Question

A biologist studied a population of squirrels for 15 years. over that time, the population was never fewer than 30 squirrels and never more than 45. her data showed that over half of the squirrels born did not survive to reproduce, because of competition for food and predation. suddenly, the population increased to 80. in a single generation, 90% of the squirrels that were born lived to reproduce. what inferences might you make about that population?

Answer 1

Out of the following given choices;

A) The amount of available food may have increased.

B) The parental generation of squirrels developed better eyesight due to improved diet; the subsequent squirrel generation inherited better eyesight.

C) The number of predators that prey upon squirrels may have decreased.

D) The amount of available food may have increased and/or the predators that prey upon squirrels may have decreased.

The answer is D. Predation was most probably a selection pressure that maintained the numbers of squirrels at 30 – 45. A decrease in predator numbers would cause a rise in the prey (squirrel population). Additionally, the availability of food may also have been a limiting factor. Increase in food in the habitat would increase the carrying capacity of squirrels in the habitat.