Explain what is meant by each of the following terms and describe one example of each: discontinuous variation, continuous variation.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2018). The mark or mark type is shown in brackets.

1. [7] (discontinuous) idea of few + phenotypes / categories AW OR no intermediates ; inherited / passed to next generation ; genes / genetic / genotype / alleles ; correct example (e.g. blood group, eye colour, sex, ear lobes, tongue roll) ; bar chart / bar graph ; (continuous) idea of many + phenotypes / categories AW OR intermediates / range ; genes / genetic / genotype / alleles + environment ; any named environmental factor (e.g. diet / sunlight exposure) ; correct example (e.g. skin colour / hair colour / height / weight) ; normal distribution ;
2. [3] DNA / deoxyribonucleic acid ; chromosomes / genes / alleles ; copied / replicated ; passed to next generation / from parents ; gametes / egg / sperm ;