Clade

A clade is a term belonging to the discipline of cladistics. For all practical purposes it will usually refer to :

a branch in a cladogram, which is a diagram in the form of a tree resulting from a cladistic analysis.
a monophyletic group of organisms, i.e. a group of organisms which share a common ancestor and which includes the ancestor and all the descendants of that ancestor.

Strictly speaking, a clade is a scientific hypothesis of evolutionary relationships among the organisms included in the analysis, based on the data considered in a cladistic analysis. Therefore, it will depend upon the data used to produce it; a particular clade may be supported or disproved by a subsequent analysis using different data.

If a clade proves robust in different analyses using different kinds of data, it may be translated to taxonomy: it will become a taxon, and may get a formal name and a rank. The idea that all taxa should be clades enjoys widespread support, but it remains controversial. A clade may or may not conform to an existing taxon, and vice versa: see also grade.

The PhyloCode is an attempt at a Code that would allow clades to get a formal name.

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Topics in phylogenetics
Relevant fields: phylogenetics | computational phylogenetics | molecular phylogeny | cladistics
Basic concepts: synapomorphy | phylogenetic tree | phylogenetic network | long branch attraction
Phylogeny inference methods: maximum parsimony | maximum likelihood | neighbour joining | UPGMA
Current topics: PhyloCode | DNA barcoding
List of evolutionary biology topics

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Basic topics in evolutionary biology
Processes of evolution: adaptation - evidence - macroevolution - microevolution - speciation
Mechanisms: selection - genetic drift - gene flow - mutation
Modes: anagenesis - catagenesis - cladogenesis
History: History of evolutionary thought - Charles Darwin - The Origin of Species - modern evolutionary synthesis
Subfields: population genetics - ecological genetics - human evolution - molecular evolution - phylogenetics - systematics - evo-devo
List of evolutionary biology topics | Timeline of evolution | Timeline of human evolution

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