Humans
Modern humans evolved from a lineage of upright-walking apes that has been traced back over 6 Ma to Sahelanthropus. The first known stone tools were made about 2.5 Ma, apparently by Australopithecus garhi, and were found near animal bones that bear scratches made by these tools. The earliest hominines had chimp-sized brains, but there has been a fourfold increase in the last 3 Ma; a statistical analysis suggests that hominine brain sizes depend almost completely on the date of the fossils, while the species to which they are assigned has only slight influence. There is a long-running debate about whether modern humans evolved all over the world simultaneously from existing advanced hominines or are descendants of a single small population in Africa, which then migrated all over the world less than 200,000 years ago and replaced previous hominine species. There is also debate about whether anatomically-modern humans had an intellectual, cultural and technological "Great Leap Forward" under 100,000 years ago and, if so, whether this was due to neurological changes that are not visible in fossils.
Read more about this topic: Evolutionary History Of Life
Famous quotes containing the word humans:
“The worst condition of humans is when they lose knowledge and control of themselves.”
—Michel de Montaigne (1533–1592)
“It is quite a common and vulgar thing among humans to understand, foresee, know and predict the troubles of others. But oh what a rare thing it is to predict, know, foresee and understand one’s own troubles.”
—François Rabelais (1494–1553)
“As humans have a prior right to existence over dogs by virtue of being more highly evolved and having a superior consciousness, so women have a prior right to existence over men. The elimination of any male is, therefore, a righteous and good act, an act highly beneficial to women as well as an act of mercy.”
—Valerie Solanas (b. 1940)