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Thread: Aquatic ape

  1. #1 Aquatic ape 
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    I read about this theory in the 80's: Humans survived some drought periods living around shorelines, wading and even swimming in water, where there was food. This is supposed to account for changes in posture, hairlessness, tool use (chipping oysters), body fat, even boobs.

    Where'd it go? Opinions?


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    WYSIWYG Moderator marnixR's Avatar
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    this topic has been discussed on this forum about a year ago :

    Aquatic Ape Theory

    it would appear that, although at first glance an elegant alternative explanation, it has been refuted, even if the same old arguments resurface from time to time


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    I don't want to necropost in that, but thanks. Did read it.

    Looks to me like both sides were uncompromising, where they could have synthesized. It's not like an either/or proposition. Is it?

    For example:

    I can sweat profusely in hot weather. Does this suggest all my ancestors came from always hot climates? No.

    Circulation in my extremities shuts down in extreme cold, to conserve critical heat. Does this suggest all my ancestors came from always cold climates? No.

    I'm an assembly of adaptations. Maybe some of my ancestors adapted somewhat to an environmental challenge, even one visited occasionally. So I'm fairly comfortable and mobile in a tree. That doesn't mean my ancestors climbed trees more often than they absolutely had to! An occasional test is enough. Consider the hand. It's multi-purpose. We do different things with it. So with the entire body. Why claim the body, widely adapted to meet a range of challenges, didn't also adapt to water?

    I think I have a bias to aquatic ape theory because of all the time I spend on shorelines with my son, prying delicacies off the rocks, corralling fish into tide pools, etc. We love it. There's just so much food in the intertidal zone only smart scavengers can get. I see those clever raccoons doing same, and think this a perfect environment to develop ingenuity and tools (which we do, spontaneously). Yes we wade down to grab tempting things. Unfortunately Western Canada's waters are a bit cold for prolonged exposure, and I won't be caught swimming in them!
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    WYSIWYG Moderator marnixR's Avatar
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    my main problem with the aquatic ape theory is that most of it depends on soft anatomy, and as such it's very hard to determine WHEN certain of our adaptations happened
    if you don't know when something happened, not even to the nearest million years, then it becomes very hard to relate changes to outside factors causing these changes

    however, i WOULD be interested in finding out whether there's any remains in the Danakil alps that might throw some light on the issue
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    I don't know that fossils or even technologies out of one region would look any different than another, if the populations were still mixing.

    See what I'm saying? You can have adaptation throughout a population, when only one end is... dipped, shall we say... into novel conditions. If the changed nose shape costs a savanna dweller nothing, what's stopping that from spreading through the whole population?

    AAT failed because we thought shoreline and savanna populations must be exclusive.

    Consider the common North American raccoon. In my neck of the woods, coast Natives call her "washing hands". The name describes the typical activity of feeling around underwater, upturning rocks, their chins held high as they wade along the coastline... raccoons are very effective tidal zone scavengers, with their nimble, sensitive paws. So we have family groups that basically live off the sea. Raccoons also live inland. They always have. Same species! Would we say a raccoon born on the prairie is partially adapted to the water? Why not?
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    the reason why i picked out the Danakil alps is that this is one of the few predictions made in one of Elaine Morgan's books that can be checked out - if fossils of the right age turn up in the right spot then at least there would be some concrete evidence that matches the predicted time and space and could lead to further investigations

    although, your raccoon story shows that behavioural adaptations can initially happen without noticeable differences of the skeleton, so not sure whether finding fossils there really would give us the necessary clues
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    It seems to me unlikely we would find specialization. Why Morgan had to claim we only lived off water bodies, rivers, etc. in this particular isolated place and time... beyond me. Kinda set a trap for the theory.

    She actually claims an "intervening stage" "from trees to land". As if we can't thrive and adapt in many conditions simultaneously, throughout our varied range.

    On the other hand, savanna proponents likely feel "you're in the trees or you're not, ever".
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    if the case of Ardipithecus has taught us anything, it's that bipedalism had already developed in a forest environment
    + A.afarensis still has skeletal clues that it was comfortable both on the ground and in the trees

    imo bipedalism just opened up options when the forest environment retreated, unlike our chimp relatives who were forced to stay in the forests
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    Quote Originally Posted by Pong
    On the other hand, savanna proponents likely feel "you're in the trees or you're not, ever".
    Savanna theory is dead. Mosaic theory replaced it. Morgan suggested periodic flooding (which is proven) of tree habitat would foster the move to a semi-aquatic existence.

    Marnix's point about the difficulty with soft tissue issues may be resolved through detailed gene analysis. (I think. )
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    Quote Originally Posted by Pong
    Consider the common North American raccoon. In my neck of the woods, coast Natives call her "washing hands". The name describes the typical activity of feeling around underwater, upturning rocks, their chins held high as they wade along the coastline... raccoons are very effective tidal zone scavengers, with their nimble, sensitive paws. So we have family groups that basically live off the sea. Raccoons also live inland. They always have. Same species! Would we say a raccoon born on the prairie is partially adapted to the water? Why not?
    A little off topic, but the raccoon is not adapted to marine water. I think the washing hand thing comes from their dousing behavior, which they do inland in fresh water also. These are forest adapted animals that have gripping front paws for climbing trees, these front paws also made them highly adaptable to a lot of habitats because they could then manipulate a lot of objects other animals can't. So they can turn over rocks and catch fish, after they became adapted to catching fresh water fish it isn't much of a stretch to go after shellfish in tidal regions.

    They're also annoyingly good at opening trash cans >.>
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    Quote Originally Posted by i_feel_tiredsleepy
    These are forest adapted animals that have gripping front paws for climbing trees
    I can't see why the adaptation must have one cause though, as if the animal only climbed trees. Did it constantly grip tree limbs, never employing those same paws for other tasks?

    Consider cat claws. One argues the claws were developed for scaling sheer surfaces (this also allows cats to pin prey). Another argues the claws were developed for pinning prey (this also allows cats to scale trees). Who's wrong?

    Consider a chimpanzee's hands. What are they for, specifically? :wink:

    Can bipedalism admit multiple, simultaneous advantages?

    If so, then it's no stretch to imagine one sister using her improved bipedalism to gather bundles in a forest; while at exactly the same time a second sister uses it to scan a horizon; while even farther down the valley our third sister forages the river, bipedally.
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    Quote Originally Posted by Pong
    Quote Originally Posted by i_feel_tiredsleepy
    These are forest adapted animals that have gripping front paws for climbing trees
    I can't see why the adaptation must have one cause though, as if the animal only climbed trees. Did it constantly grip tree limbs, never employing those same paws for other tasks?

    Consider cat claws. One argues the claws were developed for scaling sheer surfaces (this also allows cats to pin prey). Another argues the claws were developed for pinning prey (this also allows cats to scale trees). Who's wrong?

    Consider a chimpanzee's hands. What are they for, specifically? :wink:

    Can bipedalism admit multiple, simultaneous advantages?

    If so, then it's no stretch to imagine one sister using her improved bipedalism to gather bundles in a forest; while at exactly the same time a second sister uses it to scan a horizon; while even farther down the valley our third sister forages the river, bipedally.
    The ability to climb trees is the feature that would be selected for most though since it would dramatically increase survival. It indeed does help them in gathering food, and which came first isn't really important, but raccoons are by and far descidious forest dwellers, and the adaptation to climb trees is very common with descidious mammals.
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  14. #13  
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    Quote Originally Posted by i_feel_tiredsleepy
    the adaptation to climb trees is very common with descidious mammals.
    Yeah, I yet appreciate it when I have some pruning to do... cherry trees too.

    But I want to go back to an earlier question. If we have a population, occupying ranges A & B, each range adequate, yet range B offers some sweet exploit... exploit like, break the nut, you win a prize... how does the population adapt to that? Suppose that gaining a bit more dexterity (to break the nut) is highly advantageous to B-dwellers, and costs A-dwellers nothing. A takes it on, no?

    I'm looking for examples. :? Sure with modern humans we have lots of traits associated with a particular region, which we may not live in. The traits cost nothing, so they spread (e.g. brown eyes). Better "real world" examples?

    Best I can think of is the dungeness crab, named for Dungeness Spit, a sandbar where it's obscenely abundant. This crab is well adapted to a muddy bottom (e.g. at Dungeness), which it buries into when threatened. The funny thing is, the species ranges from Aleutian Islands to California - much of its habitat offers no sandy or muddy bottom at all. Apparently, the skeletal characteristics that help dungeness bury (if possible) don't cost the general population much. So they all share the adaptation, even where irrelevant.
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    WYSIWYG Moderator marnixR's Avatar
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    Quote Originally Posted by Pong
    But I want to go back to an earlier question. If we have a population, occupying ranges A & B, each range adequate, yet range B offers some sweet exploit... exploit like, break the nut, you win a prize... how does the population adapt to that? Suppose that gaining a bit more dexterity (to break the nut) is highly advantageous to B-dwellers, and costs A-dwellers nothing. A takes it on, no?
    survival of a species does usually not just depend on one trick (although if it's one that means the difference between life and death, then it might do) : it's not just a matter of finding sufficient food, but what is the reproduction pattern, how heavy is the predation, how prone is the environment to fluctuations etc.

    also, do i see a hint of lamarckism in your reasoning (it's good to be able to crack a nut, so the first one to develop the dexterity to do so will flourish) ?
    in my experience i see that species develop a certain trait through random variation, which then gets co-opted into other usages, and depending on the needs of the organism in its environment can become a useful adaptation

    SJ Gould used the word exaptation for this type of co-opting of existing traits, and i think it's a far more important phenomenon than i usually see it being given credit for
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    Wanna take a crack at the question?

    If it costs nothing, to any member of a species occupying both environments A & B, will those occupying A take adaptations out of B?

    For hypothetical example. Some mountain goats. A western population, an eastern population, same species, they do mix though an individual wouldn't possibly travel the whole range. The westerners suffer no predation and are limited only by scarcity of food. The easterners are harassed by cougars which prey mainly on deer of the adjacent forest. These eastern goats would do well to camouflage with a reddish shrub particular to their range. Colouration makes little difference to the western goats. Do the western goats turn rusty too?
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    WYSIWYG Moderator marnixR's Avatar
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    if the gene flow between the 2 populations is restricted then the answer is probably no

    although, as you admitted yourself, this is hypothetical - very few instances of adaptation are free of cost
    who knows, maybe the reddish coat requires higher intakes of a certain trace element in their diet
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    Quote Originally Posted by Pong
    For hypothetical example. Some mountain goats. A western population, an eastern population, same species, they do mix though an individual wouldn't possibly travel the whole range. The westerners suffer no predation and are limited only by scarcity of food. The easterners are harassed by cougars which prey mainly on deer of the adjacent forest. These eastern goats would do well to camouflage with a reddish shrub particular to their range. Colouration makes little difference to the western goats. Do the western goats turn rusty too?
    No.
    Since there is some interbreeding between populations there would be an increase in rusty coats in the west, that would drop of with distance from the areas where the rust was an advantage.
    The question could be answered more fully if you specified how many genes determined the colour change and the dominant/recessive character of the alleles involved.
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    Quote Originally Posted by i_feel_tiredsleepy
    Quote Originally Posted by Pong
    Quote Originally Posted by i_feel_tiredsleepy
    These are forest adapted animals that have gripping front paws for climbing trees
    I can't see why the adaptation must have one cause though, as if the animal only climbed trees. Did it constantly grip tree limbs, never employing those same paws for other tasks?

    Consider cat claws. One argues the claws were developed for scaling sheer surfaces (this also allows cats to pin prey). Another argues the claws were developed for pinning prey (this also allows cats to scale trees). Who's wrong?

    Consider a chimpanzee's hands. What are they for, specifically? :wink:

    Can bipedalism admit multiple, simultaneous advantages?

    If so, then it's no stretch to imagine one sister using her improved bipedalism to gather bundles in a forest; while at exactly the same time a second sister uses it to scan a horizon; while even farther down the valley our third sister forages the river, bipedally.
    The ability to climb trees is the feature that would be selected for most though since it would dramatically increase survival. It indeed does help them in gathering food, and which came first isn't really important, but raccoons are by and far descidious forest dwellers, and the adaptation to climb trees is very common with descidious mammals.
    The raccoon's hands are a very clear adaptation to a aquatic environment. They are highly developed sensor organs that have special adaptations that make it possible for them to work properly in water. One of which is that cold water doesn't affect the effiency of the touch sense. Which is does for instance in our hands.
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    Quote Originally Posted by spuriousmonkey
    The raccoon's hands are a very clear adaptation to a aquatic environment. They are highly developed sensor organs that have special adaptations that make it possible for them to work properly in water. One of which is that cold water doesn't affect the effiency of the touch sense. Which is does for instance in our hands.
    Those adaptations came after the development of hands though, which is evident by the fact that other members of the raccoon family that are not aquatic adapted at all still have gripping hands, such as the lesser panda and kinkajou. Anyway his statement was that the hands had evolved for marine water.

    The raccoon is primarily a descidious forest dwelling omnivore that is adapted to scrounging for small animals in many environments.
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    Quote Originally Posted by i_feel_tiredsleepy
    Anyway his statement was that the hands had evolved for marine water.
    Not quite. I said:
    Quote Originally Posted by Pong
    Would we say a raccoon born on the prairie is partially adapted to the water? Why not?
    Quote Originally Posted by Pong
    I can't see why the adaptation must have one cause though, as if the animal only climbed trees.
    My main point being that AAT was doomed as proposed, because Morgan insisted on the same compartmentalization her opponents stuck to... and we see today (see above).
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    Quote Originally Posted by i_feel_tiredsleepy
    Quote Originally Posted by spuriousmonkey
    The raccoon's hands are a very clear adaptation to a aquatic environment. They are highly developed sensor organs that have special adaptations that make it possible for them to work properly in water. One of which is that cold water doesn't affect the effiency of the touch sense. Which is does for instance in our hands.
    Those adaptations came after the development of hands though, which is evident by the fact that other members of the raccoon family that are not aquatic adapted at all still have gripping hands, such as the lesser panda and kinkajou. Anyway his statement was that the hands had evolved for marine water.

    The raccoon is primarily a descidious forest dwelling omnivore that is adapted to scrounging for small animals in many environments.
    pfft..

    why stop there.

    The tetrapod limb is a direct modification of a swimming organ. The fin.
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    Quote Originally Posted by spuriousmonkey
    pfft..

    why stop there.

    The tetrapod limb is a direct modification of a swimming organ. The fin.
    Except if you ask the question "why does the raccoon have gripping hands" it would be for climbing trees, the adaptations to foraging come after.
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  24. #23  
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    Hands suitable for gripping aren't the adaptation of the raccoon. Hands as a tactile organ are.
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  25. #24  
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    Quote Originally Posted by i_feel_tiredsleepy
    adaptations to foraging come after.
    It seems you believe being able to handle objects must owe to arboreal mastery first. Climbing trees is that crucial.

    Now I'm not saying the raccoon only improved its dexterity by manipulating objects, but, come on - even a dog can clumsily manipulate objects with its paws. There's room for linear improvement, regardless of trees.

    Otters: hardly arboreal and were they ever!? So how is it otters can grab things, pick them up, pluck them apart and so forth? *Googles for "arboreal octopus"... nope... "arboreal elephant"... none...* It seems that many creatures developed good dexterity without trees.

    OK, so the elephant can grab and haul logs. Aha the tree. Shall we say that because an elephant can grab branches (besides food), branches not food must have been the cause of its prehensile trunk?

    Climb first, eat later? I believe effective foraging - i.e. food - more important than evading predators. Raccoons don't eat trees, or pluck the fruits of trees. They take refuge in trees often though not as a rule. They aren't agile climbers either, and don't appear "at home" in trees by a long shot (I can get cherries - they can't!). I really believe raccoons climb only because they can. Like bear cubs. Like homo sapiens.

    Anyway, if we're looking at human hands, the awesome dexterity that allows us to grasp rocks and smash them with precision must have come from something other than grasping rocks and smashing them with precision. What though?


    ***

    @Spuriousmonkey. Here's a neat trick to do with park raccoons: Find a gravel/sand path, and a leering raccoon - you know the kind that try to pull grocery bags from strollers. Throw some birdseed into the gravel. The raccoon eats the seed blind. It somehow feels the seed from the pebbles and sand, paw to mouth, warily gazing elsewhere. Really incredible!
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    a hand or paw will only be able to manipulate things properly provided its function has not been commandeered for some other adaptive purpose (e.g. locomotion such as running, flying or swimming)
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    Quote Originally Posted by Pong
    Quote Originally Posted by i_feel_tiredsleepy
    adaptations to foraging come after.
    It seems you believe being able to handle objects must owe to arboreal mastery first. Climbing trees is that crucial.

    Now I'm not saying the raccoon only improved its dexterity by manipulating objects, but, come on - even a dog can clumsily manipulate objects with its paws. There's room for linear improvement, regardless of trees.

    Otters: hardly arboreal and were they ever!? So how is it otters can grab things, pick them up, pluck them apart and so forth? *Googles for "arboreal octopus"... nope... "arboreal elephant"... none...* It seems that many creatures developed good dexterity without trees.

    OK, so the elephant can grab and haul logs. Aha the tree. Shall we say that because an elephant can grab branches (besides food), branches not food must have been the cause of its prehensile trunk?

    Climb first, eat later? I believe effective foraging - i.e. food - more important than evading predators. Raccoons don't eat trees, or pluck the fruits of trees. They take refuge in trees often though not as a rule. They aren't agile climbers either, and don't appear "at home" in trees by a long shot (I can get cherries - they can't!). I really believe raccoons climb only because they can. Like bear cubs. Like homo sapiens.

    Anyway, if we're looking at human hands, the awesome dexterity that allows us to grasp rocks and smash them with precision must have come from something other than grasping rocks and smashing them with precision. What though?


    ***

    @Spuriousmonkey. Here's a neat trick to do with park raccoons: Find a gravel/sand path, and a leering raccoon - you know the kind that try to pull grocery bags from strollers. Throw some birdseed into the gravel. The raccoon eats the seed blind. It somehow feels the seed from the pebbles and sand, paw to mouth, warily gazing elsewhere. Really incredible!
    I already said that it can be assumed to be an arboreal adaptation because of how common the adaptation is in descidious forest, and the adaptation to arboreal lifestyle is found in other raccoon species where the advanced foraging adaptations aren't.

    Moreover, related genera like coati's retain the aboreal lifestyle, and the closely related smaller species of bears retain it too.
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  28. #27  
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    Quote Originally Posted by marnixR
    a hand or paw will only be able to manipulate things properly provided its function has not been commandeered for some other adaptive purpose (e.g. locomotion such as running, flying or swimming)
    Right. Human feet for example.
    Quote Originally Posted by i_feel_tiredsleepy
    it can be assumed to be an arboreal adaptation because of how common the adaptation is in descidious forest
    OK I guess that's one way of looking at it.

    Besides standing trees, we find forest floor generally very difficult to navigate, with fallen limbs & trunks, branches, thick brush. Some animals, like deer, spring over obstacles. The other option is "hands-on" climbing over/through obstacles (quadrupedally), and you may get the grasping forepaws as a bonus, or keep them (MarnixR's "locomotion"). Humans evolved away from both solutions. Our ridiculous hind legs. We like our forests having lots of smooth ground and minimal canopy breaks to keep the undergrowth manageable. This suggests a very particular type of forest, or none at all.

    I think it more accurate to say the raccoon is adapted to forest floor, than "the arboreal lifestyle".
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