1.   The cactus ground finches have long beaks for eating seeds and cactus pulp.

2.   Most female cactus finches starved, and the males mated with some ground finches.

3.   The Grants said that over time the beaks of the cactus finches became blunter, more like those of the ground finches.

4.   This produced healthy hybrids that mated only with cactus finches.

5.   This process put genes from the ground finches into the gene pool of the cactus finches.