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effect hypothesis

effect hypothesis A model proposed in 1980 by the palaeontologist Elisabeth Vrba to account for evolutionary trends. She proposed that a species, occupying a restricted ecological niche, would continually give rise to daughter species by punctuated equilibrium. These new species would have a variety of characteristics, but because of the features of the particular ecological niche, only species that possessed a particular suite of characters would survive. The surviving species would speciate in their turn, with the same result, and at each level the lineage appears to be ‘pushed’ further and further in a given direction. Compare directed speciation.

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effect hypothesis

effect hypothesis A model proposed in 1980 by the palaeontologist Elisabeth Vrba to account for evolutionary trends. She proposed that a species, occupying a restricted ecological niche, would continually give rise to daughter species by punctuated equilibrium. These new species would have a variety of characteristics; but because of the features of the particular ecological niche, only species that possessed a particular suite of characters would survive; the surviving species would speciate in their turn, with the same result, and at each level the lineage appears to be ‘pushed’ further and further in a given direction.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
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"effect hypothesis." A Dictionary of Zoology. . Encyclopedia.com. 16 Nov. 2018 <https://www.encyclopedia.com>.

"effect hypothesis." A Dictionary of Zoology. . Encyclopedia.com. (November 16, 2018). https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/effect-hypothesis-0

"effect hypothesis." A Dictionary of Zoology. . Retrieved November 16, 2018 from Encyclopedia.com: https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/effect-hypothesis-0

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

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The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.