What Is Genetic Drift Essay

Change is constant. In order to succeed, it is essential to understand how to adapt to change. As Charles Darwin once said, “It is not the strongest or the most intelligent who will survive, but those who can best manage change.” Evolution is a theory proposed by Charles Darwin that explains how species change and adapt to their environments. Even though this theory has not be definitively proven, it is strongly supported by countless pieces of evidence from natural selection, genetic drift and phylogeny. In 1859, Charles Darwin published The Origin of Species, in which he proposed his theory of evolution and natural selection. Darwin proposed that natural selection, the process in which individuals who have traits that make them successful …show more content…
Genetic drift is the term used to describe changes in a small population not due to natural selection, but rather, chance. The probability of a certain individual to receive a certain trait is not completely set in stone. It is random, a by-product of the cross-over and independent assortment in meiosis. In a small population, the genetic composition is hard to predict because there are so few individuals. 80% of individuals might have a recessive trait, which is usually not probable. However, as the population gets larger, the gene pool diversifies and the actual genetic composition of the population becomes closer to the predicted genetic composition of the population. Within genetic drift, there are two principle effects. The bottleneck effect occurs when a large majority of a population dies before passing on their genetic information due to a catastrophic event. This effect minimizes the amount of genetic diversity and limits the gene pool. The survivors are then forced to reproduce within a small gene pool, restricting the genetic diversity and changing the genetic makeup of the population. Comparatively, the founder effect occurs when few individuals have a large number of offspring that inherit their genetic traits in large frequencies. The individual that passes on their genetic traits in large frequencies essentially becomes the “founder” of the genetic trait within the population. An …show more content…
Genetic variation contributes to the diversity of genes in a population. The Hardy-Weinberg Principle is a method for geneticists to study genetic variation and evolution. It is a model that predicts the outcome and offspring of a non-evolving population. This model is then compared to an existing population and the differences between the non-evolving population and the existing population display evolution. An example is polyploidy. In animals, polyploidy is extremely rare, however, in plants, polyploidy is common and it is the source of genetic variation. Normally, in a non-evolving population of plant hybrids, the plants would not be fertile and would not reproduce. However, through evolution, plants developed polyploidy to allow for fertility. Genetic variation is caused by meiosis, gene flow, and mutations. Mutations are changes to DNA code that can result in beneficial, neutral, or harmful effects. These effects vary depending on the environment. For instance, a mutation on the hemoglobin gene can be harmful to organisms living at high altitudes but may not cause a big effect on organisms that live at sea level. Positive mutations allow organisms to survive, a result of natural selection. On the other hand, harmful mutations often lead to diseases such as sickle cell anemia. However, negative mutations can on occasion be beneficial. For example, the sickle cell