query: How long has the species homo sapiens existed?
passage: Homo sapiens
The age of speciation of H. sapiens out of ancestral H. erectus (or an intermediate species such as Homo antecessor) is estimated to have been roughly 350,000 years ago.[2] Sustained archaic admixture is known to have taken place both in Africa and (following the recent Out-Of-Africa expansion) in Eurasia, between about 100,000 and 30,000 years ago.
passage: Middle Stone Age
As early Homo sapiens began to diversify the ecological zones that they inhabited during the MSA, the archaeological record associated with these zones begins to show evidence for regional continuities. These continuities are significant for a number of reasons. The expansion of Homo sapiens into various ecological zones demonstrates an ability to adapt to a variety of environmental contexts including marine environments, savanna grasslands, relatively arid deserts, and forests. This adaptability is reflected in MSA artifacts found in these zones. These artifacts display stylistic variability depending on zone. During the Acheulian, which spanned from 1.5 million years ago to 300 thousand years ago, lithic technology displayed incredible homogeneity throughout all ecological niches. MSA technologies, with their evidence for regional variability and continuity, represent a remarkable advance.[1][7][10] These data have been used to support theories of social and stylistic development throughout the MSA.[27]