| rdfs:comment
| - A clade (from ancient Greek, klados, "branch") is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants. The common ancestor of any reasonably-sized group, and most of its descendants, will usually be long dead. It is not necessary for a clade to contain any living representatives.
- As the end result of a cladistic analysis, tree-like relationship-diagrams called "cladograms" are drawn up to show different hypotheses of relationships. A cladistic analysis can be based on as much or as little information as the researcher selects. Modern systematic research is likely to be based on a wide variety of information, including DNA-sequences (so called "molecular data"), biochemical data and morphological data. Willi Hennig (1913-1976) is widely regarded as the founder of cladistics.
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| abstract
| - As the end result of a cladistic analysis, tree-like relationship-diagrams called "cladograms" are drawn up to show different hypotheses of relationships. A cladistic analysis can be based on as much or as little information as the researcher selects. Modern systematic research is likely to be based on a wide variety of information, including DNA-sequences (so called "molecular data"), biochemical data and morphological data. In a cladogram, all organisms lie at the leaves, and each inner node is ideally binary (two-way). The two taxa on either side of a split are called sister taxa or sister groups. Each subtree, whether it contains one item or a hundred thousand items, is called a clade. A natural group has all the organisms contained in any one clade that share a unique ancestor (one which they do not share with any other organisms on the diagram) for that clade. Each clade is set off by a series of characteristics that appear in its members, but not in the other forms from which it diverged. These identifying characteristics of a clade are called synapomorphies (shared, derived characters). For instance, hardened front wings (elytra) are a synapomorphy of beetles, while circinate vernation, or the unrolling of new fronds, is a synapomorphy of ferns. Willi Hennig (1913-1976) is widely regarded as the founder of cladistics.
- A clade (from ancient Greek, klados, "branch") is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants. The common ancestor of any reasonably-sized group, and most of its descendants, will usually be long dead. It is not necessary for a clade to contain any living representatives.
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