Analysis of forelimb anatomy of humans, bats, and whales shows that humans and bats have fairly similar skeletal structures, while whales have diverged considerably in the shapes and proportions of their bones. However, analysis of several genes in these species suggests that all three diverged from a common ancestor at about the same time. Which of the following is the best explanation for these data?
You gave no choices.
a. Evolution of human and bat forelimbs was adaptive, but not for whales.
b. Humans and bats evolved by natural selection and whales evolved by Lamarckian mechanisms.
c. Whales are not properly defined as mammals.
d. Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.
e. Genes mutate more rapidly in whales than in humans or bat
I am thinking a, if they mean adaptive radiation...
does anyone know?
I would choose d.
The best explanation for these data is convergent evolution. Convergent evolution occurs when different species independently evolve similar traits or characteristics due to similar environmental pressures. In this case, humans and bats share similar forelimb anatomy because they both adapted to flying. However, whales, although they also evolved from a common ancestor, have a different evolutionary history and adapted to life in the water, resulting in their divergent forelimb anatomy.
To arrive at this explanation, there are a few steps you can follow:
1. Understand the question: The question states that humans and bats have similar skeletal structures in their forelimbs, while whales have diverged considerably. The genes suggest that they all diverged from a common ancestor at the same time. The question asks for the best explanation for these data.
2. Identify the relevant information: The relevant information includes the comparison of forelimb anatomy, the divergence from a common ancestor, and the similarity in gene analysis.
3. Consider the concept of convergent evolution: Convergent evolution refers to the independent development of similar characteristics in different species due to similar environmental conditions or selective pressures. It can explain why humans and bats share similar forelimb anatomy even though they are not closely related.
4. Apply the concept to the question: Based on the information provided, it suggests that humans and bats adapted a similar forelimb structure to fly, independently from their common ancestor. On the other hand, whales adapted differently to live in water, resulting in a divergent forelimb anatomy.
Therefore, the best explanation for these data is convergent evolution, as it accounts for the similarities in forelimb anatomy between humans and bats, as well as the divergence in whales.