Ecology: Concepts and Applications 4th Edition by Manual Molles

Exercise 4

In chapter 14 we have seen how a herbivorous stream insect controls the density of its food organisms, how a herbivorous moth larva and pathogenic microbes combine to control an introduced cactus population, and how decimation of a red fox population led to increases in the populations of the foxes'prey.We do not know the specific environmental factors controlling most populations. Explain why such factors must exist. (Hint: Think back to our discussions of geometric and exponential growth in chapter 11).