Genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions. Typically, the surviving population is no longer genetically representative of the original population.
when a few individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool isn't reflective of the source population
evolution by one species to resemble the coloration body shape or behavior of another species that is protected from predators by a venomous stinger bad taste or some other defensive adaptation
a phenotypic intermediate between two parents. polygenic traits controlled by more than one locus. ex: height.