UC Berkeley
Image Caption
So we meet again: When another storm reintroduces the island flies to the mainland, they will not readily mate with the mainland flies since they've evolved different courtship behaviors. The few that do mate with the mainland flies, produce inviable eggs because of other genetic differences between the two populations. The lineage has split now that genes cannot flow between the populations.
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This image is part of a series:
Speciation example (1 of 5)
The branching points on this partial Drosophila phylogeny represent speciation events that happened in the past.
Speciation example (2 of 5)
The scene: a population of wild fruit flies is minding its own business on several bunches of rotting bananas, cheerfully laying their eggs in the mushy fruit.
Speciation example (3 of 5)
Disaster strikes: A hurricane washes the bananas and the immature fruit flies they contain out to sea. The banana bunch washes up on an island off the coast of the…