Ghiselin is famous for his work on
sea slugs, and had both a species (
Hypselodoris ghiselini) and the
defensive chemical that it contains (
ghiselinin) named after him. In 2009 he co-authored a major study on chemical defense with Guido Cimino:
Chemical Defense and the Evolution of Opisthobranch Gastropods. . In 1969 he proposed three models including the size-advantage model to explain
sequential hermaphroditism. In some fish species, he reasoned, males can maximize their reproductive success by breeding with a harem of females rather than breeding only once as a female. In other species, where the fish live in pairs, it is to an individual's advantage to be male when small and to turn into a female when it is larger. Ghiselin worked on the history and philosophy of
evolutionary biology. His historical publications dealt mainly with
Darwin and the history of
comparative zoology. They include such topics as the influence of alchemy on nineteenth century zoology and the history of the Zoological Station at Naples, Italy. His thought on Darwin's view of selection, whether to the individual or to the group, and sometimes apparently
kin selectionist, has been criticised as inconsistent by the Darwinian philosopher
Helena Cronin. He criticised the falsification of the history of
Lamarck's theory of evolution, where in his view schoolbooks and "textbook-writers have imbued the fictitious Lamarck with an importance that the real Lamarck never had, and they have credited him with ideas that the real Lamarck did not hold. They have invented a myth in which those ideas are compared falsely with Darwin's ideas, to produce a bogus dichotomy." He has also criticized the views of
creationists as non-scientific. His main contribution to philosophy concerns the principles of classification (systematics or taxonomy). He is given much of the credit for first theorizing that biological species are not
kinds of organisms, but are rather
individuals in a philosophical sense (in the manner that an individual population is an individual entity, rather than an abstract type). A human being is not a
Homo sapiens for the same reason that
Ontario is not a Canada. Ghiselin was the originator of the term "chunks of the genealogical nexus" to describe species. Ghiselin had many interdisciplinary interests, among which was forging links between biology and
economics. He was Vice President of the International Society for Bioeconomics, and served as the Co-Editor of the
Journal of Bioeconomics since it was established in 1998. The first academic chair of
bioeconomics was established at the
University of Siena; as a visiting professor he was its first occupant. As Chair of the Center for the History and Philosophy of Science his main responsibility was to organize scholarly meetings and to serve as Editor of the volumes based on them. He was made a Guggenheim fellow in 1978. == Works ==