Developing an understanding of the nature of food webs is an important topic in today's biology curricula. The relationships represented in a food web are rule-like in nature. Hence, it should be possible to construct a learning hierarchy for this concept. A hierarchy leading to the ability to determine how a change in the size of one population can affect another population in the same web but not on the same chain was hypothesized. Data from 200 subjects were extremely consistent with the hierarchy. A second major focus related to the identification of specific misconceptions held by subjects for food webs. The need to identify students' misconceptions of important concepts has been expressed widely in the recent science education literature. In the present article, an argument is presented for the usefulness of learning hierarchies in this work. Specific misconceptions and the frequencies of their occurrence are reported.