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Characters, taxonomic groups, and relationships in botany 1770–1850 as exemplified by the work of Henri Cassini
Author(s) -
Stevens Peter F.
Publication year - 2009
Publication title -
taxon
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 81
eISSN - 1996-8175
pISSN - 0040-0262
DOI - 10.1002/tax.581006
Subject(s) - affinities , extant taxon , taxon , hierarchy , analogy , darwin (adl) , taxonomic rank , origin of species , charles darwin , type (biology) , group (periodic table) , epistemology , evolutionary biology , genealogy , biology , history , ecology , philosophy , darwinism , chemistry , computer science , biochemistry , software engineering , organic chemistry , economics , market economy
Using the French botanist Henri Cassini's work as an example, the complex relationship between characters, groups and relationships in the period 1770–1850 is explored. Cassini thought that classifications should be natural and that groups were to be based on numerous characters, although they would be difficult to recognize and characterize. For the most part he saw relationships between organisms as two dimensional, with one group directly joining two or more other groups. At the same time he asserted that the best way to think about affinities was as if they were linear, largely because this was most compatible with how he thought that the human mind worked. When he discussed relationships between individual plant parts he used words like type, analogy, and hypothesis that were rarely used when he discussed relationships between groups. In Cassini's writings it is difficult to connect his work on the analogies between plant parts with his ideas of affinities between groups. In the early nineteenth century zoologists in particular were developing various ways of thinking about organisms as being related indirectly, whether using abstract types or the taxonomic hierarchy to structure relationships. Similarly, Darwin's discussion of affinities between groups was separate from that on homologies between particular structures, but he saw relationships as being like a tree, with extant taxa being related indirectly by their ancestors.