The role of genes in controlling inherited characteristics is described. The terms dominant and recessive are defined. Eye colour is used as an example and the combination of two recessive genes is used to explain how people can have blue eyes.
Ask student to bring in family photos and discuss in class the inherited features that can be seen. Students should attempt to explain inheritance in terms of genetic information. The idea of dominant and recessive genes can be discussed in relation to features that can be seen to skip generations, or which are inherited by some children but not others. The class could investigate a variety of discrete and continuous characteristics including eye colour, height and tongue-rolling and describe these in terms of single gene and polygenic inheritance. Relate inheritance and variation and encourage students to explain how they can relate to the size of a population’s gene pool.