1. 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 insect populations. What is the main selective pressure in this scenario?

Question

1.	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 insect populations. What is the main selective pressure in this scenario?

GPT-4o mini · Answer

In this scenario, the main selective pressure is the availability of food resources, specifically the decline of fish populations due to the drought. Since long-legged birds rely on fish as their primary food source and fish populations are declining, these birds will experience higher competition for food and may struggle to survive and reproduce.

In contrast, short-legged birds, which eat insects, are less affected by the drought since insect populations are relatively stable. As a result, short-legged birds may have a survival advantage in this scenario. Therefore, the selective pressure favors short-legged birds over long-legged birds, leading to potential changes in the population dynamics and physical traits within the bird population over time.