Systematics and Biogeography: Cladistics and Vicariance Online!

Every now and then a scientific discipline undergoes a revolution, an episode that changes the way a subject is perceived, the way it is understood and undertaken – a new vision emerges that prevents a return to the subject matter as it was before, a paradigm change, some genuine progress. In the last century, there was a revolution in phylogenetics and systematics that began with the work of entomologist Willi Hennig (1950, 1966) and its interpretation by Lars Brundin (1966), a chironomid specialist. The need for revolution was succinctly put by palaeontologist Colin Patterson, some years later

“By about 1960 palaeontology had achieved such a hold on phylogeny reconstruction that there was a commonplace belief that if a group had no fossil record its phylogeny was totally unknown and unknowable” (Patterson 1987:8).

That ‘commonplace belief’ was eventually rejected in favour of determining relationship from evidence (characters, homologies) provided by organisms (living or extinct), a shift from the preoccupation of discovering ancestry directly from the fossil record to determining common ancestry. As Brundin later noted, “little by little some palaeontologists have perceived that Hennig’s principles of phylogenetic systematics meant a revolution to their science.” Hennig called his approach Phylogenetic Systematics, the title of his 1966 book (Hennig 1966), an approach that eventually became known as cladistics, hence the cladistic revolution: the cladistic revolution overturned the central position of palaeontology in determining phylogenetic relationships: turning Ernst Haeckel’s Systematische Phylogenie into Hennig’s Phylogenetic Systematics.

By the early 1980s three books were published, all dealing with cladistics. Each approached its topic from a different perspective: Phylogenetic Analysis and Paleontology by Joel Cracraft & Niles Eldredge (Columbia University Press, New York, 1981), Phylogenetics: The Theory and Practice of Phylogenetic Systematics by Ed Wiley (New York: Wiley Interscience, 1981) and Systematics and Biogeography: Cladistics and Vicariance by Gary Nelson and Norman Platnick (Columbia University Press, New York, 1981).

While all three books have their merits, it is the last, Systematics and Biogeography: Cladistics and Vicariance that broke into new ground; and it is the last that, some 28 years after its first appearance and almost impossible to get a copy, is being made available by the University of California Press at http://www.ucpress.edu/books/series/spsy.php

Cladistics, as outlined in Systematics and Biogeography: Cladistics and Vicariance, might be understood as a reaction to phylogeny reconstruction, or more specifically, Haeckel’s paleontological version of it, developed by Matthews and Simpson. Systematics and Biogeography is a detailed critique of Haeckel’s legacy and an outline of what can be understood as natural classification, as first sketched by Candolle in his Théorie élémentaire de la Botanique – the question addressed being: How do ancestor—descendant relationships relate to natural classification?

Since Systematics and Biogeography there have been discourses on ‘tree-thinking’, ‘group-thinking’ and ‘population-thinking’, none seemingly appropriate for classification: Classification (and phylogeny, and systematics) are all best referred to as relationship-thinking, of which Systematics and Biogeography is a meditation on.

Download this book now from the University of California Press website – and see if you can start another revolution.