The Repercussions of Aquatic Ape Theory (originally written in 2006, amended in 2016)
A repeated two-part programme on Radio 4 in 2006, hosted by David Attenborough, attempted to resurrect the Aquatic Ape Theory of human evolution by adding new evidence to the already impressive evidence used by Elaine Morgan in her many books on the subject. What was not mentioned, and has never to my knowledge been mentioned in respect of this theory, is that it is essentially Lamarckian, which may account for the neo-Darwinian scientific establishment's resistance to it. According to neo-Darwinism, the fact that we, uniquely amongst the apes, have many features that appear to be adaptions to an aquatic life does not mean that our ancestors had one; those features suit us just as well to a terrestrial life. In order for Aquatic Ape Theory to be totally convincing, you need to be a Lamarckist, and believe that most characteristics are the accumulated responses to the environment inhabited. I now quote from my 1996 book, "The Alternative Life".
Without wishing to rewrite "The Descent of Woman", which I can thoroughly recommend if you make allowance for the inaccuracies of dates, I shall now list some of the human features which Elaine Morgan regards as evidence for our aquatic evolution. These are all features which we are not known to share with other primates.
1.Upright posture. No-one is pretending that we went back to the water and spent all our lives swimming about. As land apes, we had gone far too far along the road of a terrestrial life to revert completely to a life afloat. Our heads were kept above water and we would often have stood on the sea floor. This requires an upright stance. However, evidence suggests that we were probably well along the route that leads to an upright stance before we returned to the water.
2.Hairlessness. In water, hair is a positive disadvantage. It has no insulating properties, it gets tangled easily and it can get things caught up in it. When you get out of water, hair retains some of that water between the strands and that draws heat from the body, causing shivering. However, hair on the top of the head protects the head from the sun's rays. Long hair, especially on women, also provides something for babies to cling on to. What's more, women's hair is known to become thicker during pregnancy.
3.Babies hair. Since the environment inside the womb is similar in apes and humans, babies are often born with a pelt of hair over their bodies, just like a baby ape's except that the hair is in a streamlined pattern which resembles the way it would lie if water were flowing over it. This Lamarckist feature could only have come about as a consequence of ancestral habits after birth affecting subsequent development before birth. Babies can be, and often are, born underwater and they show a great affinity with it, suggesting it was normal practice.
4.Fat. Most land mammals distribute their fat cells throughout their bodies. Like other sea mammals, we have subcutaneous fat at the outside of our bodies, which forms an insulating layer.
5.Protuberant breasts. The purpose of flexible, protuberant breasts is to bring the nipple near to the crook of the elbow so that mother and baby can both relax while breast-feeding in the water. They also provide thermal insulation for the milk.
6.Tears. Only salt-water crocodiles, sea mammals and other marine animals are known to cry. For most of them, it is believed to be a mechanism for the elimination of salt, since the tears are very concentrated. We produce salty tears.
7.Hymen. Although not permanent, the hymen does afford some protection for the developing womb from the effects of sea water. It is certainly inconceivable that the hymen evolved as an indicator of virginity.
8.Downward-sloping noses. When you're swimming forwards, it helps if the flow of water doesn't go down your nostrils.
9.Diving reflex. Though not as well developed as in other sea mammals, it appears that we do have a special mechanism which allows us to stay underwater longer than other land mammals. This mechanism slows down the heart rate and makes sure that what oxygen there is gets supplied to the brain.
10.Frowning. This is a natural response to the glare on water.
The most impressive new piece of evidence for our aquatic origins concerns our dependence on Omega-3 fatty acids and iodine for the development of our large, complex brains. These chemicals would not be readily available to a terrestrial ape, but would be abundant in a seafood diet. Furthermore, the same team shows that, as the body sizes of all terrestrial mammals increase (from a mouse to an elephant), their brain to body ratios decrease, whereas the brain to body ratios of sea mammals and humans do not show any significant decrease. Thus, our ancestors must have had diets rich in the vital fatty acids and iodine, as do sea mammals. However, diet is an environmental effect which would need to be cumulative in order to cause any evolutionary change.
Both the anthropologist, Leslie Aiello, who featured in the Radio 4 programme, and the science populariser, Robert Winston, have repeatedly asserted, in books and TV programmes, that the reason our ancestors developed big brains was because their diets became richer; they don't acknowledge (and probably don't realise) that their assertion is flat Lamarckism (unless of course they are claiming our ancestors' brains could have gone from small to big in one generation). Similarly, many prominent evolutionists who are critical of neo-Darwinism for down-playing the role of the environment do not acknowledge that, in order for nurture to have played any direct part in evolution (as opposed to individual development), its effects have to be cumulative, which means that acquired characteristics must be transmitted through generations.
If such transmission happens at all, and modern evidence from epigenetics says it does, then the mechanism exists, so its effect upon evolution could have been enormous. In my opinion it is in the mechanism by which acquired characteristics become transmitted that the key to evolution lies. Rupert Sheldrake's hypothesis, which I support, is that the answer lies in some as-yet-undetectable communication system. The difference between this view and classic Lamarckism is that characteristics are not inherited exclusively from parents but are received, in descending degree, from one's close relatives, one's race, one's species, one's genus and ultimately from the whole of the living world.
Whatever the answer turns out to be, evolution theory is not going to advance until it goes back to the end of the 19th century and re-accepts the transmission of acquired characteristics as an empirical reality that needs to be accommodated. Acceptance of Aquatic Ape Theory is just one of its consequences.