On the Hawaiian Islands, Speciation in Drosophila Occurred When a Small

Multiple Choice

On the Hawaiian Islands, speciation in Drosophila occurred when a small group of males and females colonized a new island, where they faced environmental selection pressures. In addition, sexual dimorphism - and therefore, sexual selection - maintained reproductive isolation from other populations on the new island. These populations, although closely related, remained ecologically different. These events are examples of ____.

A) a founder effect only
B) genetic drift only
C) adaptive radiation only
D) a founder effect and genetic drift, but not adaptive radiation
E) a founder effect, genetic drift, and adaptive radiation