Mechanisms Of Evolution: Genetic Drift And Natural Selection

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The mechanisms of evolution are mutation, gene flow, genetic drift and natural selection. These mechanisms are based upon the changes that occur within an organism’s gene pool and how they affect those organisms and their survivability. Some of these mechanisms of evolution move quickly and affect large populations while others are slow moving and affect small populations. Not all of the evolutionary mechanisms are positive and benefit the population’s long term survival. Commonly these negative effects wipe out smaller populations that tend to be more isolated that large populations which have more genes to stave off the effects. The first mechanism of evolution to look at is mutations which are random changes that take place in DNA patterns. …show more content…
Genetic drift allows for change over time rather than being as sudden as gene flow. Genetic drift occurring over generations usually causes it to only affect smaller populations than that of gene flow. This can be due to the changes occurring within a specific population that are reacting to specific environmental factors they are facing. The slow moving genetic drift can negatively affect a population of organisms when their populations are low and perhaps the introduction of genes from outside would hasten their recovery but is unable to occur. The slow moving genetic drift can create what is referred to as a generic bottleneck where a population is far from another and cannot readily have new alleles introduced. This hastens the possibility of extinction for that population by limiting their ability to adapt to changes in the environment. The book provides the example of the Florida panther which was isolated and populations began to dwindle. Upon scientific investigation it was discovered that the male population of Florida panthers had misshapen sperm which did not offer a high rate of fertilization. Through the use of breeding programs they were able to largely correct the population’s effects from genetic drift. Some of these changes occur due to the habitat shifting on populations and it no longer being …show more content…
By weeding out the weak or non-beneficial genes from the pool, large populations can quickly shift over short generational spans to press the most advantageous survival genetics into prevalence. There are three types of natural selection that occur in nature: directional selections, stabilizing selection and disruptive selection. Directional selections is directly tied to traits that affect physical characteristics such as size, color and pattern. These changes often occur quickly because they are directly responsible for survival of the population. Stabilizing selection occurs because certain traits have a higher survival chance such as the size of the organism effecting its ability to nourish itself and it’s young in a certain environment. These stabilizing traits give the individual a distinct advantage over their own population for survival. The final type of natural selection is disruptive selection which breaks away from the norm again and often benefits the individual quickly against its

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