Visualizations of the Messel lake and forest food webs: (left) lake food web, (right) forest food web. Spheres represent species and lines represent feeding links. Links that loop indicate cannibalism. The vertical axis corresponds to trophic level, with plants at the bottom level. Colors of nodes correspond to taxonomic affiliation of species. green = plants, algae, and diatoms; blue = bacteria, fungi, and detritus; yellow = invertebrates; orange = vertebrates.