Answer:
How does a change in food resources model the type of beaks in birds?
Explanation:
We know that phenotype results from the interaction of the genotype and the environment. Any change in the environment produces a change in the phenotype of the animals. By performing this experiment, we probably want to know the influence of the environment on animals. In this particular example, we change a source of food by removing fruit (which would be acting as the independent variable of the experiment) and evaluate its effects on the birds´ beak (the dependent variable). Which of the three different beaks increases their frequencies by removing the fruit, and which one decreases its frequency.
So here, the absence of fruit is acting as a selective ecological pressure on birds. It is modeling birds´ beaks and adapting animals to feed on some other resource.
