Darwin discovered twenty different species of finches in the galapagos islands. he hypothesized that as new islands arose, finches colonized the islands and rapidly changed into new species, depending on what food was available on each new island. the rapid formation of many new species, as in this case, is called a) gradualism. b) speciation. c) adaptive radiation. d) geographic isolation.

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population.b) the separated population is small, and genetic drift occurs.c) the isolated population is exposed to different selection pressures than the ancestral population.d) different mutations begin to distinguish the gene pools of the separated populations.e) gene flow between the two populations is extensive.