Classification of Hominin Species
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There are many different techniques by which different hominin species are classified. Collard and Wood (2000) tested the phylogenetic utility of quantitative rather than qualitative craniodental data to assess the likely reliability of standard hominin cranial and dental characters for interspecific and intergeneric phylogenetic reconstruction. They used hominin cladistic methods to analyze comparable characters from two groups of extant primates: the higher primate group most closely related to fossil hominins - hominoids, and the Old World monkey tribe consisting of baboons, mangabeys and macaques - the papionins. The resulting cladograms were then judged against the groups= consensus molecular phylogenies, with the hypothesis that congruence between morphological and molecular phylogenies would indicate equivalent hominin fossil evidence yields reliable phylogenies, and incongruence would indicate the opposite. The hypothesis proposed by Collard and Wood was not supported by the parsimony analyses of the two quantitative data sets. The hominoid data resulted in a cladogram with a branching pattern different from that of the hominoid molecular cladogram. Similarly, the papionin cladogram obtained from the craniodental data differed from that of the papionin molecular cladogram. Using the qualitative data, the parsimony analysis of the hominoid qualitative matrix agreed with the hominoid molecular cladogram only in locating Hylobates as the basal hominoid, but differ
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the authors see no reason that eventually the technique can=t be extended to include them. Using the molecular data, the authors have grouped humans and chimpanzees into a subtribe, Hominina to give them a cladistic position among the primates. They point out that relatively small genetic changes can result in large phenotypic changes, and this may explain the seemingly incongruent fact that morphological evolutionary changes seem to have proceeded faster in humans than molecular changes when compared to the other primates.
Of the three methods of classifying hominoids phylogenetically, it would seem that the DNA evidence would be the most reliable, although it is not totally without problems because of the huge effect one simple mutation can cause. However, it would seem to offer the most reliable evidence otherwise by taking things down to the molecular level where empirical testing can take place, as opposed to morphological evidence which is at best microscopic (tissue comparisons) and at worst gross observational (craniodental). Given the current advances in DNA fingerprinting, it no doubt offers the most accurate and reliable analyses available at this time, and should provide dramatic evidence of the branching points o
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Approximate Word count = 1868
Approximate Pages = 7 (250 words per page)
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