If a bird that eats grasshoppers moved to the prairie, how would this move affect the natural selection for grasshopper colour ( brown and green ) in wet years? in drought years?
1 Answer
In wet years the green grasshopper population will increase.
And in drought years the brown grasshopper population will increase.
Explanation:
Natural selection is the process where the animal (or any organism) with favorable traits (=advantages) are more likely to reproduce. Which in time cause an increase in its population, sometimes over other populations sharing the same habitat (since they fight for the same resources.
In our case the green grasshopper as a clearly favorable trait(=advantage) while the grass is green, since they can easily hide in it. What cases less decries in its population by the birds, and more reproduction. 
But in drought, it's turned around since the grass is dry and brownish the brown grasshopper as the advantage this time.
