Editing Affinity (taxonomy)
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The number of legs might well be a significant affinity in comparing different types of related organisms such as [[crustacean]]s, but irrelevant in comparing a ten-limbed [[Cephalopoda|cephalopod]] with a ten-limbed [[Solifugae|solifugid]] (including its [[pedipalp]]s as limbs). Such a comparison would be no more cogent than the foregoing example of the lizard and the table. |
The number of legs might well be a significant affinity in comparing different types of related organisms such as [[crustacean]]s, but irrelevant in comparing a ten-limbed [[Cephalopoda|cephalopod]] with a ten-limbed [[Solifugae|solifugid]] (including its [[pedipalp]]s as limbs). Such a comparison would be no more cogent than the foregoing example of the lizard and the table. |
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There are many such examples in nature; we see both a [[lungfish]] and a [[porpoise]] as having closer (but largely different) affinities to a cow than to a [[tuna]], and a [[bat]] as having closer affinities to a [[banteng]] than to a bird or a butterfly, |
There are many such examples in nature; we see both a [[lungfish]] and a [[porpoise]] as having closer (but largely different) affinities to a cow than to a [[tuna]], and a [[bat]] as having closer affinities to a [[banteng]] than to a bird or a butterfly, in spite of the fact that a banteng has no "wings". These are considerations arising from the principles discussed in articles on [[Homology (biology)]] and [[Analogy (biology)]]. |
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It is clear that there is an element of subjectivity to the recognition of affinities; that is implicit in such dictionary definitions as: ""Affinity: the closeness of relation between plants as shown by similarity of important organs."<ref name="BotGloss">Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928</ref> That definition is over a century old, but it is typical of the basis on which taxonomists had to work till recently, and in practice still must use; it is not practical to sequence the genome of every specimen. Nucleic acid analyses are eroding many difficulties, but there is a long way to go. |
It is clear that there is an element of subjectivity to the recognition of affinities; that is implicit in such dictionary definitions as: ""Affinity: the closeness of relation between plants as shown by similarity of important organs."<ref name="BotGloss">Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928</ref> That definition is over a century old, but it is typical of the basis on which taxonomists had to work till recently, and in practice still must use; it is not practical to sequence the genome of every specimen. Nucleic acid analyses are eroding many difficulties, but there is a long way to go. |
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== References == |
== References == |