Consider the following scenario: A drought hits the habitat of a semi-aquatic bird population. All ponds dry up and fish populations decline. There are two groups of birds in the population that differ in leg length and diet. Long-legged birds eat fish while short-legged birds eat insects. The drought has little effect on the insect populations.

Question

What is the main selective pressure in this scenario?

(1 point)
Responses

fish population
fish population

leg length
leg length

insect population
insect population

drought

Answer 1

The main selective pressure in this scenario is the fish population.

Since the long-legged birds rely on fish as a primary food source and the drought has led to the drying up of ponds and a decline in fish populations, this situation creates a selective pressure against the long-legged birds. The short-legged birds, which eat insects, are less affected by the drought because the insect populations remain stable. Therefore, the fish population decline directly impacts the survival and reproductive success of the long-legged birds.