Human Evolution

Humans did not evolve from Apes You Cuz Dad Mum Aunt Uncle Humans did not evolve from Apes You are descended from your mother and father You are related to your aunt and cousin

Common ancestor Where we came from

Apparently human evolution is just like that of other groups We have followed an uncertain evolutionary path As new species evolved, they filled ecologic niches and either gave rise to descendants better adapted to the changing environment or became extinct Our own evolutionary history has many dead-end side branches

Phenotypic differences between humans and other apes Carroll (2003) Nature 422, 849-857

Chimpanzee-human divergence 6-8 million years Hominids or hominins Chimpanzees Humans

Origins of hominids Sahelanthropus tchadensis Chad (Central Africa) Dated to 6 – 7 million years ago Posture uncertain, but slightly later hominids were bipedal ‘Toumai’, Chad, 6-7 MYA Brunet et al. (2002) Nature 418, 145-151

Hominid fossil summary Found only in Africa Found both in Africa and outside, or only outside Africa

Why did bipedalism become the primary adaptation of hominids? Carrying behavior Reduction of overall heat stress - facilitates heat loss through convection by exposing body to air currents, only humans have sweat glands that produce moisture to cool body Most energy efficient way to travel long distances Allows for better vision in open environments & defensive action against predators by freeing hands to throw objects

Origins of the genus Homo Homo erectus/ergaster ~1.9 million years ago in Africa Use of stone tools H. erectus in Java ~1.8 million years ago Nariokatome boy, Kenya, ~1.6 MYA

Additional migrations out of Africa First known Europeans date to ~800 KYA (thousand years ago) Ascribed to H. heidelbergensis Atapueca 5, Spain, ~300 KYA

Origins of modern humans (1) Anatomically modern humans in Africa ~130 KYA In Israel by ~90 KYA Not enormously successful Omo I, Ethiopia, ~130 KYA

Origins of modern humans (2) Modern human behaviour starts to develop in Africa after ~80 KYA By ~50 KYA, features such as complex tools and long-distance trading are established in Africa The first art? Inscribed ochre, South Africa, ~77 KYA

Expansions of fully modern humans Two expansions: Middle Stone Age technology in Australia ~50 KYA Upper Palaeolithic technology in Israel ~47 KYA Lake Mungo 3, Australia, ~40 KYA

Routes of migration? archaeological evidence Upper Paleolithic ~130 KYA Middle Stone Age