BILD 3 Lecture Notes - Lecture 7: Frequency-Dependent Selection, Allele Frequency, Heterozygote Advantage
17 Mar 2018
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Aa: certain types of selection can maintain allelic variation in populations, heterozygote advantage (sickle cell protecting from malaria) Frequency dependent selection (cichlid fish right or left mouths: neutral variation is not acted upon by selection. Change in amino acids may not alter protein function. Lacewing mating songs: mating occurs when male sings, and female joins. Species are defined by morphological traits alone: used by paleontologists to define fossils, used by other when reproductive biology or phylogeny not available, problems, cryptic species: species that are morphologically identical but genetically distinct (two lacewing species) Fossils: can"t tell between phenotypic variation or different species: different species may represent differences in developmental stage: 3 pachycephalosaurus fossils in different stages of life were once considered 3 separate species: phylogenetic species concept. In a different environment from all the other jumping mice, evolutionarily diverged from rest of the species due to no gene flow. Indistinguishable morphologically but genetically distinct from other subspecies.
