Question

Which group will evolve faster (under the same conditions): a population of sharks, or a population of small herbivorous fish - both are in the ocean.

Answer 1

The rate of evolutionary change in a population in the absence of natural selection (genetic drift) depends on two major factors - generation time and population size.

Species with short lifespans tend to breed much faster. This allows them to change the genetic makeup of the population much faster. On the contrary, large population sizes slow down the evolution rate.

Since, sharks have a larger lifespan as compared to small herbivorous fish and assuming same population size for both (since no information about population size is provided), therefore, small herbivorous fish will evolve faster.