Clade

A clade (from Ancient Greek: κλάδος, klados, "branch") is a group of organisms that consists of a common ancestor and all its lineal descendants, and represents a single "branch" on the "tree of life".

The common ancestor may be an individual, a population, a species (extinct or extant), and so on right up to a kingdom. Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently.

Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic.

Etymology

The term "clade" was coined in 1957 by the biologist Julian Huxley to refer to the result of cladogenesis, a concept Huxley borrowed from Bernhard Rensch.

Many commonly named groups are clades, for example, rodents, or insects; because in each case, their name comprises a common ancestor with all its descendant branches. Rodents, for example, are a branch of mammals that split off after the end of the period when the clade Dinosauria stopped being the dominant terrestrial vertebrates 66 million years ago. The original population and all its descendants are a clade. The rodent clade corresponds to the order Rodentia, and insects to the class Insecta. These clades include smaller clades, such as chipmunk or ant, each of which comprises even smaller clades. The clade "rodent" is in turn included in the mammal, vertebrate and animal clades.

Clade (novel)

Clade is a science fiction novel written by Mark Budz, published in 2003. In Clade, an environmental disaster called the Ecocaust has caused sea levels to rise and causing additional strains on human resources. The government, in response, becomes more restrictive on human freedoms, and this novel explores what happens after the Ecocaust.

Plot summary

In Clade, the Ecocaust, an environmental disaster, causes major problems such as rising sea levels and additional strains on human resources. Although civilization recovers from this disaster, they do so at the expense of their previous freedoms. "Polycorps" develop from governments and corporations. The wonders of biotech introduce a new class system where human beings have been socially engineered at the molecular level through a process called "clading." This "clading" process places entire socioeconomic or ethnic groups made to be biologically predisposed to live in particular communities. If a person enters a community that they have not been claded to, the consequences could be devastating, resulting in sickness or death. Although it is not intentionally racist, businesses and retail outlets using this clading process to keep away the riffraff, will simply screen out clientele below a certain prosperity level. Therefore, a black market exists enabling people to buy the right biotech to inhibit the "pherions" in their systems to be placed in a certain clade.

Clade (disambiguation)

Clade is a phylogenetic group.

Clade may also refer to:

See also