was led by researchers from the University of Exeter, the University of Connecticut, the University of Oxford, Trinity College Dublin and the Evolution Institute. More than 70 expert historians and archaeologists have helped in the data collection process.

The paper, published in Proceedings of the National Academy of Sciences, is entitled: “Quantitative historical analysis uncovers a single dimension of complexity that structures global variation in human social organisation.”

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…

Click here for more information.

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…

Click here for more information.

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