THE ORIGIN OF MODERN MAN
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Multiregional hypothesis what are the claims behind this
Homo sapiens evolved from the local population of H. erectus in parallel of a number of places including Africa, Europe, Asia and possibly Australia Genetic similarity of all modern people is the product of occasional interbreeding between neighbouring populations Much regional genetic diversity has arisen due to regional selective pressures about 1 million years ago Give subspecies names to regional hominids – Homo sapien neanderthalensis Continuous gene flow prevents new species Last common ancestor in Africa about 1.5 million years ago
“Out of Africa” hypothesis (replacement hypothesis)
all modern Homo sapiens evolved from Homo erectus in Africa replaced all regional populations of Homo from first hominid migration of H. erectus about 1.5 million years ago give separate species names to regional hominids – Homo neanderthalensis Homo sapiens replaced all other regional descendents of Homo erectus Regional genetic differences evolved 80 000 to 100 000 years ago
Third Hypothesis
Homo sapiens dispersing from Africa 100 000 years ago interbred with regional descendants of earlier H. erectus Genomes of indigenous people around globe should reflect a complex mix of ancestries
Genetic Data: Supports Replacement Hypothesis
• comparing mitochondrial DNA: multiregional hypothesis states that modern European mtDNA should be more similar to Neanderthal mtDNA – was NOT. • comparing Y chromosomes: no crossing over so only changes are through mutations which can be used to date differences and trace ancestry and relationships • fossils: fossils in Europe shows total replacement of Neanderthals about 40 000 ya by Cro-Magnon (transition fossils show no interbreeding) fossils outside Europe in Asia might be intermediate between H. erectus and modern Asians
Third Hypothesis
Homo sapiens dispersing from Africa 100 000 years ago interbred with regional descendants of earlier H. erectus Genomes of indigenous people around globe should reflect a complex mix of ancestries
Genetic data supporting replacement hypothesis what was false about the multiregional hypothesis what did we discovering comparing Y chromosomes? what do fossils show and what do they refute/ prove wrong
the multiregional hypothesis states that modern European mtDNA(mitochondrial DNA) should be more similar to Neanderthal mtDNA (*false) • comparing Y chromosomes: no crossing over so only changes are through mutations which can be used to trace ancestry and relationships • fossils: fossils in Europe shows total replacement of Neanderthals about 40 000 years ago by Cro-Magnon fossils show no interbreeding fossils outside Europe