BIOL150 Lecture : Biol150 - Speciation.pdf
11 Dec 2013
School
Department
Course
Professor
Document Summary
Gene flow reduced causing divergence to two species. Divergence caused by migration, natural selection, genetic drift. One species results in multiple species exploiting diff parts of the environment (gradient of species) More than one distinct form of phenotype in a population. Can cause speciation if has effect on reproduction. Change in traits (morphology, behavior, timing) due to natural selection. Geographic separation of population with no movement in between. They can be too genetically distinct that they cannot breed - reinforcement. Occurs a lot in plants (70%), b/c reproduce asexually. Due to spontaneous doubling after fertilization, union of unreduced gametes. Mate with other polypoids of same chromosome number. Trade-offs --> benefit for one things creates cost for something else. Natural selection can only occur if the favourable gene exists. Beneficial gene can be on same chromosome as deleterious gene. Ability of genotype to give rise to different phenotypes under different environmental conditions.
