Investigating diversity (AQA A-level Biology)

This lesson describes how genetic diversity within, or between species, can be investigated by comparison of characteristics or biological molecules. The PowerPoint and accompanying worksheets are primarily designed to cover the content of point 4.7 of the AQA A-level Biology specification but as this is the last lesson in the topic, it has also been planned to contain a range of questions, tasks and quiz rounds that will challenge the students on their knowledge and understanding of topic 4.

Over the course of the lesson, the students will discover that comparisons of measurable or observable characteristics, DNA and mRNA sequences and the primary structure of common proteins can all be used to investigate diversity. Links are continually made to prior learning, such as the existence of convergent evolution as evidence of the need to compare biological molecules as opposed to the simple comparison of phenotypes. The issues associated with a limited genetic diversity are discussed and the interesting biological example of the congenital dysfunctions consistently found in the Sumatran tigers in captivity in Australia and New Zealand is used to demonstrate the problems of a small gene pool. Moving forwards, the study of the 16S ribosomal RNA gene by Carl Woese is introduced and students will learn that this led to the adoption of the three-domain system in 1990. The final part of the lesson describes how the primary structure of proteins like cytochrome c that is involved in respiration and is therefore found in most living organisms can be compared and challenges the students to demonstrate their understanding of protein synthesis when considering the differences between humans and rhesus monkeys.