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
Will there be an opportunity to comment?  In a supplemental notice accompanying the last rule package, EPA is soliciting additional information and public comment on issues fro

what is microbiology

Q. Why is it not correct to assert that the DNA self- replicates? The DNA is not completely self-sufficient in its duplication process because the replication does not occur wi

Q. What kind of exoskeleton do some molluscs present? Some molluscs, like gastropods and bivalves secrete an external calcareous carapace (the shell). Calcium carbonate is a fo

ABA - Dormancy Abscisic acid functions as an antagonist of all three promoters like IAA, GAS and Cytokinins. ABA nullifies the activity of GA, IAA and cytokinin right by a)

Why do substances react with each other? Chemical reactions occur due to the products of the reaction have less energy than the reactants (drive toward less energy). These reac


A flashlight with a 6-volt bulb draws 2 amps from its batteries. What is the resistance of its circuitry?

Define early ebb or shock phase - Physiological Response to injury? This is usually brief in duration lasting 12 to 24 hours and occurs immediately following injury. Blood pres

Q. How you would dispose off sharps and needles? Used needles should not be bent or broken prior to disposal. Unsheathed needles are placed directly into the designated, punctu