Projeto GAP

Curiosities - Information

Hands on the path of evolution

 The most recent news about Ardi – our 4.4 million year old “grandmother” – refers to the hands’ question and, therefore, the bipedalism evolution. The research, in the cover of the Science magazine, had a worldwide reaction for making a creature from 125 fossilized fragments consisting of parts of the skull, jaw with some teeth, fragments of arms, hands, bowls, legs and feet. According to the scientists, the most striking feature of Ardi are the hands, which are not from a monkey, but frighteningly human. Such novelty made us to accept that hands are not unique human, much less modern, because they are very old. According to the anthropologist C. Owen Lovejoy, “it’s likely that the human hands are older than the chimpanzees”.

The Ardi finding change the concept of the “missing link” between men and primates: before, we believed that the link was a more intelligent chimpanzee. However today, it’s known that the link between men and the chimpanzees was more human. Ardi, with human hands and chimpanzee feet, is not the missing link but a member of human lineage.

It’s interesting – even surreal-  that this kind of research created a certain type of hominid from fragmented pieces, but, in practical terms, what this has taught us is exactly what we stand for: the chimpanzees, contrary to what we thought, are much more humans. There are a lot of similarities and kinship between us, the modern humans, and the great primates, primitive human.

The hands of a chimpanzee are very similar to ours – like many other parts of the anatomy and physiology. In the first years, the hands are even more similar, without the calluses arising with the constant support of the phalanges on the ground for locomotion – unlike us, chimpanzees, most of the time, move around supporting their hands on the floor. For example, 5 months old Sofia hands’ are very similar to ours. With time, however, the hands are more and more in use and calluses arise, what is extremely useful, but, on the other hand, it causes the loss of sensibility for movements and of the hands, something that is very important for us – without it, for example, it could be impossible to type a simple text on the computer.

And here enters the bipedalism as one of the fundaments for the primates’ diversification. We, bipeds, have a bigger domain and sensibility of our manual movements. But, it did not come easily. Our posture (which allows us the freedom of the upper body), with a skeleton still in process of adaptation, can develop a back pain because of the way we walk. Everything in life has a price. We decided to pay this price, differently of the other primates which continued their locomotion without forcing their back.

As Ardi makes us rethink about our ancestry, the question is: Are we really the most evolved? Who can guarantee that the bipedalism is, in fact, a valuable characteristic? In the human eyes, the answer seems obvious, but if we looked with eyes of primates, we could be taken by surprise….

MSc. Luiz Fernando Leal Padulla
Biologist