Earliest species of the genus Homo; erectus dispersal; Middle Pleistocene hominins; Neandertals; Denisovans; Homo floresiensis; DNA evidence for admixture of contemporary groups; origins models: out of Africa and multiregional; human behavioral modernity; stone tool technologies and art in the archaeological record; Ice Ages and adaptation; settling of the Americas, Australia, and Polynesia based on biological, linguistic, and archaeological evidence