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Africa - Human Evolution

dating hominid remains fossils

It was in the great African rift valley that hominids, or human ancestors, arose. Hominid fossils of the genus Australopithicus dating 3-4 million years ago have been unearthed in Ethiopia and Tanzania. And the remains of a more direct ancestor of man, Homo erectus, who was using fire 500,000 years ago, have been found in Olduvai Gorge in Tanzania as well as in Morocco, Algeria, and Chad.

Paleontologists, who study fossil remains, employ radioisotope dating techniques to determine the age of hominid and other species' fossil remains. This technique measures the decay of short-lived radioactive isotopes like carbon and argon to determine a fossil's age. This is based on the radioscope's atomic half-life, or the time required for half of a sample of a radioisotope to undergo radioactive decay. Dating is typically done on volcanic ash layers and charred wood associated with hominid fossils rather than the fossils themselves, which usually do not contain significant amounts of radioactive isotopes.


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almost 5 years ago

I've got no issues on Africa being the origin of modern humans. My question is, "Why Africa?"

From what I've seen/read, climate change was a major factor in "generating" the hominoids. Why might have Africa been the source rather than the American or Asian continents?

The alternatives seem to have much land area in the same climactic belt as Africa. Has there been any speculation which favored Africa as the source rather than other continents?