Question

You are studying aging in two species of fish. You bring them into a common laboratory environment free from factors causing extrinsic mortality and find that species A lives twice as long as species B. Based on the evolutionary theory of aging, you would predict that:

1) species B has lower extrinsic mortality in its natural habitat than species A
2) species B reproduces later in life than species A
3) the average age of individuals in wild populations of species B is higher than species A
4) species B has higher extrinsic mortality in its natural habitat than species A
5) a and c are correct

Answer 1

Species B is likely adapted to higher extrinsic mortality than species A, leading to earlier reproduction and a shorter lifespan. This is supported by the evolutionary theory of aging and life history strategies.

Step-by-step explanation:

The correct prediction based on the evolutionary theory of aging is 4) species B has higher extrinsic mortality in its natural habitat than species A.

According to the evolutionary theory of aging, extrinsic mortality rates play a significant role in shaping lifespan and reproductive strategies. Organisms that face high extrinsic mortality generally reproduce earlier and do not live as long. If species B lives half as long as species A in an environment free of extrinsic mortality factors, we can infer that species B is adapted to greater risks in its natural habitat and thus follows an evolutionary survival strategy of reproducing earlier. This implies higher extrinsic mortality for species B than species A in their natural environments. On the other hand, species A's longer lifespan suggests that it can afford to delay reproduction, indicating a lower extrinsic mortality. These assumptions are based on tradeoffs between reproduction and survival that are foundational to life history strategies, where some species reproduce quickly at the risk of dying early, and other species delay reproduction to grow larger and provide better parental care, which can be advantageous if extrinsic mortality is lower.