Unit three natural selection unit lesson 12 natural selection unit test 14 questions 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 link and diet. Long legged, birds, eat, fish, white short legged birds, eat insects the drought has a little effect on insect populations. What is the main selective pressure in this scenario? Is it drought leg length insect population or fish population?
The main selective pressure in this scenario is the fish population decline. The drought has caused all ponds to dry up, leading to a decrease in fish populations. This directly affects the long-legged birds, as they primarily eat fish. The decrease in fish availability puts selective pressure on the long-legged birds, as it becomes more difficult for them to obtain their main food source. On the other hand, the drought has little effect on insect populations, which are the main food source for the short-legged birds.
