How Does Climate Affect Human Evolution

Climate Effects on Human Evolution

This article explores the hypothesis that key human adaptations evolved in response to environmental instability. This idea was developed during research conducted by the Smithsonian’s Human Origins Program. Natural selection was not always a matter of ‘survival of the fittest’ but also survival of those most adaptable to changing surroundings. (Illustrations for this article coming soon.)

Background Paleoanthropologists – scientists who study human evolution – have developed a variety of ideas concerning how environmental conditions may have stimulated long-term human evolutionary change. Human evolution has involved the emergence of a diverse suite of species and an accumulation
Some views assume that certain adaptations, such as upright walking, or tool-making, were associated with specific habitats. These types of hypotheses are referred to as habitat-specific. The best known habitat-specific hypothesis is the savanna hypothesis, which states that many important human adaptations arose on the African savanna or were influenced by the environmental pressure of an expanding dry savanna. According to this idea, upright walking proved to be a beneficial way of moving across an open landscape. Another version of this idea is that upright walking had the additional advantage of freeing the hands, which was advantageous for carrying items and making tools in the African savanna. Other habitat-specific hypotheses consider woodlands or forests or cold habitats as the key to certain
Stone tools conferred significant advantages. The first known stone tools date to around 2.6 million years ago. Simple toolmaking by stone-on-stone fracturing of rock conferred a selective advantage in that these hominin toolmakers possessed sharp flakes for cutting and hammerstone that were useful in pounding and crushing foods. Basic stone tools thus greatly enhanced the functions of teeth in a way that allowed access to an enormous variety of foods. These foods included meat from large animals, which was sliced from carcasses using sharp edges of flakes. Bones were broken open using stones to access the marrow inside. Other tools could be used to grind plants or to sharpen sticks to dig for tubers. Tool use would have made it easier for hominins to obtain food from a variety of different sources. Tool use would have widened the diet of hominins. Meat, in particular, is a food that obtainable in equivalent ways in virtually any type of habitat that early humans may have