There are two different species of single-cell organisms (each organism consists of only one cell) living in the same environment. The two are identical except that the members of one species are four times larger than the other species. Suddenly their environment becomes dramatically worse: the nutrients that each species requires become far less abundant than before. Under this set of now-unfavorable conditions the numbers of individuals of the smaller single-cell species remained constant for quite a while before the population began to decrease as the small-cell organisms died from starvation. In contrast, the larger single-cell organisms started to die very soon after the change of environment and completely disappeared long before the smaller ones disappeared. Explain this difference in response to a changed environment.