1. Discontinuous and Continuous Variation

5. Modified by environmental conditions, e.g. greater exposure of the skin to sunlight will produce a darker skin colour Not modified by environmental changes Genes show additive effect , e.g. the more ‘dark’ genes, the darker will be the skin colour Genes do not show additive effect Controlled by many genes Controlled by a few genes Deals with a spectrum of phenotypes , ranging from one extreme to the other Deals with a few clear-cut phenotypes Continuous Variation Discontinuous Variation

6. Artificial selection

8. Examples of artificial selection

9. Examples of artificial selection