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David Sadava H. Craig Heller Gordon H. Orians William K. Purves David M. Hillis Biologia.blu B – Le basi molecolari della vita e dell’evoluzione The Evolution of the Human Species. The Evolution of the Human Species. Who were the first humans? When and where did they live?
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David Sadava H. Craig Heller Gordon H. Orians William K. Purves David M. Hillis Biologia.bluB – Le basi molecolari della vita e dell’evoluzioneThe Evolution of the Human Species
The Evolution of the Human Species • Who were the first humans? • When and where did they live? • What makes us human?
The Evolution of the Human Species - Who were the first humans? Human appearance on Earth
The Evolution of the Human Species - Who were the first humans? Human taxonomy
The Evolution of the Human Species - Who were the first humans? Primate evolutionary trends • Digit mobility (grasping and opposability) • Optical shift • Bipedalims • Relative size of the cerebral cortex • Parental care
The Evolution of the Human Species - Who were the first humans? Close relatives Human species and anthropomorphic apes (gorilla, gibbon, orangutan, chimpanzee) belong to the superfamily of the Hominoidea, primates without tails.
The Evolution of the Human Species - What makes us humans? Hominidae characteristics The face shows a relative degree of prognation The face isstraight The spine meets the skull in the back The spine meets the skull, balancing the head in a vertical position Bipedal gait (man is truly vertical) Quadrupedal gait (knuckle-walking) Short pelvisallowsbipedalism Femoral shaft angle,(feet directly below the center of gravity) Femur almostverticalwithin a horizontalplane Opposability of big toe Non-opposabilityof big toe Plantararch and a more robustcalcaneus Plantararchmissing
The Evolution of the Human Species - Where did the first humans live? A common ancestor Different climates in the two areas of the Eastern African Rift Valley are thought to have caused the evolutionary divergence between Hominidae and anthropomorphic apes.pes Atlantic ocean Indianocean
The Evolution of the Human Species - Who were the first humans? Early hominid characteristics • Bipedalism • Brain size grew larger (genus Homo) • Reduction of sexual dimorphism (Homo erectus)
The Evolution of the Human Species - When did the first humans live? • *ratio of the maximum width of the head multiplied by 100 divided by its maximum length • The first members of the genusHomoappearedaround 2.5 millionyears in Africa.
The Evolution of the Human Species - Who were the first humans? Turkana Boy (Homo erectus) Homo erectus is generally considered to have been the first species to have expanded beyond Africa, and related fossils are spread over two continents. A nearly complete 1.6-million-year-old skeleton, found near Lake Turkana, Kenya, belonged to an eight-year-old boy.
The Evolution of the Human Species - Who were the first humans? Professor Svante Pääbo holding the skull of a Homo neandertaliensis An international consortium of researchers has sequenced the genome of our closest relative, the Neandertal. Results indicate that Neandertals are slightly more closely related to modern humans outside Africa. The team also identified several genomic regions that appear to have played an important role during human evolution. (Science on May 7, 2010)
The Evolution of the Human Species - What makes us humans? Two possible models Out-of-Africa model Multiregional model Europe Africa Asia Europe Africa Asia Interbreeding between people living in Europe, Asia, and Africa (gene flow) (present) Homo sapiens evolved from Homo erectus in Africa 0.5 million years ago Modern humans evolved more or less simultaneously in all major regions of the Old World from local archaic humans. Humans with modern traits left Africa from 50,000 to 60,000 years ago to settle the world (1.8 millionyears ago) 13
The Evolution of the Human Species - What makes us humans? Cultural evolution • Workedstonetools • Evolution of language • Cave art, burials • Domesticanimals • and agriculture 14