BLG 144 Chapter Notes - Chapter 26: Meiosis, Wild Type, Synapomorphy
27 Dec 2017
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Fossil records transitional compared to fossils. Inbreeding increases the rate at which purifying selection eliminates recessive deleterious alleles from the population. Benthic sticklebacks have no pelvic spines due to predation by dragonfly larvae which catch them by the spines. If gene flow ends, allele frequencies in isolated population are free to diverge meaning that the population begin to evolve independently of each other. If mutation, selection, and genetic drift cause isolated populations to diverge sufficiently, distinct types, or species, form that is, the process of speciation takes place. *speciation occurs when populations of the same species become genetically isolated by lack of gene flow and then diverge from each other due to selection, genetic drift, or mutation. *populations can be recognized as distinct species if they are reproductively isolated from each other, if they have distinct morphological characteristics, if they exploit different sets of resources, or if they form independent branches on a phylogenetic tree.
