AskDefine | Define derived

Dictionary Definition

derived adj
1 determined by mathematical computation; "the calculated velocity of a bullet"; "a derived value" [syn: calculated]
2 formed or developed from something else; not original; "the belief that classes and organizations are secondary and derived"- John Dewey [ant: underived]

User Contributed Dictionary

English

Pronunciation

Adjective

  1. Of, or pertaining to, conditions unique to the descendant species of a clade, and not found in earlier ancestral species.
  2. In the context of "systematics|comparable|archaic": Possessing features believed to be more advanced or improved than those other organisms.
  3. product of derivation

Translations

Of conditions unique to the descendant species
Possessing features believed to be advanced
product of deriving

See also

Verb form

derived
  1. past tense and participle of derive.

Extensive Definition

In phylogenetics, a trait is derived if it is present in an organism, but was absent in the last common ancestor of the group being considered.
For the sake of precision, the term "derived" is preferred to "advanced," a term which may inaccurately imply superiority. Simplicity is often secondarily derived - for example, the absence of leaves in the whisk fern Psilotum is a result of their secondary loss, and when considered in the context of ferns as a whole, is a derived trait. Likewise, the primitive character state for birds (i.e. the state possessed by their last common ancestor) is flight, which was secondarily lost by penguins and dodos.
Whether or not a trait is considered derived depends on the group in question. For example, Among the tetrapods, having five fingers is the primitive trait - as their last common ancestor bore a five-digit hand. However, amongst the vertebrates, five fingers is a derived trait, as the last common ancestor to the vertebrates did not even bear fingers.

References

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