These changes were introduced by James Hutton and Charles Lyell as they both proposed theories in favour of evolution. James Hutton’s theory of Actualism proposed that earth’s past can be explained through what is present today (3,6). Such as, through craters and the formation of sink holes (3,6). Charles Lyell’s theory of Uniformitarianism explained the process to the changes affecting earth are uniform (6). For instance, the formation of valleys as streams carved them in one lifetime could not be seen by one (6). Moreover, one could not see the formation of mountains, and other landscapes due to sediment deposits in their lifetime, proved the theory of uniformitarianism (6). The theories suggest that earth has evolved from what it used to be centuries ago, and can be concluded that these are the external factors that have contributed to the environmental changes that affect organisms, and at last forcing them to evolve (3,4,6). These theories relate to evolution because geological factors such as barriers affect reproduction, as well as, cause catastrophic changes in the environment affecting natural selection (2,3,6,7). For instance, the western spotted skunk and the eastern spotted skunk may look very similar, but do not mate, as geographic barriers have caused reproductive isolation between the species causing the two to mate with others in geographic area …show more content…
With advancing technology, scientists have been able to create comparisons between DNA and Cytochrome C, and come to a basic conclusion that species have evolved over time from a common ancestor (3,6,7). For instance, DNA from species reveal that some can differ from each other from just 1 amino acid, to 146 amino acids(7). As one knows DNA is passed from the parents to the off springs, thus one can conclude that DNA contains historical information regarding one’s ancestry, and tells a lot of how life has evolved (6,7). Cytochrome C is a protein that enables one to establish evolutionary relationships, as it’s found amongst all living organisms that require oxygen for survival, and it only varies slightly amongst related species (6,7). For example, chimpanzees and humans are very closely related to each other and it is commonly believed by scientists that both species have evolved from a recent common ancestor, as DNA from both species only differs by 5% (7). Furthermore, since many species vary by a few changes here and there, it can be concluded that the development of these species must also have similarities and have evolved over time (3.6). It has been noted that embryos of certain species develop similarly, also known as comparative development (6,7). For example, during the early stage of development of an embryo, one can find similarities between birds and humans