A drought hits the habitat of 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?
The main selective pressure in this scenario is the availability of food. As the drought causes ponds to dry up and fish populations to decline, long-legged birds that depend on fish for their diet may struggle to survive and reproduce. Short-legged birds that feed on insects, which are less affected by the drought, may have a better chance of survival and passing on their genes. Therefore, the selective pressure in this scenario favors short-legged birds and their insect-based diet.
The main selective pressure in this scenario is the decline in fish populations due to the drying up of ponds during the drought.
The main selective pressure in this scenario is the availability of food resources. Due to the drought, all the ponds have dried up, leading to a decline in fish populations. This creates a scarcity of fish as a food source for the long-legged birds, which primarily rely on fish for their diet. However, the insect populations remain unaffected by the drought, so the short-legged birds, which primarily rely on insects for their diet, still have access to their food source.
The selective pressure in this case is the reduced availability of fish, which affects the long-legged birds' ability to obtain their preferred food source. As a result, the long-legged birds may struggle to find enough food to survive and reproduce successfully.
In this scenario, the selection pressure is favoring the short-legged birds with their ability to adapt by switching their diet to insects, which are still plentiful. Their ability to exploit an alternative food source allows them to maintain their food supply and have a higher chance of survival and successful reproduction.
To summarize, the main selective pressure in this scenario is the scarcity of fish, which impacts the long-legged birds' survival and reproductive success, while the availability of insects allows the short-legged birds to adapt and sustain their population.