 How does the concept of species help organize the study of evolution, according to Novak and Doolittle? The general concept of species consists of what they call “conceptual patchworks.” Those conceptual patchworks are the various species concepts we have seen, such as the Biological Species Concept and the Ecological Species Concept. These patchwork concepts interact and contribute to our understanding of speciation. For instance, the Biological Species Concept was first developed for multicellular organisms, but more recently ideas from that concept have been applied to microorganisms. The result is a patchwork version of the Biological Species Concept that applies to multicellular organisms and another version that applies to microorganisms. (See Section 4 of this entry for more on microbiology and species.)