extinction

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extinction

 [eks-ting´shun]
in psychology, the disappearance of a conditioned response as a result of its not being reinforced; also, the process by which the disappearance is accomplished. See also conditioning.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ex·tinc·tion

(eks-tingk'shŭn),
1. In behavior modification or in classical or operant conditioning, a progressive decrease in the frequency of a response that is not positively reinforced; the withdrawal of reinforcers known to maintain an undesirable behavior.
2. Synonym(s): absorbance
[L. extinguo, to quench]
Farlex Partner Medical Dictionary © Farlex 2012

extinction

(ĭk-stĭngk′shən)
n.
1.
a. The act of extinguishing: The extinction of the fire took several hours.
b. The condition of being extinguished: mourned the extinction of her dreams.
2. The fact of being extinct or the process of becoming extinct: the extinction of the passenger pigeon; languages that are in danger of extinction.
3. Psychology A reduction or a loss in the strength or rate of a conditioned response when the unconditioned stimulus or reinforcement is withheld.
4. Physiology A gradual decrease in the excitability of a nerve to a previously adequate stimulus, usually resulting in total loss of excitability.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

extinction

Psychiatry A facet of operant–classical conditioning, in which the conditioned response is weakened and eventually disappears by nonreinforcement. See Operant conditioning, Respondent conditioning, Sensory extinction.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

ex·tinc·tion

(eks-tingk'shŭn)
1. In behavior modification or classical or operant conditioning, a progressive decrease in the frequency of a response that is not positively reinforced.
See: conditioning
2. Synonym(s): absorbance.
[L. extinguo, to quench]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

extinction

  1. the act of making EXTINCT or the state of being extinct.
  2. the elimination of an allele of a gene in a population, due to RANDOM GENETIC DRIFT or to adverse SELECTION pressures.
  3. any periodical, catastrophic event resulting in a species or larger taxonomic group dying out abruptly at a particular point in geological history. Such extinctions are thought to be cyclical, occurring every 28.4 million years, and have been attributed to cosmic activity such as showers of large asteroids or comets, though neither the periodicity nor its causes are at present universally accepted.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
Even though the thylacine enhancer seems to work the same as the mouse enhancer, mice and marsupials are so different that sometimes enhancers in mice might misbehave, giving researchers the wrong impression about how such bits of DNA worked in the extinct animals, comments Carles Lalueza-Fox, a paleogeneticist at the University of Barcelona.
Read: (http://www.ibtimes.com/fossils-africa-are-new-extinct-species-distantly-related-cats-dogs-2528107) The Extinct Animal Distantly Related to Cats and Dogs
The codes for extinct animals were thought to have died along with them, until recently, when machines like one at the Smithsonian's DNA lab started working magic.
Experts at the Roslin laboratory - which cloned Dolly the sheep in 1996 - said the chances of successfully cloning an extinct animal using a rare whole cell were 1,000:1 against.
It is the first time an extinct animal has been cloned.
Whereas some thought the comblike pieces belonged to ancient mollusks, others saw them as fossilized algae or plants, and many more suggested that conodonts represent teeth from some type of unknown, extinct animal.
Scientists have discovered many extinct animals, including the oldest known bee and a feathered dinosaur tail, in amber from this valley.
Extinct animals shot and brought to the UK as trophies include the scimitar-horned oryx, and the Arabian Oryx, which was hunted to extinction in the wild in 1972.
The greatest historic treasures are concealed in the dense, green Shada Mountain, where there are caves containing engraved drawings and inscriptions dating back almost 3,000 years, including pictures of extinct animals. The area includes two mountains, Shada Al-Asfal (Lower Shada) and Shada Al-Ala (Higher Shada), which rise to a height of 1,700 meters above the sea level and provide some beautiful scenery.
Transforming an educational presentation into a playful and interactive exhibition, viewers can learn about the harsh living conditions of the people of that time and their battle against wild animals, discover the wonders of extinct animals and come very close to touching the coat of a mammoth, a saber tooth tiger, a smilodon, a majestic tiger and the giant beaver.