The Role of Geothermal Features in Human Evolution: A Hypothesis

Dr. Medler has been working for years on his hypothesis that hominin evolution may have been influenced when our ancestors began cooking food on thermal features found near volcanism in the African Rift. Harvard professor Richard Wrangham has previously proposed that access to cooked food drove many of the evolutionary adaptations that differentiate modern humans from the other hominins found before Homo erectus approximately two million years ago. These adaptations include, among others, reductions in the size of mouths, teeth, jaw muscles, and digestive tracts. Wrangham also argues that access to the extra nutrition available in cooked food provided the energy required for the sudden 50% expansion of the brain we see with the arrival H. erectus. However, there is little direct evidence that hominins were able to control fire at that time or that fire was a daily agent in the landscape. Medler proposes that during this time, many groups of hominins may have had access to thermal features, such as steam vents or hot springs. Such access could have provided a means of cooking food for evolutionarily significant populations of hominin long before they developed the cognitive abilities necessary to make or control fire. To evaluate the veracity of this hypothesis, Medler and his students have developed maps overlaying hominin archeological sites over the massive lava flows occurring while these steps in our evolution were occurring. These maps demonstrate that many of the hominins were living in close proximity to long term active volcanism and likely had access to thermal features that were capable of cooking food. He has been presenting these ideas in a TEDx talk, at international conferences, and in speaking engagements in the US and Europe.