Based on your reading of Grant and Grant (2006) excuse the significance of what they observed. Your answer should include a discussion of the evolutionary mechanisms that might be involved. You may not consult with for each one other for your answer. Your work should be your own.
Shanese Snell
BIO 382
14 February 2012
Dr. Byron
While see the Galápagos island of Daphne Major, Peter and B. Rosemary Grant witnessed character shift in the finches of the island. In 1977, they witnessed a drought that depleted the down in the mouth seed population on the island. The loss small seeds caused concentrated mortality in the population of the small ground finches (Geospiza fuliginosa). Thus, directional selection towards the right opted medium ground finches (Geospiza fortis) and giant ground finches (Geospiza magnirostris).
In 1982, the G. magnirostris was introduced to Daphne after El Niño. This presented a problem to G. fortis because thither was a new competitor for food.
The deuce female and three male biggish ground finches began to breed, multiply, and let a competitor of the medium ground finches. G. magnirostris is double the size of G. fortis and can consume 3 seeds for every 1 that G. fortis eats. The large ground finches began to exclude the medium ground finches from feeding areas which by 2004 ended up causing the medium ground finches to favor a smaller beak size. The type of selection seen here is directional selection towards the left for G. fortis. Meanwhile G. magnirostris experienced stabilizing selection.
Lastly, in 2004 another drought had occurred which set the stage for much competition. The finches quickly exhausted the large seed population and in the long run suffered. The large finches and the...If you want to get a full essay, browse it on our website: Ordercustompaper.com
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