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Finches: Evolution in Action |
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Medium ground finches have relatively large beaks to crack large cactus seeds. During an El Niño, desert cacti suffer while grasses and wildflowers that produce small seeds thrive. Small seeds become more plentiful than large ones. As a result, the finches with the smallest beaks are at an advantage and produce the most offspring. Within a few generations, the average beak size among the finches becomes smaller. |
Medium ground finch, Geospiza fortis. |
