A description of Mendel's work with pea plants to demonstrate dominant and recessive inheritance. Between 1856 and 1863, Gregor Mendel bred over 30,000 different plants, crossbreeding those with distinctive characteristics. Crossing pink and white-flowered pea plants produced all pink flowers in the first generation. However, in the second generation, the ratio of pink to white flowers was 3:1. This indicated that producing white flowers was a recessive characteristic masked by the dominant characteristic of the pink flower.
Show this clip as stimulus material before giving the students a worked example of a monohybrid genetic cross using a Punnett square diagram. Follow this up with further genetic crosses that they could work out the potential offspring for. Assessment of learning can then be done with past paper questions. Students could work out calculations on the probabilities of different generations of offspring developing different characteristics.