Example: A(n) ________ is green, each off spring is a slightly different shade of green than each other if the leaves of the trees that they live in is a light green, the dark and medium birds are less likely to survive due to their pray being more likely to spot them for natural selection to occur, a population must have a wide variety of organisms and traits which means it is a much slower and in some cases non- existent in species who reproduce asexuallyartificial selection.