Early human migrations

The earliest migrations and expansions of archaic and modern humans across continents are believed to have begun approximately 2 million years ago with the early expansions out of Africa by Homo erectus. This initial migration was followed by other archaic humans including H. heidelbergensis, which lived around 500,000 years ago and was the likely ancestor of Denisovans and Neanderthals as well as modern humans. Early hominids had likely crossed land bridges that have now sunk. Within Africa, Homo sapiens dispersed around the time of its speciation, roughly 300,000 years ago. The recent African origin theory suggests that the anatomically modern humans outside of Africa descend from a population of Homo sapiens migrating from East Africa roughly 70–50,000 years ago and spreading along the southern coast of Asia and to Oceania by about 50,000 years ago. Modern humans spread across Europe about 40,000 years ago. Early Eurasian Homo sapiens fossils have been found in Misliya Cave (Israel), dated to around 194,000–177,000 years old. It has also been claimed by some paleoanthropologists that a skull fragment found in Apidima Cave (Greece), dated to around 210,000 years old, may have belonged to Homo sapiens, although that skull fragment can't be confidently attributed to Homo sapiens. These fossils seem to represent failed dispersal attempts by early Homo sapiens, who may have been replaced by local Neanderthal populations. The migrating modern human populations are known to have interbred with earlier local populations, so that contemporary human populations are descended in small part (below 10% contribution) from regional varieties of archaic humans. After the Last Glacial Maximum, North Eurasian populations migrated to the Americas about 20,000 years ago. Arctic Canada and Greenland were reached by the Paleo-Eskimo expansion around 4,000 years ago. Finally, Polynesia was populated within the past 2,000 years in the last wave of...