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

Question

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The scenario describes a founder effect, as a small group of Drosophila initiated a new population on a new island. Genetic drift is implied through the small initial population size affecting allele frequencies. Adaptive radiation is evident as the Drosophila diversified into different ecological niches on the new island, driven by environmental and sexual selection pressures.

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