Question

The most likely explanation for the increase in average beak size of the medium ground finch is that the

• A. Trait is inherited and birds with larger beaks have greater reproductive success.
• B. Lack of small seeds caused a mutation which resulted in a larger beak.
• C. Birds interbred with a larger-beaked species and passed on the trait.
• D. All of the above.

Answer 1

The correct option is B

Lack of small seeds caused a mutation which resulted in a larger beak.

Lamarck believed that acquired characters are passed on from one generation to the other but it happens only when there is a change in genetic material else changes acquired by an individual are not passed to next generation. For example, in this passage, the lack of small seeds pushed birds to acquire large beaks. What is the reason to assume that such a large beak will be passed on to next generation? Other options describe the possibility how large beak character can be passed on by one generation to the next. Hence other options may be correct assumption while option B is a classical Lamarckian conclusion.