Tuesday, June 08, 2010
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Senior Member
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Join Date: Dec 2009
Location: Pakistan
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Quote:
Originally Posted by iborn2grow
'As-salāmu alaykum
plz guide me what is Polymorphism in zoology? as it was in zoology paper 2009  |
Polymorphism is derived from two words (poly which means many and morph which means shape or form) it occurs when two or more clearly different phenotypes(visible characteristics of organism) exist in the same population of a species — in other words, the occurrence of more than one form or morph. In order to be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating).
Polymorphism is common in nature; it is related to biodiversity, genetic variation and adaptation; it usually functions to retain variety of form in a population living in a varied environment.The most common example is sexual dimorphism, which occurs in many organisms. Other examples are mimetic forms of butterflies, and human haemoglobin and blood types.
Polymorphism results from evolutionary processes, as does any aspect of a species. It is heritable, and is modified by natural selection. In polyphenism, an individual's genetic make-up allows for different morphs, and the switch mechanism that determines which morph is shown is environmental. In genetic polymorphism the genetic make-up determines the morph. Ants exhibit both types in a single population.
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