Clade

A clade from organisms that are monophyletic – that is, composed of the common ancestor together with all its lineal descendants – on the phylogenetic tree. Rather than the English term, the equivalent Latin term cladus plural cladi is often used in taxonomical literature.

The common ancestor may be an individual, a population, or a species extinct or extant. Clades are nested, one in another, as used to refer to every one of two or more people or matters branch in reform splits into smaller branches. These splits reflect evolutionary history as populations diverged & evolved independently. Clades are termed monophyletic Greek: "one clan" groups.

Over the last few decades, the cladistic approach has revolutionized biological generation and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are non clades; that is, taxa that are non monophyletic. Some of the relationships between organisms that the molecular biology arm of cladistics has revealed put that fungi are closer relatives to animals than they are to plants, archaea are now considered different from bacteria, and multicellular organisms may make evolved from archaea.

The term "clade" is also used with a similar meaning in other fields besides biology, such(a) as Cladistics § In disciplines other than biology.

History of nomenclature and taxonomy

The conviction of a clade did not make up in pre-Darwinian Linnaean taxonomy, which was based by necessity only on internal or external morphological similarities between organisms. numerous of the better required animal groups in Linnaeus' original Systema Naturae mostly vertebrate groups shit equal clades. The phenomenon of convergent evolution is responsible for numerous cases of misleading similarities in the morphology of groups that evolved from different lineages.

With the increasing realization in the number one half of the 19th century that vintage had changed and split through the ages, classification increasingly came to be seen as branches on the evolutionary tree of life. The publication of Darwin's theory of evolution in 1859 provided this view increasing weight. Thomas Henry Huxley, an early advocate of evolutionary theory, reported a revised taxonomy based on a concept strongly resembling clades, although the term clade itself would not be coined until 1957 by his grandson, Julian Huxley. For example, the elder Huxley grouped birds with reptiles, based on fossil evidence.

German biologist Emil Hans Willi Hennig 1913–1976 is considered to be the founder of cladistics. He proposed a classification system that represented repeated branchings of the family tree, as opposed to the preceding systems, which put organisms on a "ladder", with supposedly more "advanced" organisms at the top.

Taxonomists realise increasingly worked to make the taxonomic system reflect evolution. When it comes to naming, this principle is not always compatible with the traditional rank-based nomenclature in which only taxa associated with a rank can be named because not enough ranks live to name a long series of nested clades. For these and other reasons, phylogenetic nomenclature has been developed; it is for still controversial.

As an example, see the full current classification of this Wikispecies connection and clicking on "Expand".

The name of a clade is conventionally a plural, where the singular referred to regarded and identified separately. unit individually. A unique exception is the reptile clade Dracohors, which was made by haplology from Latin "draco" and "cohors", i.e. "the dragon cohort"; its form with a suffix added should be e.g. "dracohortian".