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===<i>Homo erectus</i> and <i>Homo heidelbergensis</i>===
[[File: homo_tree.jpg|300px|thumbnail|left|Anthropologist Chris Stringer’s Proposed Family Tree of the <i>Homo</i> Genus]]
Before the Neanderthals roamed across Europe and parts of Asia, <i>Homo erectus</i> was the dominant hominin species on Earth. It first appeared in Africa about two million years ago and lived until at least 108,000 years ago. Scholars was once thought that Neanderthals and modern humans directly evolved from <i>Homo erectus</i>, although that hypothesis has been challenged in recent years. Neanderthals and modern humans may be directly descended from <i>Homo erectus</i>, but it may also be that they are just closely related and from collateral branches of the same family tree. <ref> Fergusson, Kennan. “What Was Politics to the Denisovan?” <i>Political Theory</i> 42 (2014) p. 170</ref> The common ancestor of the Neanderthals and modern humans is now believed to have been a sub-species of <i>Homo erectus<i> that many anthropologists now argue was a completely unique species of homo.
As <i>Homo erectus</i> emerged from Africa and spread across Asia and Europe, a subspecies emerged about 600,000 years ago, now known as <i>Homo heidelbergensis</i>, which lived until about 250,000 years ago. <i>Homo heidelbergensis</i> is so named because it was first discovered in a sand quarry near Heidelberg, Germany in 1907. <ref> Klein, Richard G. <i>The Human Career: Human Biological and Cultural Origins.</i> Third Edition. (Chicago: University of Chicago Press, 2009), p. 311</ref>