atrahasis

Hey guys,
The origin of mankind has remained a mystery for many years. Many scientists and archeologists have tried to explain this bizarre topic but left out crucial aspects which might be necessary to complete their arguments.A very avoided theory of man originating from the sea has caught my attention....Im not claiming it is the Truth but rather a possible truth...So lets look at this with open minds and tread on the untouched....I will be eager to hear what you guys have to say about this..

The links below might be useful:

<a href="http://www.riverapes.com/AAH/AATheories/Wading/why_did_we_start_walking.htm" target="_blank">Walking or wading</a>
<a href="http://allserv.rug.ac.be/~mvaneech/Fil/Verhaegen_Language_SpeculationsScienceTechnology.h tml" target="_blank">Aquatic ape theory and speech origins</a>

<a href="http://www.riverapes.com/AAH/" target="_blank">Most authorities on Human Evolution agree that the last common ancestor of Chimpanzees, Gorillas and Human Beings lived in Africa at the most 8 million years ago. </a>

Counter arguments::

<a href="http://www.riverapes.com/AAH/Arguments/index.htm" target="_blank">Arguments and Counter-Arguments about the AAH</a>

--Thanks--

--Let the wise teach the mystery to the wise--

[ September 13, 2002: Message edited by: Black Moses ]</p>

Duvenoy

Hi Black Moses,

I will leave this to be pulled into quivvering chunks of bloody flesh by those more learned than I. But, I have a couple of points.

Breath-holding in primates is learned. There is a population of Maquacs in Japan that regulary dive in the shallows for food.

Bi-pedal locomotion is indeed handy for sloshing around in the shallows, but it is also highly advantagous in the predator populated, high grasses of the African savannahs.

Most instances of heavy subcutainous fat, these days, comes from too much Mickey D's and other grease pits of similar ilk, and not enough excersize. In mideavl(sp?) times, mostly only the wealthy could become fat. It seems unlikely that the diets and activities of our ancient ancestors would produce a lot of lard on such a hunter / gatherer / scavenger.

Sweating is simply thermal regulation of the body. An excessivly fat animal would have difficulty in a hot enviornment. Elephants look fat. They are not. Hippos are, but they are pretty much aquatic, mainly coming ashore at night to graze.

Ok. There's mine.

Let the games begin!

doov

seanie

I thought the diving reflex only occured in humans. Is that correct?

Stephen T-B

I’ve interviewed Elaine Morgan at her home in Wales, and I came away thinking the suggestion she supported was pretty sound. (When first I heard it, I dismissed it as total rubbish.)
She has points: the Savannah story which is supposed to explain why humans became bi-pedal and lost most of their body hair is incoherent in so far as no other savannah species acquired these adaptations.
Her arguments about early humans appearing on the shores of an ancient inland sea in the heart of Africa seem also to be justified.
More recently her case received some support when a bunch of naturalists who were studying a colony of lowland gorillas noted that they spend quite a lot of their time up to their chests in a swamp, standing upright so as to be able to pluck the vegetation with their hands.
But the AA explanation for depositions of human body fat and our hairlessness, by comparing these features with other semi-aquatic mammals, is not so convincing, for why are seals and otters covered in fur?
In her original book, Elaine Morgan made some rather daft suggestions eg. we - specifically women - evolved the characteristic of growing long hair on our heads because this was an assistance to babies when floating around in the water and needing something to grab hold of. I think she’s now dropped that idea.
I was, I have to say, disappointed that the AA hypothesis was being dismissed out-of-hand by the scientific community, principally, it seemed, because its chief advocate was a mere writer: as though a mere writer is unable to conduct valid research.
I do now think, however, that there are serious flaws in the hypothesis, but the alternatives seem even worse.
And I cannot fail to be impressed by the way human beings are drawn to water, not only to live by (a practical need) but to get food from and to use for recreation. Chimps - one of the points Elaine Morgan makes - so dislike water that they will not attempt to escape from an island if they are put on one in a zoo. Just put them on a bit of land, dig a moat around them, fill it with water and hey, you’ve a captive colony.
Clearly a great deal more work needs to be done in terms of finding out why we have evolved the way we have done, but Elaine Morgan is to be commended for her thought-provoking contribution.

Oolon Colluphid

That’s what I’d heard too...?

Ref subcutaneous fat, it looks to me more like an adaptation to intermittent food supply (inefficient early hunting?).

In reading the utterly brilliant <a href="http://www.amazon.com/exec/obidos/ASIN/0141001828/qid=1031829740/sr=2-1/ref=sr_2_1/104-1332721-3551135" target="_blank">In the Heart of the Sea</a>, I came across the idea that the reason eg Hawaiian and other Pacific islanders tend to get fat easily is that their ancestors made long hazardous boat trips to get there; only those that had / could easily lay down fat, or had slower metabolisms or whatever, survived that selection process. I gather this goes by the name of the ‘thrifty genotype hypothesis’. It seems reasonable that a propensity to store fat when there was food to be had would be advantageous to an ape that was moving towards hunter-gathering from mere gathering.

Or whatever scenario you like... all you need is an irregular food supply for selection to weed out those who can’t survive hard times. IOW, it doesn’t have to be anything to do with an aquatic lifestyle.

Cheers, Oolon

PS Philbrick’s book is strongly recommended to absolutely everyone. It’s not the sort of thing I normally read, but I was enthralled more than by just about any novel even.

Wyz_sub10

Stephen, if you've interviewed Morgan you've likely got a better handle on this than I do, but I still see several problems with the AAH theory based on the points it makes.

Man as exceptional swimmer: for starters, we're not. Pretty much all terrestrial animals can swim. Most can do see because they float horizontally. We float vertically, submerging our nostrils. So we learned to swim, but we're not built for it.

Diving reflex: This exists, and probably does in most mammals, but that's about it. We cannot lift ourselves to the surface to breath or swim well when very young.

Loss of hair: This is an odd one because, as has been pointed out, many aquatic animals have hair. Further, though, is that fact that hair is quite a good insulator, even underwater. Why lose this?

Design of the body: Our shape is nowhere near ideal for an aquatic environmet (although better tha giraffs, I suppose). As for walking erect, I doubt man learned to walk erect in water. Many primates do walk erect when wading, but often walk erect on land as well. This proves nothing, of course, but I wouldn't use this to establish a link.

Subcutaneous Fat: Probably more due to our sedentary status and the fact that we are "domesticated". Fat is a crappy insulator.

seanie

Criticising the theory because were not 'ideally' suited to an aquatic environment hardly seems fair.

Surely the argument is that we evolved in a way that was 'better' suited to the environment.

'Ideal' adaptation seems a high hurdle.

Not that I'm in a position to judge whether or not the theory itself convincingly demonstrates this.

Vorkosigan

The theory is trash and has been known to be trash. Lots of animals have subcutaneous layers of fat. Hymens are found in many terrestrial mammals, such as dogs, guinea pigs and elephants. As for "no other animal" having those adaptations, elephants, rhinos and hippos are relatively hairless, and bipedalism is found in savannah animals such as kangaroos. No animal has the exact package of human adaptations, but then if it did, it would be human. In fact, come to think of it, several million years ago there were a large number of primates of the genus-s Homo and Austrolapithecus wandering around on the savannah, bipedal all. So Morgan is wrong, several animals had that adaptation.

It is hard for me to imagine bipedalism evolving among the four-footed creatures of the African savannah!

The diving reflex is found in all mammals, it is more highly developed in sheep than in H. sapiens. We, on the other had, have no demonstratable water adaptations. Consider our external ears, and the fact that we continue to breathe when unconscious, as opposed to water-adapted mammals, which do not.

Michael

Peez

Define "mystery". Like everything else, there are things that remain to be worked out, but I would not describe it as any more mysterious than most other evolutionary lineages. This sounds suspiciously like the same sort of argument that a creationist might make. I certainly don't see it as a "bizarre topic". "Very avoided"? Is that an effort to make it sound as if scientists are "avoiding" this idea for some reason other than it isn't very good? So is the sudden creation of the universe about 6,000 years ago (with the appearance of much greater age, by some perverse god or gods). I did. It is an interesting thought experiment, but does not merit serious scientific consideration (IMHO). Sorry if I sound a bit dismissive, I have seen this brought up a number of times. Rather naively, I would argue. Bzzzt! Sorry, but humans are apes. This is a curious argument. Is it being suggested that the differences between humans and other apes is more environmental than genetic? Or is it simply being argued that the human lineage evolved rapidly in some parts of their genome? Neither of these would be unique to humans. In any event they would not be evidence for the AAT. I don't know that "drastic" is required here, but certainly a change in habitat and/or way of life would be likely candidates for causes of the apparent change in patterns of selection. That is not because these features are inconsistent with the standard savannah model. Rather it is because there is currently no way of testing such hypotheses. One could easily reverse that statement: the savannah hypothesis noted that some of these features, while unique among aquatic mammals, could be readily found among mammals which had remained on land. Most aquatic mammals are not naked (muskrat, sea lion, otter, etc.), while many terrestrial ones are naked (elephant, rhinoceros, human ). Fat under the skin is pretty much universal in mammals. Remember that bit about traits that are unique among land mammals? Did it not occur to this person that bipedalism is unique among aquatic mammals as well? Our particular form of bipedalism is actually pretty crappy for moving about in water unless it is really shallow (c. 30 cm = 1 ft). Just try running in water 1 m (~1 yd) deep, or even deeper. It becomes easier to swim, and it is hard to imagine how being bipedal helps us to swim. If you want to argue that being bipedal allows us to stand in deeper water, perhaps you should consider that typical aquatic mammals float easily and do not have to worry about standing to keep their head above water. Bipedalsim makes no sense here. Primates will adopt bipedal locomotion any time they need to get taller, and they rarely cross a stream on the ground. When they do, they typically jump from rock/log/land to rock/log/land rather than wade through. Apes walk bipedally whenever they are using their hands for something else (e.g. carrying something, or fighting). This is a stretch (to say the least). One must define "voluntary", provide evidence that it is lacking in terrestrial mammals, and explain why it is required for speech. It seems pretty obvious that terrestrial mammals can vocalize (do you have a dog? A cat?). Less obvious is that terrestrial animals can hold their breath (I have seen a dog dive under water). Of course, it is possible to talk without any control over your breathing (people with ‘artificial lungs' demonstrate this). That is obvious. It is always possible that this is true, of course. It just may be that none is called for, when a satisfactory one that fits all the data has already been studied and widely accepted. This does not mean that no new hypothesis should be considered, but it does mean that the burden is on proponents of the new hypothesis to demonstrate that it fits the data better. The AAT has failed in this regard. Again, humans ARE apes. No more closed than many other areas of science. Everything in science is tentative, at least to some degree. However, that does not mean that we should waste our time on every naive hypothesis that is thrown up. The burden of evidence is on the proponents of a new hypothesis. This betrays an ignorance of the mechanisms of evolution, or a biased view. The issue is whether the cost of lost water and salt is greater than the cost of overheating. Note that humans have survived on the savannah (and in even hotter and drier places) for thousands of years at the very least, suggesting that their physiology works fine there. One might also wonder, if natural selection was working against sweating under such circumstances, why we have not evolved away from sweating since we allegedly returned to land? One might also wonder why we cannot obtain water from sea water. LOL! Humans living in hunter-gatherer societies were not as fat as we are today, and in any event stored fat is energy-rich (so carrying it is hardly a disadvantage, until you have a huge amount). Plus: is the author suggesting that aquatic humans had their fat carried by the water? To be in deep enough for that, they would not be standing on their bipedal frame. They could try to swim, but then why are they bipedal? By the way, the distribution of fat does not streamline us (compare a fat human with s seal). Such arguments are deeply flawed, to say the least. The reasons that no one hypothesis for the specific mechanism by which we evolved bipedalism has been universally accepted (as far as I know), are 1) it was likely not just one mechanism, rather there were probably several factors, and 2) there is no way to currently test them. On the other hand, the AAT does not agree with the data and offers no new insight.

Perhaps you should ask the AAT people why we get water in our nose and ears when we swim. How about asking why we have such prominant external ears. Why do our nose holes point down? Why do we loose heat so quickly in water (despite that fat layer)? Why is there not a single aquatic mammal that looks even remotely like us? The AAT is a cute idea, fun to think about, but quite naive. It does not merrit serious scientific attention.

Peez

Duvenoy

Ok, short and sweet.

Our species is so successful because we are strictly non-specialists. We can thrive almost anywhere. We can and do eat almost anything. We are social, grouping together for mutual benifit. There is no reason to think that our ancient ancestors didn't occupy marshland as well as savannah as they spread out. And very quickly adapt to it.

For an example, I produce the Eskimo. These people are rather short and all but round in apperance, ideal for a people living at the fridged top of the world. They once ate a lot of seal and whale blubber, a diet that would not be in the best interest for the rest of us. But today, Eskimos can be found in cities and have adapted to a different diet and enviroment.

The Eskimo comes from the same stock as thee and me: an insignificnt, ape-like creature of the African savannah that looked and acted like none of us (except perhaps, one of my neighbors).

I see little evidence for an aquatic origin of our species; only evidence of adaptation.

doov