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heterochrony
heterochrony Any change in the relative rates or timing of development of different cell lines in the body. Such changes can lead to significant alterations in form; for example, if a particular organ develops earlier or faster it may be larger. Hence, mutations causing such changes play an important role in evolution. Heterochronic changes affecting the relative rates of development of germ (reproductive) cells and somatic (body) cells are of particular interest. They fall into four categories – acceleration, progenesis, neoteny, and hypermorphosis – depending on whether the change in rate (speeded up or slowed down) affects the somatic tissues or the reproductive tissues (see table). However, they have only two possible outcomes: one is paedomorphosis, in which reproduction occurs in an ancestrally juvenile form; the other is peramorphosis, in which development is extended by the addition of stages to the sequence shown in the ancestral form.
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"heterochrony." A Dictionary of Biology. 2004. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "heterochrony." A Dictionary of Biology. 2004. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O6-heterochrony.html "heterochrony." A Dictionary of Biology. 2004. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-heterochrony.html |
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heterochrony
heterochrony The dissociation in time of the development of factors such as shape, size, and maturity, so that organisms mature in these respects either at earlier stages of growth (e.g. in acceleration, predisplacement, and hypermorphosis) or in later stages (e.g. in neoteny, progenesis, and postdisplacement). This can lead in turn to paedomorphosis or peramorphosis (recapitulation of phylogeny).
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MICHAEL ALLABY. "heterochrony." A Dictionary of Ecology. 2004. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "heterochrony." A Dictionary of Ecology. 2004. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O14-heterochrony.html MICHAEL ALLABY. "heterochrony." A Dictionary of Ecology. 2004. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-heterochrony.html |
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heterochrony
heterochrony The dissociation, during development, of factors of shape, size, and maturity, so that organisms mature in these respects at earlier or later growth stages. This leads to paedomorphosis or recapitulation (peramorphosis). Compare HETEROTOPY.
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MICHAEL ALLABY. "heterochrony." A Dictionary of Zoology. 1999. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "heterochrony." A Dictionary of Zoology. 1999. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O8-heterochrony.html MICHAEL ALLABY. "heterochrony." A Dictionary of Zoology. 1999. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O8-heterochrony.html |
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heterochrony
heterochrony Dissociation, during development, of factors of shape, size, and maturity, so that organisms mature in these respects at earlier or later growth stages. This leads to either paedomorphosis or recapitulation.
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AILSA ALLABY and MICHAEL ALLABY. "heterochrony." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "heterochrony." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O13-heterochrony.html AILSA ALLABY and MICHAEL ALLABY. "heterochrony." A Dictionary of Earth Sciences. 1999. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-heterochrony.html |
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heterochrony
heterochrony The dissociation, during the development of factors of shape, size, and maturity, so that organisms mature in these respects at earlier or later growth stages.
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Cite this article
MICHAEL ALLABY. "heterochrony." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "heterochrony." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O7-heterochrony.html MICHAEL ALLABY. "heterochrony." A Dictionary of Plant Sciences. 1998. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-heterochrony.html |
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