Malacology Malacology Malacology is the branch of invertebrate zoology that deals with the study of the Mollusca (mollusks or molluscs), the second-largest phylum of animals in terms of described species after the arthropods. Mollusks include snails and slugs, clams, octopus and squid, and numerous other kinds, many of which have shells. One division of malacology, conchology, is devoted to the study of mollusk shells. Malacology derives from Greek , "malakos", "soft"; and , "-logia". Fields within malacological research include taxonomy, ecology and evolution. Applied malacology studies medical, veterinary, and agricultural applications, for example mollusks as vectors of disease, as in schistosomiasis.
Branches of science used in later efforts in other fields, such as the action theory of Alcott Parsons and the system-theory of Nickolas McLuhan. In this context the word "systems" is used to refer specifically to self-regulating systems, i.e. that are self-correcting through feedback. Self-regulating systems are found in nature, including the physiological systems of our body, in local and global ecosystems, and in climate. "Theoretical computer science" (TCS) is a division or subset of general computer science and focuses on more abstract or mathematical aspects of computing. These divisions and subsets include analysis of algorithms and formal semantics of programming languages. Technically,