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  1. Morphological variations
  2. Physiological variation
  3. Application of variation



Evolution is the cumulative changes in the characteristics of population or organisms occurring in the course of successive generations related by descent. Variations are differences in traits or characteristics between individuals of the same species.

Variation can be:

(i) Discontinuous or

(ii) Continuous

(i) In Discontinuous variation, individuals fall into distinct categories e.g. Pea plant with either red flowers or white flowers. There are no intermediate forms between these traits. They are easily distinguishable and are not affected by environmental conditions.

Examples of such traits are

(i) The ability to roll the tongue

(ii) Taste phenylthiocarbamide (PTB),

(iii) ABO blood groups in man and

(iv) Normal and vestigial wings in Drosophila.

Such discontinuous variation is brought about by one or a few genes.

(ii) In Continuous variation, there is a complete range of measurements from one extreme to another.

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