Cladistics
Part of the Biology series on
Evolution
Introduction
Mechanisms and processes
Adaptation
Genetic drift
Gene flow
Mutation
Natural selection
Speciation
Research and history
Evidence
Evolutionary history of life
History
Modern synthesis
Social effect
Theory and fact
Objections / Controversy
Evolutionary biology fields
Cladistics
Ecological genetics
Evolutionary development
Human evolution
Molecular evolution
Phylogenetics
Population genetics
Biology Portal ·
Cladistics, from the ancient Greek κλάδος,
klados, "branch", is the hierarchical classific-
ation of species based on phylogeny or evolu-
tionary ancestry. The term phylogenetics is
often used synonymously with cladistics.
Cladistics is distinguished from other taxo-
nomic systems because it focuses on the evol-
utionary relationships of species rather than
on morphological similarities, which may be
convergent, and because it places heavy em-
phasis on objective, quantitative analysis.[1]
Cladistics originated in the work of the
German entomologist, Willi Hennig, who him-
self referred to it as phylogenetic systemat-
ics; the use of the terms "cladistics" and
"clade" was popularized by other research-
ers.[2] Cladistics originated in the field of bio-
logy but in recent years has found application
in other disciplines, for example 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 sequencing data
are used in many important cladistic efforts.
Computer programs are widely used in
cladistics, due to the highly complex nature
of cladogram generation procedures.
Terminology
The yellow group (sauropsids) is monophylet-
ic, 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 (