# data[].attributes.headline
Which mechanism of microevolution caused the beak of medium ground finch population in Daphne major to increase from 1976 to 1978?

# data[].attributes.subject
Which mechanism of microevolution caused the beak of medium ground finch population in Daphne major to increase from 1976 to 1978?

# data[].attributes.body
Natural selection caused the beak of the Medium Ground Finch population in Daphne Major to increase in size from 1976 to 1978. The Medium Ground finch birds eat seeds out of portulaca and Tribulus plants. Before the drought, there was an average of 9.7 portulaca seeds per month. During the drought, there was an average of 3.7 seeds. After the drought, there was an average of .36 seeds. The Tribulus plants had an average of 8.8 seeds per month before the drought, 8.3 during the drought, and 4.9 after the drought. The beak depth before the drought 9.65 mm and the average beak length was 10.71 mm. After the drought, the average beak depth was 10.55 mm and the average beak length was 11.61 mm. About 3 years before the drought there was an average of 393 millimeters of rainfall each year. During the drought, there was 20 mm of rainfall. about 3 years after the drought there was an average of 210 mm of rainfall each year. Natural selection occurs when the trait affects the survival and ability to reproduce. To survive the medium ground finches eat Tribulus plants seeds and portulaca plant seeds. when the birds don't have the ability to eat the seeds or the plants don't have seeds for the birds to eat they die. Over time the beaks of the birds have adapted to the way they eat the seeds, so when the beak hasn't adapted as in, not being long enough or not being thin enough they starve and die. The drought caused the seeds to die or be washed away which made it hard and nearly impossible to find food to eat. So when the birds couldn't find any seeds to eat they started to starve and die.