Types of variations, Biology

Types of Variations -

Somatogenic and Blastogenic Variation

  • Changes in somatic parts of the body are somatic variations e.g. wrestler's muscle, circumcised penis of muslims, etc., not inheritable, hence have no role in evolution.
  • Blastogenic variations are the changes at germinal cell level or in the genotype or gene patterns, these are inheritable and hence form the basis for evolution.

2.       Continuous and Discountinuous Variation

  • Continuous variations are small, gradual changes e.g. changes in color, size, shape, body weight etc.
  • The discontinuous variation are the discrete and sudden, without any intermediate stage or gradations.
  • This is qualitative (substantive) when related to color, shape and size e.g., Ancon sheep in Seth Wright's farm quantitative (meristic) when related to the number of parts e.g. - hexadactyli, single kidney, single horn etc.

3.       Determinate and Indeterminate variation

  • Determinate variation are adaptive, selective and of definite evolutionary line, also called as orthogenic variation; controlled by strong genes, sometimes, it may become deleterious beyond the limit of its usefulness.
  • Indeterminate variations have no evolutionary line, it is sudden and nondirectional.
Posted Date: 10/9/2012 1:37:02 AM | Location : United States







Related Discussions:- Types of variations, Assignment Help, Ask Question on Types of variations, Get Answer, Expert's Help, Types of variations Discussions

Write discussion on Types of variations
Your posts are moderated
Related Questions
2 phases of oogenesis

Transmission electron microscopy: Around 1931-32 two German scientists. Knoll and Ruska. Invented transmission electron microscopy, and built the first transmission electron m

Periimplant Probing Depth In contrast to natural teeth, for which the average periodontal probing depth (PD) has been reported, the physiologic depth of the periimplant sulcus

What are the main representatives of the pteridophytes? Is this plant group cryptogamic or phanerogamic? The better known pteridophytes are the ferns and the maidenhairs, from

Explain about the Observation and Classification of Arthropoda? Introduction In the previous unit you have examined the representatives of artliropoda.  In this unit, you wi

Amantadine Treatment with oral amantadine or rimantadine begun within 48 hours after the onset of illness decreases the duration of fever and symptoms by about 1 day. Whether t

In Reggie's case, he fractured the proximal end of his right femur, an integral component of his hip. Name the joint disorders that Reggie is more a risk of in (a) the short term a

PHYLUM ANNELIDA Definition  and Introduction Bilateral and  protosomial  eucoelomate  eumetazoans  whose  long   narrow and  wormlike body  is division  into  ring like  t

briefly explain filter feeding in holozoicanimals

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4