Willi HennigDied 5 Nov 1976 at age 63 (born 20 Apr 1913).German zoologist who proposed cladistics (Greek=branch) for the hierarchical classification of species, based on phylogeny - the evolutionary history - of the ancestors. He wished to deal with deficiencies in the system originated by Linnaeus. Hennig published a new system in his book, Theorie der phylogenetischen Systematik in 1950. Cladistics regards all new species to have evolved by descent with modification. After an evolutionary branching, some shared derived characteristics are retained. Thus the evolutionary history of current organisms can be traced back, connecting through shared ancestors to lineages of other organisms. For example, the even-toed foot of the deer, camels, cattle, pigs and hippopotamus is a homologous similarity indicating a common ancestor.« |
