Darwin's Theory Of Natural Selection

The key principle in natural selection is that a species may be born with a different characteristic to the norm. This characteristic may help the organism to survive better in its environment (Scupin and DeCorse, 2015: 49). This results in nature selecting the most fit organism. Many people helped and supported Darwin in his discovery of natural selection. The most infamous scientist being Alfred Russel Wallace. Wallace did research on animals and plants in the Amazon and Southeast Asia (Scupin and DeCorse, 2015: 49). This was then combined with Thomas Maltus’ research to improve their theory (Scupin and DeCorse, 2015: 49). Darwin’s theory was challenged by many people especially those of strong religious beliefs. Many people felt that it

Mutations are the only way in which new genetic material can be introduced into a population as well as it being, “… the primary force behind evolution…” (Scupin and DeCorse, 2015: 56). If a mutation is not beneficial but rather harmful then the it will be removed e.g. cancer cells result in chemotherapy or the individual will die. The second form of human variation is gene flow. “Gene flow is the exchange of alleles between populations as a result of interbreeding” (Scupin and DeCorse, 2015: 57). In gene flow, reproduction introduced new genes into the population. It is also a way in which variation is controlled so that a new species of humans does not evolve. This way mutations are passed from one population to another, most commonly through migration (Scupin and DeCorse, 2015: 57). The third type is genetic drift. This is where sampling phenomena remove or sustain specific alleles in a gene pool. The biggest influence here are chance events. Many different combinations of genetics can be produced but because humans only produce a small amount of offspring, these combinations are limited. A well-known genetic drift is the founder

afarensis and A. africanus. They are classified a hominid as they share many characteristics with primates. The upper body of an A. afarensis hominid is structured for climbing indicting a close relationship to apelike features. The lower body however is more closely related to modern man as it indicates bipedalism. This is indicated through the orientation of lower limb bones and pelvic orientation (Scupin and DeCorse, 2015: 101). The brain size of A. afarensis is also considerably small, 400cc (Scupin and DeCorse, 2015: 98). Another signature characteristic would be the teeth of A. afarensis. They were known to be canine like. Examples of these hominids found would be Lucy who was found in Ethiopia along with the Dikka baby (Scupin and DeCorse, 2015: 101). A. africanus was discovered in southern Africa. They lived after A. afarensis (Scupin and DeCorse, 2015: 102). The average brain capacity was around 450cc (Scupin and DeCorse, 2015: 102). Other characteristics were common with those of A.