Term
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Definition
| a derived character state (cf. plesiomorphy). |
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Term
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Definition
| a derived character state (apomorphy) that is restricted to a single terminal taxon in a data set. An autapomorphy at a given hierarchical level may be a synapomorphy at a less-inclusive level. One type of uninformative character. |
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Term
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Definition
| A monophyletic group, made up of an ancestor and all of its descendents. |
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Term
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Definition
| A branching diagram that shows hypothesized phylogenetic (sister-group) relationships of a group of organisms. Do not show the degree of divergence, only the hierarchical pattern. |
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Term
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Definition
| similarity due to inheritance of a feature from a common ancestor. A synapomorphies are homologs. |
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Term
| Homoplasy (adj. homoplasious, homoplastic) |
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Definition
| similarity due to parallelism or reversal of character states. |
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Term
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Definition
| the group under investigation in cladistic analysis to determine its phylogenetic pattern. |
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Term
| Monophyly (monophyletic group) |
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Definition
| a group (clade) that includes a most recent common ancestor plus all and only all of its descendents, and is diagnosed by synapomorphies (shared derived characters). |
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Term
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Definition
| a taxon used in cladistic analysis for comparative purposes, usually with to enable character polarity. |
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Term
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Definition
| an indirect method of character polarization that uses the information on character states in outgroup taxa to determine the relative apomorphy and plesiomorphy of character states found in the ingroup taxa. |
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Term
| Paraphyly (paraphyletic group) |
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Definition
| a group that includes a common ancestor and some, but not all, of its descendents. Diagnosed by symplesiomorphies. |
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Term
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Definition
| an ancestral (primitive) character state |
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Term
| Polyphyly (polyphyletic group) |
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Definition
| a group with two or more (i.e., multiple) ancestors, but not including the true common ancestor of its members. Based on convergent (homoplastic) characters. |
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Term
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Definition
| shared ancestral character state. Paraphyletic groups may result from mistaking symplesiomorphies for synapomorphies. Can also be a type of uninformative character (if shared by all members of the study-group). |
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Term
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Definition
| shared derived character state. Used to define monophyletic groups. |
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Term
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Definition
| one that is not useful in constructing hypotheses of phylogenetic relationships (e.g., autapomorphy, symplesiomorphy). |
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