VARIATIONS -

1. Defined as "dissimilarities of features among members of the same species".
2. Offsprings of same parent are different and also differ from their parent.
3. This is due to sexual reproduction variation occuring at gene level and are inheritable hence are the raw material for evolution.
4. The genetic constitution which governs such traits is called genotype.
5. Phenotype is the physical expression of genes of an organism.
6. Natural selection can act upon genetic variation only when it is expressed in the phenotype.