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 a little effect on insect populations.

Question

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 a little effect on insect populations.

What is the main selective pressure in this scenario?
A. drought
B. insect population
C. leg length
D. fish population

Answer 1

A. drought

The main selective pressure in this scenario is the drought, as it is directly impacting the availability of the birds' primary food source (fish) by causing the ponds to dry up and fish populations to decline. This will in turn affect the survival and reproductive success of the long-legged birds that rely on fish for their diet.