摘要
Cladistics is a biological philosophy that uses genealogi-cal relationship among species and an inferred sequence of divergence as the basis of classifi cation.This review critically surveys the chronological development of bio-logical classification from Aristotle through our post-genomic era with a central focus on cladistics.In 1957,Julian Huxley coined cladogenesis to denote splitting from subspeciation.In 1960,the English translation of Willi Hennig’s 1950 work,Systematic Phylogenetics,was published,which received strong opposition from phenet-icists,such as numerical taxonomists Peter Sneath and Robert Sokal,and evolutionary taxonomist,Ernst Mayr,and sparked acrimonious debates in 1960-1980.In 1977-1990,Carl Woese pioneered in using small subunit rRNA gene sequences to delimitate the three domains of cellu-lar life and established major prokaryotic phyla.Cladistics has since dominated taxonomy.Despite being compatible with modern microbiological observations,i.e.organisms with unusual phenotypes,restricted expression of charac-teristics and occasionally being uncultivable,increasing recognition of pervasiveness and abundance of horizon-tal gene transfer has challenged relevance and validity of cladistics.The mosaic nature of eukaryotic and prokary-otic genomes was also gradually discovered.In the mid-2000s,high-throughput and whole-genome sequencing became routine and complex geneologies of organisms have led to the proposal of a reticulated web of life.While genomics only indirectly leads to understanding of func-tional adaptations to ecological niches,computational modeling of entire organisms is underway and the gap between genomics and phenetics may soon be bridged.Controversies are not expected to settle as taxonomic classifi cations shall remain subjective to serve the human scientist,not the classifi ed.
