Aquatic Ape Theory

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saw an interesting program on tv the other day. And although a lot of nonsense was mentioned they did manage to say one sentence that was interesting:

maybe it was not quite such a leap to go bipedalism for the human ancestor as we might think it was.

Bonobos for instance spend already a lot of time in the bipedal position in their forest habitat, therefore the arboreal lifestyle might have been not detrimental, but even instrumental in the evolution of bipedalism. Just a slight increase in selective pressure therefore might have done the trick.

 

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I haven't the time to read through all the threads on this subject, but here's my input:

Why is it that humans have webbed feet and hands in their genetic blueprint? Below is an OMIM descriptions of such an anomaly, and there are plenty of others:


*185900 SYNDACTYLY, TYPE I
CLINICAL SYNOPSIS
Limbs :
Syndactyly
Complete or partial webbing between 3rd and 4th fingers
Fusion of 3rd and 4th finger distal phalanges
Complete or partial webbing between the 2nd and 3rd toes
No amniotic bands

Inheritance :
Autosomal dominant

Either our DNA is prepared for what might be possible in the future, or what has already occurred.

And...we certainly are dependent on the essential fatty acids present in the sea for the proper function of our brains. At the very least we should consider that our ancestors were dependent on seafood at some point in our evolution for survival. And if this is the case, perhaps we were able to escape predators, at least temporarily, by escaping into the water. We developed the ability to hold our breath for long periods of time because it facilitated capturing the fish, which is a whole lot less riskier than killing many land animals. Eventually we could swim to offshore islands? Maybe our evolution was accelerated by isolation on islands which other primates were unable to access. An isolated island lacking in vegetation may have driven humans to swimming as their main mode of acquiring food. Hair can slow a swimmer down in the water and it makes sense that humans would evolve with less hair in such an environment. the fittest swimmers lacked hair and passed this gene to their offspring. Jump forward countless generations and maybe the water level changed enough so that the new species of Homo Sapien were then forced to live on the mainland because some predator was able to habitate the island due to shallow water. And maybe we cannot find any links because the islands are now under water.

 

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When I first started reading this thread I couldn't help but cringe. Not at the theory, which I happen to support, but the lack of understanding where evolution is concerned. I think it's so difficult to comprehend because people have trouble considering timespans of millions of years.

No, we didn't come out of the sea. We aren't evolved from mermen. Virtually all land animals are semi-aquatic to some degree. Water is a part of our environment and we must sometimes cross it during migrations or escaping from predators. Most mammals need to frequent water sources to survive. It is more imortant to our bodies than food. Interestingly though, the apes are exceptions to that rule. Most, including chimpanzee's, get sufficient water from their fruit diet. They cannot swim or hold their breaths underwater. Neither do they sweat very much. Survival dictates that excessive sweat glands are a no no for animals in a dry environment like Africa. Unless ofcourse they spend a great deal of time near and in water.

Here is the theory as I read it in The Aquatic Ape. Two main versions exist. I prefer the island theory to the River Apes so will give you the short version of that.

Species tend to mutate into new species when isolated. Millions of years ago environmental change forced new adaptations upon a species of primate ancestral to both Chimps and Humans. A rise in sea level flooded the Afar Triangle of North Eastern Africa wiping out most of the native flora and fauna dwelling there. Survival for apes in the region was a result of both posessing natural genetic advantages over siblings and blind luck. For survivors food was scarce and survival from then on became a daily affair of overcoming new obstacles and finding food.

The environment was similar to the Amazon now. Today, there are only two primates in the World that can swim and they both live there. Our ancestors had to find new sources of food and quickly found shellfish to be a nutritious substitute among the small islands. Frequently, when traditional food sources ran out on a small island, they would be faced with either making a hazardous journey across water to new islands or starving. Each migration had its fatalities as water was a strange and deadly environment for apes. Skip a million years and the picture changes but it isn't as smooth as that.

Several times over the period of mans evolution the isolated region opened up. Sea levels would drop for a time allowing the passage of apes out of the area. It's quite possible some found their way out in trickles during the flood aswell. This explains the large number of different hominids known to suddenly appear in the fossil record. Every time landbridges appeared new apes would leave the Afar Triangle. Chimpanzee's were among the earliest. Most nearly all are now extinct.

The earliest tools are thought to be spears and rocks. Rocks would have been an obvious tool for attacking shellfish. Even otters have learned this trick. Pointed sticks are just bigger versions of the twigs used by chimps today to get at termites. A longer reach for stabbing fish. Adapting to a semi-aquatic environment made us smarter and we quickly adapted our tools to land when the floods eventually receded for good.

"To reason that the semi-aquatic population, which just allegedly spent 1.5 million years specializing in semi-aquatic living could out-compete the same ancestral population that spent the same amount of time further specializing in terrestrial living defies any Darwinian explanation."

The land dwelling apes were already fully adapted for their particular niche. That of arboreal fruit eating climbers. Our diet of protein rich fish and later animals of the savannah allowed us far greater brain capacity. Our many new adaptations proved useful in carving out an entirely different niche. That of top predator. Dolphins compete very well against sharks by the way. For the same reason. Despite Sharks having hundreds of millions of years headstart they are slower than Dolphins, less intelligent, cold blooded and generally lone hunters. Dolphins were like dogs about 65 million years ago. Now they are the most proficient hunters in the ocean.

Until I read AAT I was always at a loss to understand human divergence. AAT isn't at odds with the Savannah Hypothesis. It supplements it beautifully. Everything is explained in a logical manner.

 

When I was 6 I had a branchial cyst removed. It was a one in a million thing and so rare that it was bottled and sent to a large hospital. I was told it was a 'fish gill'.
Background: Branchial cleft cysts are congenital epithelial cysts, which arise on the lateral neck from a failure of obliteration of the second branchial cleft in embryonic development.

"Phylogenetically, the branchial apparatus is related to gill slits. In fish and amphibians, these structures are responsible for the development of the gills, hence the name branchial (branchia is Greek for gills)."

 

Cthulhu

Everything is explained in a logical manner.

Is that why paleoanthropologists refute the AAT? Can you add anything other than hand waving?

 

Cthulhu

Our diet of protein rich fish and later animals of the savannah allowed us far greater brain capacity.

That would make crocodiles the most intelligent animal on Earth. Surely you must have something better than this.

 

fish in savannah regions? these type of regions is typically dry.
crocs? sure. but is it a typical habitat?

Between the wet equatorial belt and the subtropical desert regions are areas known as Savannah. They have a single short rainy season when the Sun is nearly overhead, whilst the rest of the year is dry. Vegetation consists mostly of scrub and grassland, which blossoms during the rainy period, and dies off during the prolonged dry season. Such climates and their associated land types are common in the Sahel in Northern Africa (south of the Sahara), large parts of India and parts of northern Australia.

i imagine it was pretty much the same during the pliocene

Dr Michael Crawford of the Institute of Brain Chemistry and Human Nutrition, London, Dr L Broadhurst of the USA., and other collaborators presented an unexpected and fascinating study. In his book The Driving Force: Food, Evolution and the Future (1989), Crawford explores many issues around "the land-water interface". To develop the large brain characteristic of the hominids, a chemical known as DHA was necessary. The lack of DHA in savannah food may explain the "degenerative evolution" of the brains of savannah species and the reason why Homo sapiens could not have evolved on the savannahs. The marine food chain, on the other hand, has an abundant supply of DHA. Early hominids had to make use of the marine food chain to enable the evolution of brain and brain size to keep pace with body size. Their claim that the human brain depended on the marine food chain suggests independent evidence in support of the importance of water in human evolution.

http://allserv.rug.ac.be/~mvaneech/outthere.htm


dispute the points that were put forward against a savannah scenario if you wish to maintain the hypothesis

edit: link inserted to counteract the heinous charge of eloquence

 

Not all palaeoanthropologists refute the AAT. It has recently seen a resurgence in interest. Evolution was refuted by most scientists in Darwins day. It takes overwhelming evidence to overturn theories many professionals have staked their professional careers on. At present there is little fossil evidence to support AAT. Which in fact would be expected since no digs are being undertaken at promising sites in the Afar Triangle.

I said that a high protein diet is necessary to support a large brain. I did not say eating a high protein diet automatically leads to development of larger brains. Spookz has eloquently explained it much further. We faced a challenging new environment which was intellectually demanding on us. At first we probably scavenged food left by the falling tide of this new inland sea. Later we became more daring and ventured out in search of it. The pearl divers of Japan demonstrate our remarkable talent for this. Our first adaptation would have been proficient wading ability. Keeping our heads above water and occasionally dogpaddeling back when it got too deep. This bipedal posture we posess didn't happen without an incentive. The same two primates who swim in the Amazon today have also been observed to wade in a similar fashion to human walking.

There is nothing unusual about this semi-aquatic behaviour. It is a common occurence in the mammalian kingdom for animals to return to water. Otters are a great example. Genetically they are almost identical to weasels. Divergence would have been very recent for the two. This new "water weasel" still shares much of its land cousins breeding customs. A male weasel for example grabs the female by the back of the neck during mating. Hard enough to draw blood. Otters mate in water where it is safer to mate face to face. As a consequence zookeepers know when breeding time has arrived because the female otters all have bloody noses.

Incidentally, we are the only ape to mate face to face. Certain evolutionary plumbing changes had to be made to make this form of copulation possible.

It's not just mammals either. In fact the only other creature in the animal kingdom to share our straight body gait with head balanced centrally atop the spine is a bird. The penguin. Another semi-aquatic.

 

Cthulhu

Not all palaeoanthropologists refute the AAT

Aside from the crackpots, yes. No credible palaeoanthropologist support it.

At present there is little fossil evidence to support AAT.

None exists.

The pearl divers of Japan demonstrate our remarkable talent for this

My neighbors dog demonstrated that too – so what?

Our first adaptation would have been proficient wading ability. Keeping our heads above water and occasionally dogpaddeling back when it got too deep. This bipedal posture we posess didn't happen without an incentive. The same two primates who swim in the Amazon today have also been observed to wade in a similar fashion to human walking.

Wading is proficient, but only to predators. Swimming is more efficient and precludes the need for bipedalism.

Incidentally, we are the only ape to mate face to face. Certain evolutionary plumbing changes had to be made to make this form of copulation possible.

False. We are not the only animals to practice ventro-ventral copulation – look it up.

The penguin. Another semi-aquatic.

That’s a funny one. The penguin is a bird and was bipedal before it was aquatic. By the way, what living semi-aquatic animal is bipedal?

Your argument is very weak and it appears you’re simply parroting Elaine Morgan and her followers.

 

Chimpanzees' and humans' most recent common ancestor is thought to have lived in Africa around 6 million years ago. This estimate is based on differences between the DNA and other biomolecules of modern apes and humans. Fossil evidence is scant, and controversial.

Until February of this year, the earliest known hominid was Ardipithecus ramidus, which lived in Ethiopia around 4.4 million years ago1, some time after the divergence.

Then researchers working in Kenya claimed to have found a 6-million-year-old hominid; they called it Orrorin tugenensis2,3. Provocatively, they suggested that Ardipithecus ramidus was not a member of the human lineage at all, but was more closely related to chimpanzees.

The new finds, announced today by Yohannes Haile-Selassie of the University of California, Berkeley4, support the hominid status of A. ramidus and cast doubt on that of Orrorin. The fossils, from the Middle Awash area of what is now Ethiopia, represent an early form of A. ramidus, the team believes.

The resolution of this debate, if any comes, may have surprising consequences. At least one of these very ancient creatures could, in fact, be more closely related to chimps than humans. This would be an exciting result: fossils of hominids are notoriously rare, but fossils of chimpanzees are non-existent.

The same seems to be true for the older Ardipithecus announced today. Everything points to a woodland habitat for hominids living 5-6 million years ago, say Giday WoldeGabriel of the Los Alamos National Laboratory, New Mexico, and colleagues7. Orrorin seems to have shared this taste.

http://www.nature.com/nsu/010712/010712-14.html

 

why does aat and savannah have to be mutually exclusive? does affirming one theory automatically discount the other? as indicated in the nature article, including a woodland habitat would bring us closer to a mosaic type scanario. i believe there was a reference to the mosaic in an earlier post. all indications are that the savannah was an inhospitable region for hominids. this does not have to mean it was not populated.

the next article is especially for you brother q!

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The Aquatic Ape - in from the cold?


My critics said AAT was unnecessary. They claimed that the scenario for the ape/hominid split was well understood: one population of the ancestral apes moved from forest out into the "hot, dry savanna". There, they became two-legged so as to "run faster" and carry weapons, while the torrid heat caused them to sweat profusely and shed their body hair. AAT referred to all this as "the savanna theory". In different versions, it reigned supreme for over fifty years.

In what for me has been a remarkable and exciting development, the experts have in recent months suddenly started to abandon this whole idea. Detailed studies of the African paleoenvironment show that savanna conditions evolved in Africa much later than had previously been imagined. The habitat of Lucy (Australopithecus afarensis) is now agreed to have been "lush and well watered" (her bones lay among crocodile and turtle eggs and crab claws).

Australopithecus ramidus, a million years earlier still, lived in woodland. Richard Leakey wrote in 1992: "The great plains and the immense herds on them are... much more recent than the origin of the human family". And now Professor Phillip Tobias, lecturing in London on his recent fossil discovery "Little Foot", has announced that "the savanna hypothesis" (of which he had been one of the most illustrious supporters) "is washed out".

Is this the beginnings of a paradigm shift completely revolutionising our understanding of human origins? I think it could be. The strength of savanna theory lay in its contention that the hominids' habitat was radically different from that of the apes. This claim is severely undermined if the protohominids were largely tree-dwelling, as is now agreed, only crossing open spaces in occasional transit from one patch of forest to the next.

Meanwhile, AAT is waiting in the wings. The arguments against it look increasingly precarious. Nearly all the Rift Valley fossils were recovered from lake or river sediments. Unfortunately, this can never prove that the entire species lived by the water, since only bones deposited in watery sediments get preserved. On the other hand, neither can it disprove the idea. If the first hominids were indeed largely tree-dwelling, why did they and no other apes become bipedal on the ground? A flooded forest offers a possible answer: there is geological evidence of extensive flooding in the areas where the oldest hominids are found.

The strongest argument for AAT is the number and variety of Homo's unique features, for some of which the aquatic explanation is the only one on offer. These anomalies are not a common subject of research. Many specialists still find them simply distracting, and sometimes respond "We may never know the reason" or even "There may not be a reason".

But the questions will not go away. Professor Tobias enjoys being back at square one. "A change of paradigm", he says, "shakes us up; it rejuvenates us; and this above all, it prevents mental fossilisation - and that is good for all of us". (morgan)

http://www.llb.labournet.org.uk/1996/april/sci.html

i would like to be able to dispute her claim of a flooded forest and wading as an impetus towards bipedalism.

 

As far as I know there have been no expeditions to the Afar Triangle in an effort to find evidence. I wonder if enough support and funding could be gathered for such a venture. It might prove fruitless but if successful would revolutionise anthropology. Theories regarding human origins would have to be rewritten. I'm only an amateur Palaeontologist but it might depend on recruiting enthusiastic amateurs. I'd be more than willing to make such a trip myself. How does a person go about arranging this kind of adventure? You only have to do a search to discover that squillions of people would volunteer for it. Money is the only problem. Approaching potential sponsors might work. Otherwise I could establish a fund and beg for donations I suppose. One good thing about the internet is Paypal.

Destination for the dig? Danakil Island most likely.

 

Cthulhu

I see you've returned as SciAuthor. Is there some reason for the deception? Are you going to advocate your own AAT assertions? I find it hard to believe my last post was the definite nail in the coffin, so to speak.

What gives?

 

Just my opinion on the AA theory... I think it has lots of relevance but needs more proof before it can topple the existing theory. It would explain body fat layout, head hair spiral, webbed feet, and our strange lack of normal primate body hair!

 

i take it you aint caucasian huh?

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Nope how you guess... but latinos have that kind of hair too (just worse!) very VERY few people have hairs as thick as a chimp though.

 

No deception. I just didn't like the look of Cthulhu1. I'll try to answer your last post then. Your statements were so definitive I assumed you wanted no reply.

"Aside from the crackpots, yes. No credible palaeoanthropologist support it."

Untrue. Some leading scientists support it. Majority is no indication of correctness.

I said...
At present there is little fossil evidence to support AAT.

"None exists."

Untrue. Shells have been discovered from the time period relevant with scratches identical to those which would have been made by early hominids. Proof that they supplemented their diet with shellfish. Countless physiological traits match those to be found in semi-aquatic animals. Why did our ancestors jaws and teeth diminish? Clearly shown in the fossil record. A diet change from fruit to tough meat would not lead to weakened eating apparatus. Even Lucy was found in an ancient lakebed. How is it that fossil man is found in almost every part of the World. Apes have a natural fear of deep water. Some places were only crossable by sea.

The pearl divers of Japan demonstrate our remarkable talent for this.

My neighbors dog demonstrated that too – so what?

Try teaching a Gorilla.

Our first adaptation would have been proficient wading ability. Keeping our heads above water and occasionally dogpaddeling back when it got too deep. This bipedal posture we posess didn't happen without an incentive. The same two primates who swim in the Amazon today have also been observed to wade in a similar fashion to human walking.

Wading is proficient, but only to predators. Swimming is more efficient and precludes the need for bipedalism.

No doubt. But you must walk before you can run. People who cant swim wade. Its easy. We have the natural balance of a sea lion. Standing tall keeps your head out. As I explained, this is eactly what two species of monkey do in the Amazon. Swimming and diving came next.

Incidentally, we are the only ape to mate face to face. Certain evolutionary plumbing changes had to be made to make this form of copulation possible.

False. We are not the only animals to practice ventro-ventral copulation – look it up.

I said Ape.

The penguin. Another semi-aquatic.

That’s a funny one. The penguin is a bird and was bipedal before it was aquatic. By the way, what living semi-aquatic animal is bipedal?

I know its a bird and said so. Bipedalism was not what I said. Its body is straight like ours. Head situated directly above the spine. An unusual trait only shared by us. Another aquatic. Perhaps just a coincidence. Perhaps a case of parallel evolution.

Your argument is very weak and it appears you’re simply parroting Elaine Morgan and her followers.

AAT is far more logical than the Savannah hypothesis standing alone. Look at Babboons and you will see the results of savannah on Apes. Our physiological makeup shares little with Babboons and no major evolutionary changes happen without being forced. How could predators have instilled such change? We are slow running, sweat profusely, are fat, have no sharp strong teeth or claws. How did we survive before tools were invented? The only other possible force of change is environmental. A drastic change in the land. Only flooding fits and we know north east Africa was flooded at the right time.

 

birds went bipedal because of an adaptation to flight. Therefore they cannot really be used as an example for aquatic bipedalism. The aquatic adaptations in penguins are secondary adaptations. That said, there doesn't have to be any analogous example of a bipedal semi-aquatic animal to proof that humans bipedalism was facilitated by a semi-aquatic period. We could have been the single example ever and it would still be valid.

I think that most people make the mistake that there is plenty evidence for any of these theories. This leaves the suggestion that the evidence for the AAT is so weak that the savanna theory must be right since there is so much evidence for that. But of course there isn't really.