Classification Writing
Animals are belong to 2 group: Vertebrates and
Invertebrates. Vertebrates examples of reptiles, birds, fish, mammals and
amphibians. Invertebrates examples of protozoa, coelenterates, flatworms,
arthropods, annelid worms, molluscs and echinoderms. Arthropods examples of
arachnids, crustaceans, insects and myriapods.
Phenetic versus
Cladistic classification of Birds
Given the phylogeny at top left, a phenetic classification
scheme (above, middle) will emphasize the perceived dissimilarity of birds from
scaly tetrapods, whereas a cladistic scheme (above, right) will
emphasize the more recent common ancestry of birds with crocodiles.
Modern phylogenetic classifications emphasize character
analyses, which show that birds are derived from dinosaurs: that is,
perceptions of bird distinctiveness have changed. Popular discussions
(e.g., "Jurassic Park") present this character analysis
as showing that "dinosaurs are more similar to birds": that
is, perceptions of dinosaur "primitiveness" have changed. This
"neo-phenetic" analysis (below) produces a phylogenetic pattern from
phenetic criterion.
[A note on terminology: systematists favouring
phenetic and cladistic approaches both claim to be doing phylogenetic taxonomy.
The latter term is now more closely associated with cladistic taxonomy, whereas
phenetics remains associated with 'traditional taxonomy'].
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