BI111 Lecture Notes - Lecture 6: Systematics, Genetic Drift, Reproductive Isolation
Document Summary
Species are a diagnosable cluster of individuals within which there is a parental pattern of ancestry and decent. Species declinations based on common ancestry(smallest diagnostic monophyletic group) In uni-parental species, little gene flow between different geographic forms might lineage: is each clone with a mutational species? interbreed. If groups can still reproduce, may not remain separate spe(cid:272)ies (cid:271)e(cid:272)ause of ge(cid:374)e flo(cid:449) . Sometimes species arise from repeated events- (polyploids) and are not monophyletic in origin. Species delinations based on subjective judgement of any competent systematist. Pros: decisions bases on careful consideration of all available information, flexible criteria for different taxa. Species are groups of individuals that are reciprocally characterized by features that would have negative effects in other groups and that cannot be regularly exchanged between groups upon contact (cid:862)opposite fit(cid:374)ess effe(cid:272)ts(cid:863) of alter(cid:374)ati(cid:448)e alleles. Differences may be due to differential adaptation, genetic drift, or other non-adaptive processes (including polyploidism or infection by symbionts)
