Question
QUESTION 2 Microevolution is defined as a change inallele frequencies in a population over generations. Please explainwhat an allele is, in genetic terms. Name the three major factorsinvolved in allele frequency changes in populations. Describe, indetail, how natural selection works on individuals, while evolutionoccurs in populations. Include a real or hypothetical example ofthe process of natural selection in your answer other thaninsects and insecticide! Identify the specific natural selectionpressure and the specific trait being selected for in yourexample. QUESTION 2 Microevolution is defined as a change inallele frequencies in a population over generations. Please explainwhat an allele is, in genetic terms. Name the three major factorsinvolved in allele frequency changes in populations. Describe, indetail, how natural selection works on individuals, while evolutionoccurs in populations. Include a real or hypothetical example ofthe process of natural selection in your answer other thaninsects and insecticide! Identify the specific natural selectionpressure and the specific trait being selected for in yourexample.
Explanation / Answer
An allele is a particular form of a gene which gives rise to acertain trait. One major factor which impacts allele frequencychanges is genetic drift. Drift is when there is a change in allelefrequency due to random selection. Certain genes may go to fixationor be removed from the population due to the success or failure ofthe carrier(s) to mate as a result only of chance. Another factoris sexual selection. This is when a certain phenotype of a speciesis preferred for mating because of a visible trait. For example, amale peacock has a large tail which it uses to attract females.This tail became standard in the population because the femalespercieved it as a sign of fitness and mated preferentially with thelargest tail peacocks. Finally, allele frequency change can occurdue to directional selection. This is when a certain extremevariant of a trait is best suited to the environment. The membersof a species with this trait will survive and reproduce better andeventually the trait will become the norm. Natural selection acts upon individuals because it actuallyfavors certain specific phenotypes. The population as a whole doesnot have the same phenotype so the individual members with thephenotype best suited to their survival is most likely to surviveand reproduce. Evolution acts on the population as a whole since itis a change in allele frequency within this population over time.As a result of the effects of natural selection, a certainphenotype (caused by a specific allele) may eventually becomethe population norm. As a result, the frequency of that allele willhave increased over time, constituting evolution, but naturalselection will not have acted upon the population. An example of natural selection is antibiotic resistantbacteria. The pressure is the antibiotic which kills the bacteria.Certain bacteria within the population will, by chance, have anallele which confers resistance to this antibiotic. Once exposed tothe antibiotic, these bacteria will not die while the rest of thepopulation will. The antibiotic-resustant trait is selected, andthese bacteria will reproduce. Eventually, a new colony ofantibiotic-resistant bacteria will arise.