Question

Based on their observations and the data they collected, the Grants concluded that evolution by natural selection had occurred in the medium ground finch population. The increase in the average beak size of the offspring was a direct result of the change in the food supply during the drought. In order to have reached this conclusion, the Grants must have either assumed or proven that several other facts about the finch population were true. Which statements represent information that must be true in order for the Grants conclusion to be correct? Select the three statements that must be true.
A) An individual finch’s beak size can change depending on the size of the seeds it eats.
B) The drought caused a mutation that led to larger beak sizes in the finch population.
C) Beak size is an inherited trait in the finch population under study.
D) Birds that could eat larger, tougher seeds survived and reproduced during the drought.
E) Beak size varies among the birds in the finch population under study.

Answer 1

Answer:

C. Beak size is an inherited trait in the finch population under study.

D. Birds that could eat larger, tougher seeds survived and reproduced during the drought.

E. Beak size varies among the birds in the finch population under study.

Explanation:

The presence of genetic variations among the individuals of a population is required for natural selection to be operative. Natural selection targets the beneficial genetic variations present in the population. Natural selection refers to the differential reproductive and survival success of organisms of a population due to some beneficial genetic traits. These organisms with beneficial genetic traits are able to survive and leave more progeny under prevailing conditions.

If the natural selection has occurred in the ground finch population for the beak size, the beak size should be a genetic trait since natural selection works on genetic traits only. The finch population should have variations with respect to the beak size. The finches having the larger beak size that enabled them to feed on larger, tougher seeds should have higher survival and reproductive fitness during the drought.

Under these conditions, natural selection would favor the finches with larger beak size and would eventually result in an increase in the average beak size of the future generations.