What is variation? Explain its types and importance.

1. 1 · Define. Variation is the difference in characters among individuals of the same species.
2. 2 · Somatic variation. Occurs in body cells due to food, climate or use; not inherited, e.g. a wrestler's muscles.
3. 3 · Germinal variation. Occurs in gametes; inherited, e.g. eye colour or earlobe type; comes from mixing of genes and from mutation.
4. 4 · Importance.
   • Helps organisms adapt to change.
   • Raw material for evolution.
   • Used by breeders to develop better crops and animals.
5. 5 · Link to daily life. Brothers and sisters look alike but differ; a poorly fed child may be short, but this is not passed on.
6. 6 · Close. So variation, with heredity, explains why offspring are like their parents yet not exactly the same.

Scoring tip: Give one example for each type. Examiners look for the words 'inherited' and 'not inherited'.