12.2: Ecological communities are complex

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Before proceeding with simplified models of predation, we want to stress that ecological communities are complex (Figure \(\PageIndex{1}\)). Fortunately, progress in understanding them comes piece by piece. Complex food webs, like the one illustrated in the figure, can be examined in simpler “motifs.”

You have seen in earlier chapters that there are two motifs for a single Species: logistic and orthologistic, with exponential growth forming a fine dividing line between them. And in the prior chapter, you saw three motifs for two species: predation, competition, and mutualism.

Later you will see that there are exactly forty distinct three-species motifs, one of which is two prey pursued by one predator. This is called “apparent competition” because arrows 2.JPG it has properties of competition.

Food Web.JPG — Figure \(\PageIndex{1}\). *Cretaceous terrestrial food web, Mitchell et al. 2012 PNAS.*