EvidenceFinch Data (Google Sheet) - click hereBand refers to an individual's identity; more specifically, the number on a metal leg band it was given. Show
Mean (average) beak depth of medium ground finches on Daphne Major from 1976 to 1985.
What was the average beak size in 1976?The average beak depth of the population seems to be around 9.6-9.7 mm in 1976, while it appears to be just slightly over 10mm in 1978.
What causes the change in Bill depth between 1976 and 1978?1: Finches of Daphne Major: A drought on the Galápagos island of Daphne Major in 1977 reduced the number of small seeds available to finches, causing many of the small-beaked finches to die. This caused an increase in the finches' average beak size between 1976 and 1978.
Why did the average finch beak depth change from 76 78?Why do you think the average beak depth of the birds increased? Because the drought reduced the number of seeds and finches with bigger beaks were able to eat the larger and harder seeds so more of them survived.
What was the average beak depth in 1978?The 1978 population of the medium ground finch population on Daphne Major had an average beak depth of 10.55 mm and an average beak length of 11.61 mm, which was almost a full mm thicker and longer than the 1976 population.
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