Relating early Human evolution to late Miocene - early Pliocene climate change

Abstract: Human evolution has been linked to climate change multiple times in the literature. One of the more well-known theories is the ‘savannah’ theory, which states that walking upright became an advantageous character when climate in Africa changed causing drier environments, changing woodlands to savannahs. Human ancestors could cross open fields more easily when walking upright, therefore it was thought that climate change could be a driving factor in the change to bipedal locomotion. Five hominin species were the basis of the study presented here, showing that change towards bipedal locomotion was a mosaic process with gradual change. A review of the relevant literature shows that the timing of change in fossils to bipedal locomotion and climate change do not coincide in the interval 6-3 Ma, therefore suggesting that climate change did not drive human evolution in this case. Changes towards open landscapes with C4 grass dominance peaked at the Pliocene-Pleistocene boundary (2.6 Ma), while the first hominin species already walked completely bipedally before 3.5 Ma.