BIO/101 – Natural Selection
Natural selection, among other mechanisms of evolution, plays a large role in determining the survival ability of a species and how they evolve. Genetic variation is a component of natural selection, and often the strongest or best suited trait variance for a particular environment will thrive. Differential reproduction is also required in the process of natural selection.
Due to all the thriving of the best suited trait variance, the offspring count will be much higher for some variations of the species than for others. The survivors, who have the best trait variations, will then pass on their good traits through heredity. Eventually the desirable traits will dominate the population, if the process continues.
Genetic variation is required for the process of natural selection to work, without it genes could not be altered and therefore no form of evolution could take place. According to “Natural Selection” (2012), “If you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome. It is as simple as that.”
Mechanisms of evolution, other than natural selection; include mutation, migration, and genetic drift. Mutation occurs when there is a change in the DNA, which is the genetic material that offspring inherits from the parents.
Not all mutations are involved in the evolution process. Somatic mutations occur in non-reproductive cells, which are not passed on to future generations. “Natural Selection” (2012), “For example, the golden color on half of this Red Delicious apple was caused by a somatic mutation.
The seeds of this apple do not carry the mutation.” Migration involves the introduction of a new gene into a population, which results in the increase in that gene. Migration is also known as gene flow. When genes are introduced into an environment where they have never previously existed, the benefit to the genetic variation to that population is better (“Natural Selection”, 2012).
Genetic drift is when genes of a certain kind benefit from random events. These species are not necessarily the strongest or best adapted, but they pass on more genes to the next generation.
Biodiversity is crucial to the survival of different species and how well the process of natural selection can work. If there is much biodiversity in a given population, if the population faces an environmental change, it can better adapt and survive the new conditions.
When biodiversity is low, natural selection does not have as many variations that could be better suited to survive and thrive in the new conditions. Adversely, natural selection can have a negative impact on biodiversity.
When the weaker species are rooted out, there are fewer genes in the population which results in a limited biodiversity (Robin, 2010). Biodiversity is important to continued evolution mainly due to the genetic variation requirement of evolution. When a population has a limited biodiversity, it has a low volume of genetic variations.
When a population with low biodiversity gets confronted with a change in environmental conditions, extinction can be rampant. So, greater biodiversity results in the best possible conditions for evolution to occur and the survival of the species.
There are several reasons for mutations to occur in the evolutionary process. A naturally occurring mutation that takes place is when the DNA fails to make an accurate copy of itself during cellular division. When the cell divides, the not so perfect copy, even with very slight differences is a mutation.
Mutations can occur when a cell is damaged by external influences, maybe something toxic for example, and does not accurately repair itself. The repaired cell will ultimately be different, even ever so slightly, from the original cell. This is important, since mutations introduce new genetic variations that can help the evolution process.
According to “Natural Selection” (2012), “Mutations can be beneficial, neutral, or harmful for the organism, but mutations do not “try” to supply what the organism “needs.” In this respect, mutations are random — whether a particular mutation happens or not is unrelated to how useful that mutation would be.”
Sexual recombination is also known as genetic recombination and is a vital source of genetic variation. When sexual reproduction occurs, new combinations of genes are created using the parent’s genes. This shuffling of DNA also helps create a population with good biodiversity.
According to “Genetic Recombination” (2012), genetic recombination is “The process of forming new allelic combination in offspring by exchanges between genetic materials (as exchange of DNA sequences between DNA molecules).” When you combine mutations with sexual recombination, the different combinations of genetic variation are vast (Natural selection, 2010).
Natural selection. (2012). Retrieved from AP Biology Prep Plus 2018-2019: 2 Practice Tests + Study Plans + Targeted Review & Practice + Online (Kaplan Test Prep)
Robin, L. (2010). Biodiversity and Natural Selection: The Human Factor. Retrieved from AP Biology Prep Plus 2018-2019: 2 Practice Tests + Study Plans + Targeted Review & Practice + Online (Kaplan Test Prep) by Kaplan Publishing
Genetic recombination. (2012). Retrieved from Genetics of Populations by Jones & Bartlett Learning
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