Essays on Directional Selection

Module 6: evolution part 1

Describe three ways in which natural selection can affect a population over time

- directional selection - stabilizing selection - Disruptive selection In directional selection, the phenotype is favored over genotype causing allele to move in one direction and hence creating certain traits in an organism. The favored alleles are therefore dominant over the other alleles. For example, in a community that consist of bird with a length of 2cm and grain eater, after a long period and a change of food available the length of beak can change gradually. The dominant allele leads to the required change in the shape ...

Module 6: evolution part 1

Describe three ways in which natural selection can affect a population over time

- directional selection - stabilizing selection - Disruptive selection In directional selection, the phenotype is favored over genotype causing allele to move in one direction and hence creating certain traits in an organism. The favored alleles are therefore dominant over the other alleles. For example, in a community that consist of bird with a length of 2cm and grain eater, after a long period and a change of food available the length of beak can change gradually. The dominant allele leads to the required change in the shape ...

This paper is about the sexual selection. It shows how sexual selection has an enormous effect on the evolutionary changes with different characteristics selected for and against (Brewster and Houde 2003, p. 1057). The common result of this phenomenon is the directional selection. This is where phenotypes indicate high fitness level resulting to an increased number of offspring in this phenotype (Brooks and Endler 2001, p. 1007). By increasing the rate of directional selection and opportunity for the sexual selection methods, the ability of survival and the average fitness will increase. The processes involve dauer processes. Dauer entry is ...