In a population of finches, birds with small, thick beaks can efficiently crack the seeds of one species of plant, while birds with long, thin beaks can efficiently crack the seeds of another plant species. Birds with medium-sized beaks cannot efficiently eat either kind of seed. After many generations, the distribution of beak size in these birds will be _______________ because of ___________________.
a) normal; stabilizing selection
b) skewed to the left; directional selection
c) skewed to the right; directional selection
d) normal; environmental pressures
e) "U"-shaped, with peaks at the low and high extremes of beak size; disruptive selection
Ans: e) "U"-shaped, with peaks at the low and high extremes of beak size; disruptive selection
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