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Darwin's Theory Of Natural Selection

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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 …show more content…

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 …show more content…

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.

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In the exhibit for The Humans Outside of Africa, there were different skull fossils that were studied and categorized as potentially male or female. However, it is also notable that there were fossils (D2700 and D2735) that were examined to be that of an adolescent. Therefore, this provides paleoanthropologists with a basis for studying the Dmanisi hominids on a generational basis, from adolescent to old

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Mutations deals with the production of DNA cells based on a natural selection by chance. Genetic Drift is solely based on changes and has nothing to do with natural selection. Non-Random mating deals with that populations that chooses their mates based of their

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First, we measured the skull of the Australopithecus using a caliper. We measured the cranium length, width and height and received different measurements. We used the measurements we found and estimated the brain size by using the formula given: 10^(2.53*log(Orbit Height)-2.29)= Body Mass. After plugging in the measurements, we found that the body mass of an Australopithecus is about 41 kilograms. From this, we can estimate that the brain size of this species is not large because their body mass is not large.

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While it is clear that with evolution came about more sophisticated and complex behavior due to the increase in brain use and size, when you compare hominid brains to modern human brains, modern human brains, by far, possess the largest and most complex brains, which is self-explanatory given the fact that while hominids were intelligent creatures, modern humans are far more advanced in their intelligence and capabilities. This brain size

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Donald Johnson had discovered an Australopithecus afarensis in Ethiopia during the year of 1974. Later to be named Lucy, this ape ended up being the, oldest potential ancestor for the hominid species, according to BBC. According to PBS, before her discovery, scientists had rationalized that the main trait that separated humans from apes was intelligence. This was based on the cranial capacity of the skull. Perhaps Lucy developed human-like features to hunt for food or possibly even to look over tall grass.

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Although they walked like humans they were not as developed as humans today. They were short, had small heads, and brains that are one-third the size of a human’s brain today. The offspring grew quickly and reached adulthood earlier than today’s humans.

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Modern humans have evolved over millions of years from primates and therefore we share many special characteristics but as many anthropologists believe, there are many identifiable characteristics which distinguish modern humans from non-human primates. These constraints are both anatomical and behavioural. Biological features include larger brains, smaller frontal teeth, smaller faces and bipedalism (Mann 1972). Bipedalism is a form of terrestrial locomotion which gives the ability of species to walk completely on two legs which Homo Sapiens, known as modern humans, have the ability to do. This gave many special definitive features and traits to humans which have led to many advantages that we now contain today.

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Small teeth in australopithecines revealed that their diet was based on C4 plants, such as grass and sedges (Eadie, 2015, 10/07/2015). This reinforced the idea that our ancestors, the australopithecines, spent more time on ground because they ate things from the plain rather than from the forest (Eadie, 2015, 10/07/2015). Even though such traits of australopithecines suggested they spent more time in the plane they also spent time sleeping on the trees for their safety (Eadie, 2015, 10/07/2015). The skeleton of australopithecines informs us a lot about their social structure. For example, their small canines indicate that they no longer needed to fight as much for mates or to protect or get territory (Eadie, 2015, 10/07/2015).

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So, the genetic diversity or the variety of different genotypes will be severely reduced in modified communities. Also, the ability to survive directly depends on genetic diversity because populations without it will not be able to meet the demands of the environment (Wolfe, Christian). A disease that could be survived by a population with the normal human genetic diversity, would wipe out the modified community without the genetic diversity. Changing the genotype of just one can affect the whole diversity of humans and with the many processes, including sterilization and genetic screening, changing the genotype of one comes with ease. The ease of changing one leaves humans at a point where the achieved diversity can be easily destroyed, further placing them at risk through the threat of disease (Wolfe, Christian).

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Pierre-Paul Grasse says in Evolution of Living Organisms “No matter how complex they may be, mutations do not produce any kind of evolution.” Variation within a species may happen, but they are always still the same species. Dogs produce dogs, cats produce cats, fish produce fish and humans produce

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This means that if genes were to affect the differences in all of these traits, they could also react to changes in natural selection. So we humans could still be evolving, because of all the genetic differences in the population, putting aside medicine and all advancements. Also, like the Rambam Maimonides Medical Journal says, “...human cultural evolution did not stop human populations from adapting to infectious diseases but rather most likely intensified human adaptive evolution to infectious

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Charles Darwin became famous for his theory of natural selection. This theory suggests that a change in heritability traits takes place in a population over time. This is due to random mutations that occur in the genome of an individual organism, and offspring can inherit these mutations. This was defined as the key to evolution, this is because random mutations arise in the genome of an individual. Until the 19th century, the prevailing view in western societies was that differences between individuals of species were uninteresting departures from their platonic ideals of created kinds.

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