The development of stone tools was a crucial aspect of cultural evolution which led to humans existing as they do today. The poster below shows how stone tools were improved by early hominin species over time (from Oldowan tools to upper paleolithic tools) through greater forethought and more complex methods, and how these developments in stone tool production benefited early hominin populations.
Upon testing the Mitochondrial DNA of 147 participants from around the world in 1987, scientific authors Rebecca Louise Cann, Mark Stoneking and Allan Charles Wilson came to the conclusion that all modern Homo Sapiens shared a common female ancestor - nicknamed 'Mitochondrial Eve'. They placed this early Homo Sapien ancestor as having lived in an African population between 100,000 to 200,000 years ago. Mitochondrial DNA is a form of DNA completely separate from nuclear DNA in chromosomes, and is found in eggs rather than sperm cells - this meaning it is passed down through matrilineage. This also means that Mitochondrial DNA is not involved in recombination, and remains predominantly unchanged as it is passed down from mother to daughter unless affected by mutation or undergoes change in a small but growing population. From the separation, purification and analysis of these DNA samples, and the studying of mutation patterns in participants dependent on their location in the world, these three authors inferred that not only was genetic variation more prominent within populations than between populations, but also that each non-African population has multiple Mitochondrial DNA lineages which diverge from one common Mitochondrial DNA gene pool originating in Africa (this supporting the 'Out of Africa' Model of hominin evolution).
