WEIT Chap8

What about us? Chap 8

Darwin firmly believed that humans evolved from other species, apelike creatures, in Africa.This statement created a lot of religious objections.It took fossils to finally convince the skeptics that humans had indeed evolved. He was the first to discover an Australopithecus africanus. The chapter talks about darwin's theory, it explains us his theory and the proofs that he found. It will talk about fossil ancestors, our genetic Heritgae, the sticky question of race and what about now. We will describ all the chapters briefely.

make a short intro [[U tilisateur:Pierre.brawand|Pierre.brawand]] 19 avril 2011 à 22:47 (CEST)

Fossil Ancestors

Complete fossil sequences don't exist. What we must look for is the general trend of the fossils over time, which clearly shows a change from apelike to humanlike features. The older possible hominin discovered is the "Sahelanthropus tchadensis", from the Central African desert of Chad, the region known as the Sahel. It dates from between six and seven million years ago, right when molecular evidence tells us that our lineage diverged from that of chimps. The discovery of this specie suggests that bipedal walking was one of the first evolutionary innovations to distinguish us from other apes. After "Sachelanthropus" we have the six-million-years-old fragments from a species, called "Orrorin tugenensis", which has a single leg bone that is an evidence of bipedality. Then, there's a two-million-years gap with no substantive hominin fossils. That is where crucial information about when be began to walk upright has still to be found. The fossils reappear, beginning about four million years ago and from them we see branches beginning to grow from the hominin tree.

les filles, il faut qu'on se voit pour une sorte de répartition des taches non?

The Sticky Question of Race

There exists visible differences in human types but many biologists stay as far away from this statement because of racial prejudice. Scientists argued the fact that human races have no link with biology and are more a sociopolitical status. For them, a race is a population of a species that is geographically separated and differ geneteically in several traits.

What about now?

Natural selection doesn't have produced differences between races, although we can notice some differences between population within ethnic groups. one example of natural selection is the tolerance of milk. Our ancestor had no source of milk after weaning so that's why

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