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Correct! The tallest red bar is at 8.8 mm. This means a greater number of finches in the original population had a beak depth of 8.8 mm (around 48 birds) than any other beak depth. The black bar at 8.8 mm on the other hand is very small, which means very few birds with this beak depth survived the drought. Select another correct answer. You selected all the correct answers.
Correct! Together, the black bars fill less than half of all the red bars, which means that fewer than half of the birds of the initial population survived the drought. Select another correct answer. You selected all the correct answers.
It’s true that the most common beak depth of the surviving population was 10.3 mm as the tallest black bar is 10.3 mm. However, this black bar is just a bit less than half of the red bar, which means that nearly half (~40%) of the individuals with beak depths of 10.3 mm from the initial population survived the drought. Try again.
Correct! Most of the survivors of the 1977 drought had larger beaks. When small seeds became scarce after the drought, more medium ground finches with smaller beaks ran out of food and died. Finches with larger beaks were better able to eat the larger, harder seeds. Select another correct answer. You selected all the correct answers.
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Correct! If you compare the red bars in the first graph to the red bars in the second graph, the distribution is skewed to the right in the second graph, which is an indication that, on average, beak depth increased. The film mentions that the average beak depth of the population increased by more than 4% in just one generation. Select another correct answer. You selected all the correct answers.
Most finches that survived the drought had beak depths of 9.8 mm and 10.3 mm. The most common beak depth of the offspring was around 9.3 mm and 9.8 mm. So the beaks of the offspring were not much larger than those of their parents. Try again.
The range of offspring beak depths is larger than that of the parents that survived the 1977 drought (black bars). The range is 7.3 mm to 11.3 mm for the offspring and 7.8 mm to 10.8 mm for the parents. Try again.
The 1978 offspring population shows recovery; their numbers (~120) far exceed those of their drought-surviving parents (~40). However, they do not outnumber the ~200 birds in the initial population before the drought. Try again.
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