Dictionary > Punctuated equilibrium

Punctuated equilibrium

Definition
noun
A theory that describes an evolutionary change happening rapidly and in brief geological events in between the long periods of stasis (or equilibrium)
Supplement
Punctuated equilibrium is a theory describing an evolutionary change that occurs rapidly and in brief geological events in between the long periods of stasis (or equilibrium). The theory is based on the stasis in fossil records, and when phenotypic evolution occurs, it is localized in rare, rapid events of branching speciation. Accordingly, the theory assumes that when there is a significant evolutionary change, cladogenesis occurs. Cladogenesis is the process where a species splits into two distinct spcies instead of one species transforming into another over time.1 The American paleontologists Niles Eldredge and Stephen Jay Gould first proposed the theory in 1972. They referred to it as punctuated equilibria.2 This theory is presented to contrast phyletic gradualism. In the latter, evolution is described to happen smoothly and continuously (anagenesis).
Synonym(s):

  • punctuationalism

See also:

  • evolution
  • Reference(s):

    1 Gould, S. J., & Eldredge, N. (1977). “Punctuated equilibria: the tempo and mode of evolution reconsidered.” Paleobiology 3 (2): 115-151.

    2 Eldredge, N. & Gould, S. J. (1972). “Punctuated equilibria: an alternative to phyletic gradualism” In T.J.M. Schopf, ed., Models in Paleobiology. San Francisco: Freeman Cooper. pp. 82-115. Reprinted in N. Eldredge Time frames. Princeton: Princeton Univ. Press, 1985, pp. 193-223.


    You will also like...

    Energy pyramid
    Freshwater Community Energy Relationships – Producers & Consumers

    This tutorial looks at the relationship between organisms. It also explores how energy is passed on in the food chain an..

    Homo Species
    The Homo Species

    The evolution of the species of the genus "Homo" led to the emergence of modern humans. Find out more about human evolut..

    Independent Assortment and Crossing Over
    Independent Assortment and Crossing Over

    This tutorial describes the independent assortment of chromosomes and crossing over as important events in meiosis. Read..

    Growth and Plant Hormones
    Growth and Plant Hormones

    Plants, like animals, produce hormones to regulate plant activities, including growth. They need these hormones to respo..

    Chromosome Mutations
    Chromosome Mutations

    Mutations can also influence the phenotype of an organism. This tutorial looks at the effects of chromosomal mutations, ..

    Carbohydrates, fats and proteins - dietary sources
    A Balanced Diet – Carbohydrates and Fat

    Apart from vitamins, the human body also requires high energy sources such as carbohydrates and fats. If you want an ove..