Vulnerability made us human: how our early ancestors turned disability into advantage

Jun 17, 2015

by David Garner

A new evolutionary theory explains how critically small populations of early humans survived, despite an increased chance of hereditary disabilities being passed to offspring.

Anthropologists at the University of York and Newcastle University have studied how our  coped during periods when the population dwindled, and have developed a model of early hominins as ‘Vulnerable Apes’.

Small numbers of individuals in the distant past would sometimes be driven to landscapes that allowed them to avoid predators and competitors, or exploit emergency resources. They would have become isolated, creating genetic ‘bottlenecks’ which brought disabling genes to the surface.

The researchers argue that these groups would have experienced a new type of selection pressure – not selection in favour of individuals with the ‘best’ genes but selection that favoured those who were able to cope with the challenges that their genes threw at them.

They speculate that our need to socialise and ability to experiment and learn new behaviours, as well as our compassion and communication skills, arose as coping strategies that allowed our ancestors to get through these bottlenecks. In so doing, they turned ‘disabilities’ such as weak jaws, hairless bodies, short, weak arms and straight feet that can’t climb trees, into opportunities that formed the platform for future .


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21 comments on “Vulnerability made us human: how our early ancestors turned disability into advantage

  • 1
    aroundtown says:

    A new evolutionary theory explains how critically small populations of early humans survived, despite an increased chance of hereditary disabilities being passed to offspring.

    I’m still fairly pissed-off at the gene’s I inherited from my parents but I’ve learned to work with them. Nothing like inheriting a propensity for depression to throw a rock in the wheel of potential progress. If genes where Jeans I didn’t get nice tailored dress slacks, I got tattered work weave trousers. I think we all struggle with limitations that are not of our making but it doesn’t hurt to be aware that they’re in play. Bye the way, to those who got the nice slacks I don’t hold a grudge, I’m more than willing to utilize your gifts. At the end of the day were all in the homo sapiens club so you do what you can do within the group.



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  • @OP – In so doing, they turned ‘disabilities’ such as weak jaws, hairless bodies, short, weak arms and straight feet that can’t climb trees, into opportunities that formed the platform for future human evolution.

    I’m not sure about this.
    Rather than “disabilities” weak arms and straight feet, sound more like adaptations to open plains where upper body strength for swinging in trees is no longer needed.. There is also a reduction in climbing ability with increased body size – as with lions compared to leopards.

    Relative limb strengths in modern primates are shown in this discussion.

    https://www.richarddawkins.net/2015/06/comparison-of-bonobo-anatomy-to-humans-offers-evolutionary-clues/



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  • Also, there’s not much point in retaining tree-climing adaptations, when the forests have all fallen down as a result of desertification in a climate which is drying out. You need to adapt to living on a savannah, outsmarting lions and cataching nice juicy cattle and antelope.



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  • 5
    aroundtown says:

    I don’t expect the study to change the status quo though. Nothing is quite as permanent as man’s intrenched ignorance when it comes to the big issues. They will kick the can down the road no matter how large it is.



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  • 6
    aroundtown says:

    I do have a follow on riddle for the very bright individuals here on RDFRS, and hopefully they will entertain my question. I feel it’s an important one. I am not trying to goad anyone. Okay, here goes.

    How is it we can get into a lather over one man on the Tim Hunt thread, (not saying it’s not an important subject/situation), with great concern and response (228 and growing), but the condition of all men and women who are in danger of getting the grandest forced ejection ever meted out might garner a thread count of maybe 20 some-odd responses, here or anywhere else?

    I am simply at a loss to explain it. Oceans have tsunami sensors to warn of impending dangers, loud sirens to warn of tornado’s, air raids, or any other calamity on land, yet a story that should be front page news in my opinion regarding our possible extinction will likely be swept to the back burner and receive marginal consideration, that’s my guess. Why do we avoid the big ones, fear? I’m beginning to wonder if it will it change, or gain a dimension similar to a movie I watched recently called “The Core” where a computer hacker is enlisted to ensure everyone is kept in the dark.

    Something seems amiss and out of alignment as concerns the ranking of severity and subsequent discussions really, but the fantasy proposition that a hacker would be needed seems comical to me at this point since the internal hack within us seems to have all the bases covered to ignore the big ones.

    If there something I’m missing? I sure would appreciate even a guess so I can check my barometer on this Stanford study and where it’s likely to go.



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  • If there something I’m missing?

    I share your concerns and endorse your comments. When I raise things like population, or the lunacy of free market capitalism that requires compound growth, forever, in a closed system, I can see the people glaze over. I suspect evolution has given us the ability to think a week ahead, and remember the week past, but while we can turn our minds to greater time periods, forward and back, our brains can’t act. We can’t think about the next thing we are doing, and consider the consequences of that action and the impact on another person in 100 years time. It is a fatal flaw in our make up. We may knowingly go extinct, which would make us the most stupid species that every lived.

    So Aroundtown, I share your inability to explain the thread comparison, or the greater consequences of your observation.

    This has just been published on Standford News. The earth is now going through the greatest mass extinction event since the dinosaurs. The graph is instructive. Middle left.

    http://news.stanford.edu/news/2015/june/mass-extinction-ehrlich-061915.html

    Again referring back to our species inability to comprehend the import of a study like this, we can’t survive without the other species on this planet. We think we can, but the entire environment is inter meshed. No bees. No pollination. No food. No plankton. No fish. No food. No forests. No transpiration. No rain. No food. Etc.

    I think Bertrand Russell nailed it when he said, “Most people would rather die than think. And most people do.”



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  • 8
    aroundtown says:

    David, you gave me a very clear answer and I am impressed as usual. I appreciate your thoughts and opinion and I feel your spot on with no waffling around the edges to appease or please on this subject. Sincere thanks are in order, really.



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  • Aroundtown. The reason we don’t see a problem, or recognise these problems, is because we have a very unhealthy combination in attitude and understanding of ignorance, then fear and then apathy and then when enlightenment happens a feeling of hopelessness. (I think).



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  • 10
    aroundtown says:

    Thanks Liam,

    For me it’s exasperating that action on something like this is mulled over and then deposited into the circle bin, discarded because it wasn’t enough of a fashion moment for the collective troop of man. It boggles the mind.

    It’s weird how things can stick with you over the years, and one that comes up fairly often for me, regardless of whether I want it too or not, is a suggestion from my brother whose passed away now, he used to express it with great regularity and sometimes I want to shout it out, but the crudeness would only irritate I’m afraid. It’s this and maybe someone will get use out of it, or maybe a laugh, here goes – Take two steps back and pull your head out of your ass, maybe then you will be able to see and hear what is going on around you!!!!!

    No pussyfooting from him, always went for the jugular when he wanted to get his point across. I will admit it was a strange family, and often times I thought they could beat out the Munsters or Adam family for first place in the odd family category. We can’t pick our parents or siblings and often times we get quite a thrill ride that is unavoidable, both good and bad.

    But I will say this, regardless of their crudeness I did get some useful tidbit from them. Not to happy about their education priorities, I think they thought it happened through inattentive osmosis, and I am certainly not appreciative of the yoke of religion they placed around my neck, but with some difficulty I was able to scrap that off myself, but some of it was useful for survival in the main, and the push for you to stand up to oppression. My mother would say – If I’m being raped, I’m sure as hell going to say something and fight back!!!! There you go, another gem from the family tree : )



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  • Re: link

    Apologies, I did not see this before posting it myself on “Placenta’ article. Nice to be reminded more than a few share the same concerns.

    mulled over

    Few days back, on the u.s. Capitol grounds, bee-keepers were called in to corral bees ‘gone wild’ (just searching for a new home). Cute, informative article, but the last para was discouraging. Lawmakers are “considering” whether certain pesticides are (partially) to blame for CCD. Argh.



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  • 12
    aroundtown says:

    Liam,

    I re-read my response to you Liam and I find myself having to backtrack as I often do. It dawned on my that you may have concluded that I was addressing my brothers opinion towards you. Not at all my friend, and wanted to be perfectly clear there. I am thankful for your opinion, and much appreciative of it. I am a misfit in many instances and I would be the first to admit it. I seem to have a penchant for error unfortunately, so please forgive me if you were offended by an inference that you may have thought of as directed towards you. Man that brother of mine is still getting me into trouble : )



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  • 13
    aroundtown says:

    I know Bonnie, just crazy. We had an episode in Oregon I believe where thousands of bee’s dropped dead, and just the previous day it was discovered that pesticide had been sprayed on the bushes in the bee’s vicinity. Could not get them to admit the connection though, the pesticide lobby is a piece of work, just like the other lobbyists at large who bury their heads in the sand and overlook everything that is affected by their pandering.

    I will add this – it’s looking more and more like were the grass and nature is getting ready to give us a severe clipping, or maybe removal for a fresh new landscape?



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  • 14
    aroundtown says:

    I would add this too, since it seems a good time to mention it. I vote Democratic usually but that doesn’t give me what I would like to see out of Democratic leaders generally. I would love to see a woman president but the frontrunner of that distinction here in good ole USA is Hillary Clinton, and some would likely be unaware that she is indeed – a lobbyists best friend in every sense of the word. That scares the hell out of me.

    I’m tending to side with George Carlin on his assertions in this regard as of late – doesn’t matter who you vote for, your going to be disappointed.



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  • In Australia, we have the luxury of a Green Party, which for the most, is rational and evidenced based. In the US, you have the choice of the right wing Democrats (Judge on a world wide comparison) and the extreme right wing Republicans, which in the rest of the free western world, would be a fringe extremist party.



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  • 16
    aroundtown says:

    Well here’s another one with pretty much the same tone. What I find odd is a lot of these opinions will retain a fraction of injected optimism with statements like “if we act soon enough we will mitigate these dangers” but have you noticed as the years go by, do a dare say decades, you end up seeing little or no effort towards the goal.

    I’m sure I am not alone in this regard. I have a daughter and two grandchildren so this is becoming quite agitating that we are receiving little more than lip service on our plight. Let’s think of the children shall we.

    http://blogs.reuters.com/great-debate/2015/06/18/a-child-born-today-may-live-to-see-humanitys-end-unless/



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  • The researchers argue that these groups would have experienced a new type of selection pressure – not selection in favour of individuals with the ‘best’ genes but selection that favoured those who were able to cope with the challenges that their genes threw at them.

    I don’t see the distinction being made here. It sounds like they are saying not “the best” in terms of running or fighting but rather best as in best adapted to their environment which is already the definition I would think an evolutionary biologist would use anyway.



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  • I looked at the full article and still don’t get it. It sounds to me like either the result is trivial (its just pointing out that “fittest” for humans was complex and not just based on things like strength and speed) or is an attempt to bring in group selection again without addressing the fundamental problem with group selection that has been demonstrated by Dawkins and others. But I didn’t understand the point about the tree vs. network, I mean I know the difference between a tree and a network and understand why descent is commonly thought to be a tree but the alternative that they were proposing, the network I didn’t get why its a network and why that has relevance to the point about fitness.



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  • From the actual paper’s abstract:

    The evolutionary approach to archaeological systems has therefore been hampered by the ‘modern synthesis’ – a gene-centred model of evolution as a process that eliminates those that cannot handle stress. The result has been a form of environmental determinism that explains human evolution in terms of heroic struggles and selective winnowing

    I guess I missed the chapter in The Selfish Gene that talked about how the whole point of evolution was a “heroic struggle” to “winnow out” those that can’t handle stress. It amazes me when I see people trying to make serious discussions about evolution talking in such value laden terms. Curious if anyone has a different reaction.



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  • One final thought. I was thinking over the “tree vs. network” point and it seems to me the distinction they are making is also rather facile. As I thought about why we usually represent lines of descent for all the species as a tree its really just an abstraction and a way for our human brains to represent something that is in reality far more complex. I.e., if we were to graph out all the connections it would of course be a network and not a tree (I’m speaking in graph theoretic terms of course) so again their major “finding” isn’t something that requires a computer model but rather something you could already have said just by being a bit more rigorous in your thinking. That is what all of this seems like to me frankly, is that (at best) they are really saying that a lot of their anthropology colleagues use terms from evolution incorrectly (e.g., talking about “heroic struggles”) so its kind of an easy win to just correct them but not something I would consider serious research.



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  • Red Dog
    Jun 23, 2015 at 10:06 am

    One final thought. I was thinking over the “tree vs. network” point and it seems to me the distinction they are making is also rather facile. As I thought about why we usually represent lines of descent for all the species as a tree its really just an abstraction and a way for our human brains to represent something that is in reality far more complex. I.e., if we were to graph out all the connections it would of course be a network and not a tree

    The charts do usually present the conventional notion of a tree.

    However, not all trees are like that, and some do have multitudes of interconnected trunks, branches and roots!

    https://en.wikipedia.org/?title=Banyan#Classification
    The original banyan, the species F. benghalensis, can grow into a giant tree covering several hectares.

    Older banyan trees are characterized by their aerial prop roots that grow into thick woody trunks which, with age, can become indistinguishable from the main trunk. Old trees can spread out laterally, using these prop roots to cover a wide area. In some species the effect is for the props to develop into a sort of forest covering a considerable area, every trunk connected directly or indirectly to the central trunk.



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