No physical evidence. Well, there isn’t a lot of physical evidence of Proconsul or Australopithecus anyway.
Humans can’t drink salt water. You’d think that if we evolved there, we could drink the stuff (or, get out water needs from our prey like sea otters, seals & such do). And, humans aren’t adapted to live off just littoral animal life, either. Clearly early proto humans ate some veggies too.
But the big sticking point is- if we adapted to live there, why’d we leave?
However, I have an idea which may conserve the 'good points" of the AAH and egt rid of #'s 2 and 3.
Lakes. Shallow lakes. They are perfect. Plenty of various kinds of food- animal, vegetable, and so forth. Few predators other than the crocodile, and stone-age humans can & did kill (and eat) crocs. Plenty of water. The prey comes to you.
And, what’s bests is that there was (I think) a huge change in the environment around then where Africa dried up a lot. Thus, Aquatic apes would be forced out of their lakes-now-mud-puddles and into land dwelling.
Ok, I admit we still have problem #1. But other than that?
OK, you’ve shown that it’s possible. The big challange is showing that it’s more likely than the Plesiocene Pussy Cat theory, which is also possible. And if you can manage that, then for an encore you can show that’s it’s better than the currently-accepted models of anthropological development.
The Aquatic Ape Hypothesis is an idiotic speculation–I won’t refer to it as a theory proper–and attempting to Band-Aid some of its most egregious oversights doesn’t really improve it any. The main argument against it is that it postulates a major evolutionary change over a very short timespan; there is no span of human evolution from australopithecines and modern human longer than 250,000 years that isn’t accounted for. To assert that in that time the forebearers of H. sapiens developed aquatic features and then deprecated them to a point that we’re no longer effectively able to sustain life indefinately in the water is the height of absurdity; it sounds more like a Monty Python skit (“And now it’s time for the Aquatic Ape Invasion”) than a serious theory in evolutionary anthropology.
In fact, the AAH really has one purpose; to establish an alternative explanation for upright posture and bipedal movement. It fails miserably at that–there are plenty of other reasons for bipedal plantigrade mobility that do not require the kind of logical articulation to support proported aquatic features–and most of the claims that are made in support of the AAH–the orientation of hair, mammalian diving reflex, existance of subcutaneous fat, et cetera–are either mistruths or misapprehensions about the utility and existance in humans and other mammals. Examining true aquatic mammals such as the sea lion, orcas, sea otter, et cetera one sees clear evolutionary adaptations that humans do not possess; not only obviously displayed phenotypes such as flippers, webbing, protective eye cover, et cetera but also the ability to process sea water, a requirement for a high fat, high protein diet, and so forth. Humans, like other apes, cannot tolerate even moderately saline water for internal consumption and require a moderate protein, high carbohydrate, high fiber diet for good health.
Even if we’re assuming, as you do, that the theoretical aquatic ape was a creature of fresh lakes or brackish marshland, you still have to account for our inability to retain heat, our mediocre ability to swim, our difficulty in extended breath holding, et cetera. Certainly many cultures evolved near sources of water–aside from the obvious uses, it also contains a renewable food source and often offers easy transportation–but there’s essentially no evidence in favor of the AAH.
What the OP does is the commonest scientific fallacy found on the Dope and by extension by all amateurs who try to take on science. They try to state science in words and think that they’ve said something meaningful.
It doesn’t work this way. Words are not the language of science. Mathematics is the language of science, with physical evidence being the substitute when pure math is not appropriate.
Merely saying that lakes exist, therefore aquatic humans were possible, is the ultimate in hand-waving. It says nothing. It certainly isn’t science, and isn’t even the start of an approach to an answer in science. The OP gives no reasons of any sort, let alone physical evidence, that would connect the two statements.
The damaging aspect of this fallacy is that it means that the people who use it don’t understand why scientists just brush off the fallacy with contempt rather than making what would be, to them, a reasonable effort to evaluate it. It isn’t reasonable for them to expect anything of the kind, of course: it would like asking Jefferson to throw in some meaningless mathematical gibberish into the Declaration of Independence and about as useful.
This is what people talk about when they say that the U.S. is destroying itself through the lack of scientific education. It’s not that people need to know more facts about science, however wonderful that would be, but that they need to know what science is and looks like at the most basic level to understand what scientists say and why, and what scientists don’t say and why.
This is independent of the dubunking arguments that SoaT gave. Those are always useful, too. I just think more and more these days that without more education in what science looks like, mere debunking is nowhere near enough.
Nonsense. The AAH is a theory. It may not be valid of course. But it’s still a theory. Saying that a theory that you don’t hink is very likely is wrong- even though you have no solid evidence it’s wrong- is also bad science.
You mean to say that it’s a hypothesis. (Says so right there in its name, even.) As a hypothesis, it should be tested and verified, falsified, or perhaps found to be lacking in sufficient evidence to do either, which would practically mean that it would have to be laid aside. I’ll leave it to you to draw connections to any other hypotheses currently being misportrayed as theories in the news…
To which specific claims are you referring? If you mean the rapid evolutionary change to and then from an “aquatic” form, that would be implicit in the argument, as noted in bibliophage’s excellent and throuroughly debunking Staff Report on the issue. I note that he indicates the hypthetical Aquatic Ape transition to be prior to Australopithecus, whereas my reading on the topic indicated that it happened somewhat after that phase; there is clearly a lack of agreement, or indeed, definition at which period this rapid transition occurred, which is understandable given the complete lack of any fossil or genetic evidence to support this hypothesis. Nonetheless, this change must have occured sometime between now and the divergence of H. sapiens from chimpanzee, generally taken to be 7 million years. There is no gap in the fossile record sufficient to plausibly explain the development and subsequent deprecation of features found in all other marine mammals.
Nonsense. Even in tropical waters–we’ll use 85 deg F as a working number–long term submersion will result in heat loss, regulatory failure, and shock. Mammals evolved to survive indefinitely in water have a number of thermoregulatory adaptations that permit them to maintain body temperature, but the most important of them is vascular constriction, i.e. the ability to limit the amount of blood delivered to extremities to reduce heat loss. Humans, on the other hand, are evolved to waste away excess heat (note our rosy cheeks, red noses, et cetera) which is what you’d expect from a land animal that developed in a tropical or subtropical savannah. Here and here are abstracts to peer-reviewed papers on thermoregulatory mechanisms in marine mammals.
In order to be a theory, it has to be falsifiable; that is to say, you have to put forward specific claims that can be tested for disproof via physical evidence, observation, or experimentation. The Aquatic Ape Hypothesis fails this definition; its proponents cannot present even a shred of fossil evidence. None of the stated claims in pursuit of AAH are either limited to marine mammals nor necessary for the development of modern human features. It certainly doesn’t satisfy its primary purpose in rationalizing bipedalism; there is not a single aquatic mammal that displays anything like bipedal motion. AAH doesn’t even stand up to the most casual challenge; it provides no explanation for any phenotype that isn’t easier and better explained by other influences, and many of the claims (of the apes only humans have subcutaneous fats, of mammals only humans have voluntary breathing control, et cetera) are patent bullshit.
Exapno Mapcase has it right; to believe, or promote the belief, that all claims are equally valid as “theories” is bad science and demonstrates a lack of critical thinking. All cats may be black at midnight, but that is only because the investigator is unable or unwilling to turn on the light and make even a cusory test of the claims. Critical thinking and the willingness to demand strong evidence in the face of extraordinary claims is a prerequisite to any kind of scientific process, and the inability of apologists for AAH to provide anything but hand-waving arguments and claims that their pet “theory” provides the only comprehensive explanation (despite its manifest flaws and lack of evidence) indicates more to a counter-establishment dogmatism than any serious scientific theory.
This isn’t to say that it can’t be true; it is (implausibly) remotely possible that protohumans could have gone through a rapid aquatic-adapted phase, but the utter lack of physical evidence in support of it, combined with the extreme unlikelyhood of having developed the requisite features and then dispensed with them in an astonishingly short period of time such that humans are one of the least capable mammals in water makes it nearly impossible to take these claims with any seriousness. Extraordinary claims require extraordinary evidence, not vague, unfalsifiable speculation based largely upon misapprehensions of human physiology and mammalian zoology.
The difference is that there is no “Australopithicus theory”. There is a “savanna ape” theory and Australopithicus is evidence of that.
The point is that for a hypothesis is scientific it needs to be based on observed evidence. Or more simply you have to have some evidence that what you seek to explain actually exists.
Yes, they catch them from land or using boats. No stone age human has ever captured or killed croc while standing waist deep in water. Yet your ‘explanation’ requires that humans be able to kill crocodiles in exactly that environment. How could that be possible?
The problem you haven’t addressed is that humans are hopeless swimmers. And if a walking/running human can catch prey in the water why couldn’t a leopard? And if a leopard can catch prey in the water doesn’t that mean that there are many predators aside from crocodiles?
You’ve added yet another layer of complexity to try to plug the gaps in a hypothesis that already suffers from no evidence and fatal flaws. For this latest band-aid to work we need to accept that somehow these hominids were better at hunting in waist deep or deeper water than they were on dry land. How could that be?
So your hypothesis posits a forced movement of an aquatically adapted hominid onto dry land in the middle of a continent already filled with both competitors and predators exquisitely adapted to dry land and dry conditions?
And this makes more sense than a movement from forest to savanna how exactly? At least a forest species is already adapted to movement on land and only has to cope with drier conditions in a new environment. Your hypothesis requires the species to deal with not just a new environment and drier conditions but an actual transition from an aquatic to a purely terrestrial lifestyle.
Once again, this is just an added level of complexity for an already baseless and ailing hypothesis. The major reason for the AAH was that you think that upright posture was unlikely to be adopted on the savanna because it is to unwieldy in the early stages. Yet somehow enforced movement form aquatic to terrestrial environments is less unwieldy? How?
As bibliophage’s report mentions, at the time the hypothesis was originally formulated there was a 10 million year gap between Proconsul and Australopithecus, allowing lots of room for speculation. Much of that gap has now been filled in, making the hypothesis completely untenable, even if the supposed arguments in its favor had any substance to them.
I thought bibliophage should have also addressed the Flying Monkey Hypothesis (FMH). Clearly our ancestors took to the sky, or they would have been consumed by lions, tigers, and other large predators. It also aided them in their competition with H. Stannous.
I’m not sure exactly where the “aquatic phase” of our evolution would have taken place, but if it was in the lakes and rivers of Africa (as I would think would be the natural assumption,) there’s at least one other major problem with the AAH.
We’d have gotten our asses kicked in short order. Nile crocs and hippos would have been resource competition, and we aren’t evolutionarily suited to taking on either of them in the water.
[QUOTE=Exapno Mapcase]
There is no “other than that.”
Merely saying that lakes exist, therefore aquatic humans were possible, is the ultimate in hand-waving. It says nothing. It certainly isn’t science, and isn’t even the start of an approach to an answer in science. The OP gives no reasons of any sort, let alone physical evidence, that would connect the two statements.
QUOTE]
The OP didn’t say “lakes exist, therefore AH were possible.” Rather, the OP said, “The existence of lakes indicates that points number 2 and 3 in my OP do not disprove the possibility that AH existed.”
That’s very different, and your criticisms do not apply.
FWIW, the only form of the “theory” I’ve encountered is the fresh water one. Adding a trivial objection to the scholarly ones already mentioned, have none of the proponents of this theory ever spent a couple hours in the water? And wrinkly skin was adaptive how?
Your explanation is at cross purposes here: you say the AA hypothesis is not falsifiable and then say it makes claims that are patently bullshit. That is, false claims. Perhaps it is better to say that the AAH is scientifically testable and in fact has been found false.
