Concepts of Systematic Biology from Linnaeus to the Present (1707-2007): Three Hundred Years of Progressive Change
Mishler, Brent D. .
Three centuries of paradigm changes in biological classification: is the end in sight?
Classification has been a centerpiece of biology ever since Linnaeus. But the basis of biological classification has gone through a series of upheavals over that time, from being considered a plan in the mind of the creator, to a neutral assessment of overall similarity, to a reflection of evolutionary niches, and finally to a phylogenetic mapping on the tree of life. There are four desirable criteria for taxonomies: (1) practicality: names should easy to apply, stable and clear; (2) information content: names should index an optimal summarization of what is known; (3) predictivity: named groups should maximally predictive of unknown features; (4) function in theories: a classification should capture entities acting in, or resulting from, major natural processes. These criteria flow from #4 to #1; representing an important natural process in the structure of a classification will lead to the other criteria. Evolution is the single most powerful process underlying biological diversity, producing an ever-branching phylogenetic tree through descent with modification along the branches. This results in life being organized as a hierarchy of nested monophyletic groups, and most systematists now feel that the general biological classification system should be used to name these. However, there still remains controversy about how exactly to do that. Many researchers are resigned to using the existing codes of nomenclature to name monophyletic groups, but two major problems arise when attempting this (both stemming from the pre-evolutionary origin of these codes): (1) impossibility of precisely specifying which clade is being named using only one type specimen, and (2) the incomparability of taxonomic ranks under a phylogenetic worldview. The developing Phylocode is an attempt to address these problems (while retaining many other unproblematic aspects of the current codes) to produce an truly phylogenetic classification system. Thus there may be another paradigm shift brewing!
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1 - University of California, Berkeley, Department of Integrative Biology, 1001 Valley Life Sciences Bldg. #2465, Berkeley, California, 94720-2465, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Stevens 1/Hilton
Date: Wednesday, July 11th, 2007
Time: 10:30 AM