Bio 142 exam 2 part 2/5
Monophyletic group
a group including an ancestor and all its descendants
Paraphyletic group
a group including an ancestor but not all descendants
Allopatric Speciation
populations of a species become geographically separated by a physical barrier, which prevents them from interbreeding.
Sympatric Speciation
speciation occurs within a single, continuous population without geographic separation.
What are the mechanisms of geographic isolation
dispersal and vicariance
dispersal
movement of a small group of individuals away from the rest of its population, asymmetric population size at beginning of speciation.
vicariance
the geography moves/ shifts but not the actual population, not asymmetric (dont know the population size)
What we need for speciation to occur
an interbreeding population, geographic subdivision, evolutionary change, reproductive barriers allow coexistence.