ANT203H5 Chapter Notes - Chapter 4: Evolutionary Taxonomy, Reproductive Isolation, Chronospecies
Document Summary
Chapter 4 biological species concept: defines species in terms of reproductive capability. It assumes two species either belong or do not belong to same species. suggests change was instantaneous. Ignores variation in a group. phylogenetic tree: a diagram showing the evolutionary relationships between species. As a species changes over time, chronospecies refers to the different recognition of the biological changes that have taken place. Only one species at any point in time. 2)cladogenesis: branching evolution; he formation of one or more new species from another over time. Reproductive isolation: genetic change that can lead to an inability to produce fertile offspring. Speciation: the formation of a new species from a parent species step 1) elimination or reduction of gene flow between population. > gene flow reduces differences between populations , thus keeping all populations in same species. *population must become genetically isolated for speciation to occur. *thus first step is isolation; reduction of gene flow provides the opportunity for speciation.
