Nearby Words
noun Biology.
the response, as affecting growth or reproduction, of an organism to the length of exposure to light in a 24-hour period.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2012.
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Based on the Random House Dictionary, © Random House, Inc. 2012.
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Link To photoperiodism
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Photoperiodism
is always a great word to know.
So is orthogenesis. Does it mean:
| a theory that evolution of a species is due to a predetermined series of alterations intrinsic to the species, not due to natural selection |
| an organism that is not adapted to prevailing conditions or producing offspring that maintain its contribution of genes to the next generation |
Collins
Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
American Heritage
Medical Dictionary
photoperiodism pho·to·pe·ri·od·ism (fō'tō-pĭr'ē-ə-dĭz'əm) or pho·to·pe·ri·o·dic·i·ty (-pĭr'ē-ə-dĭs'ĭ-tē)
n.
The response of an organism to changes in its photoperiod, especially as indicated by vital processes.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
photoperiodism (fō'tō-pîr'ē-ə-dĭz'əm) also photoperiodicity  (fō'tō-pîr'ē-ə-dĭz'əm) Pronunciation Key
The response of an organism to changes in its photoperiod, especially as indicated by vital processes. For example, many plants exhibit photoperiodism by flowering only after being exposed to a set amount of daylight, as by requiring either a long or short day to flower. Plant growth, seed germination, and fruiting are also affected by day length. Photoperiodic responses in plants are regulated by special pigments known as phytochromes. In animals, migration, mating, amount of sleep, and other behaviors are also photoperiodic. In many animals, photoperiodism is regulated by the hormone melatonin. |
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
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