Taxonomy
Taxonomy is a branch of science. It is about the laws and principles of classifying things.[1] From one type of taxonomy, many classifications might be produced.
The best-known kind of taxonomy is used for the classification of lifeforms (living and extinct). Each lifeform has a scientific name. This name is part of the scientific classification of that species. The name is the same all over the world, so that when scientists from different places talk or write about the living thing, they can understand each other. In addition, a species has a position in the tree of life. Thus the crow is Corvus corone, a member of the Corvidae family, and they are passerine birds. That is well agreed, but the classification of other groups is not agreed at present, and often several classifications are being discussed.
The highest rank in the domain of living things is the kingdom. Each kingdom has many smaller groups in it, called phyla.[2] Each phylum has more smaller groups in it, called classes. This pattern looks like branches on a tree with smaller branches growing from them. Each species is put into a group because of what it does, how and what it eats, special body parts, and so on. At the end of the pattern, the groups (genera) are very small. Then each species in the genus is given its own name.
When someone writes about a living thing and its formal scientific name, they write the genus and species name. This is known as binomial nomenclature, because it is a way to describe organisms using two names, the first is the genus name, and the second is the species in that genus. The scientific name of the domestic cat is Felis catus. Sometimes it is enough to write F. catus.
These are the major groups (ranks) used in taxonomy:
Kingdom --> Phylum --> Class --> Order --> Family --> Genus --> Species
Some mnemonics (sayings to help a person remember something):
- King Phillip Came Over From Greater Spain,
When people started naming species, Latin was the language most widely used around the world. So, all species names are still Latin names. Scientists used to write the official description of each new species in Latin as well. Years ago, zoologist switched from Latin to English for the description of animals. On January 1, 2012, the International Botanical Congress switched to English for describing new plant species.[3]
[change] Cladism
An important modern approach to taxonomy is cladism. This approach is based on the branching (tree-like) course of evolution. Like traditional Linnaean classification, it uses characters (traits) to decide on the branches of the classification. It insists on groups being monophyletic. This has the effect that birds are not a class but a sub-group of dinosaurs. It also means the rank system described above would be abolished. Cladism thus has different principles of taxonomy, and so produces a different kind of classification. Decisions, where possible, are supported by DNA sequence analysis. Present-day biological classification is a mixture of the old Linnaean and the modern cladistic principles of taxonomy. In parts, it is changing rapidly. The classificatons presented in wikipedia at present are often a compromise between the two systems. The details are regularly discussed.
[change] Related pages
[change] References
- ↑ Oxford English dictionary
- ↑ See List of animal phyla
- ↑ Higgins, Adrian (January 19, 2012). "Veni, vidi, vici – and now history". Washington Post. p. A1.
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