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Wednesday, February 13, 2008

How long has man been walking the Earth?

Ever since the philosopher and naturalists, Charles Darwin, and his contemporaries including Wallace, suggested that man had evolved from apes, there has been a continuous, and almost frantic quest for evidence of our ancestors. Of course, where we come from has always been a fascinating question, but it is only comparatively recently that systematic searches have been made for traces of ancient men by such eminent scientists as L.S.B. Leakey and still more recently by his son, Richard. As you might imagine, the idea that man came from monkeys brought with it a great deal of public outcry, and in fact, modern research has shown that man did not descend directly from apes but that the apes and man evolved from a common ancestor.

As you know the first thing that monkeys, apes and man have in common is that they all have backbones, so that they all vertebrates. Many characteristics in man have arisen from living in trees. We share them with other primates, as monkeys, apes and man is known. If you suddenly found that you has to live in a tree, what do you think the most use-full adaptations would be? There would bot be much point in having hoofs like a horse which help the horse to run fast. You would need to be able to hold on to the branches, however, as our hands are well able to do. If you wanted to jump from branch to branch, you would have to be able to judge distances. You would need stereoscopic vision, that is, two eyes positioned at the front of your head, not at the sides as in a fish. You are unable to smell the traces of scent that a dog can, but you do have a much enlarged brain. It is the growth of the brain that has enabled man to leave the comparative safety of the trees and compete with the other ground-dwelling animals that are stronger, have better hearing and sense of smell, can run faster and have warm coats to protect them from the extremes of climate.

As you might expect, because man and apes have developed from a common ancestor, it is not easy to tell when the remains of the primates that have found are of men-like apes or ape-like men. But between ten and fifteen million years ago a creature which has been called a Ramapithe-cus lived in parts of Africa, Asia, and Europe. This may have been the ancestor of man and the other apes, though recent evidence suggests that out ancestor was another creature, the ancestor of the orangutan. However, the groups became increasingly diverse until the first creature that could be called human arrived. This was around four million years ago.


How "Ida" named new fossil help the study about human origins?