The main selective pressure in this scenario is the fish population. The significant decline in fish populations directly affects the long-legged birds that rely on fish as their primary food source. Since the short-legged birds eat insects, which have a stable population, they are less impacted by the decline in fish. Therefore, the availability of food resources (fish) creates a selective pressure that influences the survival and reproductive success of the long-legged birds.
Consider the following scenario:
A significant decline in fish populations occurs in the habitat of a semi-aquatic bird population. 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 insect population remains stable.
What is the main selective pressure in this scenario?
leg length
bird population
fish population
insect population
1 answer