more and more dry status in East Africa half a million years ago led to the local extinction of magnanimous mammals in the region . For former world , the pick were to adapt or die , and our root ’ response helped make us what we are today , initiating a major bounce in the exploitation of tools .
anthropologist mull over the causes of world ’s technological ontogeny have speculated that climate was a potential cause . For example , if the woodland in which our ancestor once dwelled were replaced by Savannah , ourgradualmovement out of the trees would make sense . These ideas have been hard to test however , because we have miss much grounds of past climate in the most relevant places .
Attempts have been made to extrapolate from more remote climate criminal record , butProfessor Bernhart Owenof Hong Kong Baptist University has provide something much better : an indication of condition in the river basin of Lake Magadi , Kenya , close-fitting to sites inhabited at the time .
About 575,000 years ago , Magadi started find less water , and the plant mintage around it became indicative of a dryer mood . The alteration was enormously slow liken to what we are witnessing today , but was still sufficient to cause thedisappearanceof large graze animals from the fogey records at sites nearby . The flaked dick and spearhead identified with theMiddle Stone Ageappeared not long after .
Magadi becomes a table salt cooking pan in the dry time of year , filling with water when the rain get along . Once , however , it remained sozzled all class around , albeit shrink to an uncomfortably salty leftover at times . InProceedings of the National Academy of Sciences , Owen and Colorado - author report that sediment at Magadi ’s base give away the local rain over a period of more than a million years .
The local climatic status can be read in Magadi ’s sediments in several ways . The mixture of table salt and organic materials supply an denotation of how much water enfeeble to the lake from the environ hills . Pollen trapped in the mud reveals the dominant nearby plant species . in conclusion , the mix of plankton living in the lake track the rising brininess over sentence , as species more suitable to fresh waters die out once the region ’s rainfall shrank and evaporation climb .
The resultant line up well with grounds of global temperature variety and climatical shifts elsewhere in Africa . However , confirmation that these fault were being experienced in a place our ancestors lived contribute credibility to hypothesis that meaning innovations , such as advanced tools and the institution of trading web , come in reception to reduce food availability .
Ironically , the slow natural clime change of the era contribute to give humans the content to inflict such rapid clime modification on the earth today .
