Trait Evolution: From Molecules to Populations
Evolution is often taught only in the context of ecological systems and isolated from genetic and cellular ones. These case studies track the evolution of traits from their origination in DNA mutation.
Phenotypic Evolution
Phenotypic evolution is defined as a change in the frequency of alleles in a population over time that results in a change in the distribution of phenotypic traits in that population. A phenotypic trait is an observable and measurable characteristic possessed by an organism. Although evolution is defined by changes in allele frequencies, the process of natural selection can only act on the phenotypic expression of these alleles. Since the genotype (i.e., the allelic make-up) of an individual partially determines the expression of phenotypic traits, understanding the process of evolution via natural selection requires tracking traits from their origination in DNA mutation, to the production of different proteins, to the fixation of alternate macroscopic phenotypes in reproductively isolated populations. The purpose of our trait evolution cases is to help students learn about the various sub-disciplines of biology in an integrative manner, with an emphasis on evolution as the unifying theme of the life sciences. Below are short abstracts of each phenotypic evolution case along with links to PowerPoint slides, question guides, games and sims, and videos to support each case.