Homo erectus was the first member of the genus Homo believed to be a direct ancestor of modern humans (H. sapiens). H. erectus first appeared in Africa more than two million years ago. By 600,000 years ago H. erectus had evolved into H. heidelbergensis, possibly in Ethiopia, and around 400,000 years ago some H. heidelbergensis moved out of Africa and split into two groups, one moving into the Middle East and Europe, where they evolved into H. neanderthalensis, and the other into Asia, where they evolved into Denisovan people. The H. heidelbergensis remaining in Africa evolved into H. sapiens about 200,000 years ago, and descendants of these modern humans later spread throughout the world. This standard account has been challenged by an alternative narrative, in which modern humans evolved from H. erectus populations in the Middle East with several transitional forms appearing in Asia.