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My great-great-great-grandfather refers a number of times to books by Elaine Morgan and especially to one book entitled The Scars of Evolution, where she explores the problems with the male Savannah theory. She takes up how three crustal blocks converged causing a focus on Afar (part of Ethiopa), where many new discoveries were made in the last hundred years.
About 7 million years ago a marine basin was probably formed in this area where the sea flooded in, but never out again. Much of this happened around the time when it is thought that the ape/homo split occurred. One possibility is that the Afar triangle with its volcanoes and desert was mostly a large lake and that some Australopithecus were marooned in the area, perhaps on a large island after a volcano eruption. Perhaps here, females discovered that they could obtain food in the water, while avoiding many land predators. (Alternately they may have been along the shore of the Indian ocean and found that meter deep water there protected them from predators.) That present day Homo Sapiens cry with salt tears, lends some credence to the idea that much of their evolution was in salt water. The large lake formed in the Afar triangle was certainly extremely salty as the area is now extremely salty and dry. Salt deposits are a thousand meters deep and salt is the only export of the area. In the water, moving on four legs, especially while holding an infant, was obviously not possible unless the water was very shallow. Therefore, those animals most proficient at moving on their two hind legs, were most likely to survive, partially because they could be in deeper water and further from land predators. It can be seen today now that members of the monkey family do walk on their hind legs in the water, but not otherwise. Learning to walk upright on two legs would have been a difficult and costly project. Muscular-skeletal, hormonal and circulatory changes had to occur. All these changes would be difficult and take a long time to evolve. Such necessary changes would be easier in the water. In addition at the same time, walking upright in water brings the immediate advantage of being able to breathe easier. In addition, those creatures that had less fur would also have an advantage, since they could move more quickly without wet fur slowing them down. Thus, during a few hundred thousand or perhaps a million years, a bipedal homo with very little fur evolved. It may be that those with hair on their heads that their young could hold onto were more likely to have young that survived. That Homos evolved with good control over their breathing, which is important in water, may have been an important factor in the evolutions of our human voice and language. Apparenty Elain Morgan wrote a fair bit on this in the book The Scars of Evolution. Humans also have a layer of fat bonded to their skin as is very common among aquatic animals, but not so among non-aquatic. This is a major difference when compared, for example, to a chimpanzee. It is quite probable that it was during this time that brain size grew in conjunction with the lengthening of the time that young were dependent upon their mother. In other words, the embryo could not remain in its mother long enough to more fully develop, partially because the brain and its growth demands such huge amounts of energy, and partially because the larger the head and the more developed the rest of the body, the more difficult it would be for the mother to carry the weight of the embryo and therefore she ejected her baby as soon as possible. The extra weight was of course easier to handle if in water a large part of the time. In addition, the water-bound females, could have learned that they could get more food by cracking open shells using rocks, thus creating the first tools (as opposed to men on the plains learning to use stones to crack open bones to get at marrow.) Women probably also learned that they could use the shells of some creatures to scratch more food out of other shells. The sharp edges of some shells could also be used to cut up some of the food into smaller pieces for their infants and eventually females may well have invented the first rudimentary knives. |