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)

Leg length

insect population

O drought

fish population

Answer 1

The main selective pressure in this scenario is the fish population. The drought causes the ponds to dry up, leading to a decline in fish populations, which directly affects the long-legged birds that rely on fish as their primary food source. As a result, the long-legged birds face greater survival challenges due to the reduced availability of their food, while the short-legged birds, which eat insects, are less affected since the insect population remains stable.