[Campbell Biology P.63] A population of fish lives in a lake where a new predator, which pr... | Practice Question

A population of fish lives in a lake where a new predator, which preys on larger fish, is introduced. According to Darwin's reasoning from his observations, what would likely happen to the fish population over many generations?

  • A: The average size of the fish in the population would decrease, as smaller fish are more likely to survive and reproduce.
  • B: All fish would eventually grow larger to better fight off the new predator.
  • C: The fish would consciously adapt by changing their color to blend in with the lake bottom.
  • D: The fish population would quickly become extinct due to the new predation pressure.

Explanation

This scenario directly applies Darwin's third observation: individuals with inherited traits better suited to the local environment are more likely to survive and reproduce. If larger fish are preyed upon, smaller fish would have a survival advantage, reproduce more, and pass on their 'smaller' traits, leading to a decrease in average size over generations due to natural selection.