Understanding the functioning of ecosystems requires the understanding of the interactions between consumer species and their resources. How do these interactions affect the variations of population abundances? How do population abundances determine the impact of predators on their prey? The view defended in this book is that the "null model" that most ecologists tend to use is inappropriate because it assumes that the amount of prey consumed by each predator is insensitive to the number of conspecifics. The authors argue that the amount of prey available per predator, rather than the absolute abundance of prey, is the basic determinant of the dynamics of predation. This so-called ratio dependence is shown to be a much more reasonable "null model."

A famous ecologist and a philosopher of science team up to offer a fresh new approach to population biology and ecology. Challenging the traditionally accepted Lotka-Volterra model, which is based on predator-prey interactions, this new model emphasizes maternal effects, specifically the significance of a mother's interest in the success of her female offspring.