Cladistics
Part of the Biology series on
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Adaptation
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Research and history
Evidence
Evolutionary history of life
History
Modern synthesis
Social effect
Theory and fact
Objections / Controversy
Evolutionary biology fields
Cladistics
Ecological genetics
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Phylogenetics
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Biology Portal ·
Cladistics,
from the ancient Greek κλάδος, klados,
"branch", is the hierarchical classification of species
based on phylogeny or evolutionary ancestry. The term
phylogenetics is often used synonymously with cladistics.
Cladistics is distinguished from other taxonomic systems
because it focuses on the evolutionary relationships of
species rather than on morphological similarities, which
may be convergent, and because it places heavy emphas-
is on objective, quantitative analysis.[1]
Cladistics originated in the work of the German ento-
mologist, Willi Hennig, who himself referred to it as
phylogenetic systematics; the use of the terms "cladistics"
and "clade" was popularized by other researchers.[2]
Cladistics originated in the field of biology but in recent
years has found application in other disciplines, for ex-
ample in Textual criticism to determine the relationship
between the surviving manuscripts of the Canterbury
Tales[3]
Cladistics generates diagrams called cladograms that
represent the evolutionary tree of life. DNA and RNA se-
quencing data are used in many important cladistic ef-
forts. Computer programs are widely used in cladistics,
due to the highly complex nature of cladogram genera-
tion procedures.
Terminology
The yellow group (sauropsids) is monophyletic, the blue group
(reptiles) is paraphyletic, and the red group (warm-blooded
animals) is polyphyletic.
• A clade is an ancestor and all of its descendents
• A monophyletic group is a clade
• A paraphyletic group is a monophyletic group that
excludes some of the descendants (e.g. rep