Adaptations & natural selection (OCR A-level Biology)

This fully-resourced lesson describes how the mechanism of natural selection results in changes in a population that are known as adaptations. The PowerPoint and accompanying resources have been designed to cover specification points 4.2.2 (g), (h) and (i) as detailed in the OCR A-level Biology A specification and also considers how antibiotic resistance has implications for human populations.

President Trump’s error ridden speech about antibiotics is used at the beginning of the lesson to remind students that this is a treatment for bacterial infections and not viruses as he stated. Moving forwards, 2 quick quiz competitions are used to introduce MRSA and then to get the students to recognise that they can use this abbreviation as a reminder to use mutation, reproduce, selection (and survive) and allele in their descriptions of evolution through natural selection. The main task of the lesson challenges the students to form a description that explains how this strain of bacteria developed resistance to methicillin to enable them to see the principles of natural selection. This can then be used when describing how the anatomy of the modern-day giraffe has evolved over time. The concept of convergent evolution is introduced and links are made to the need for modern classification techniques which was considered in the previous sub-module. Moving forwards, students will understand how natural selection leads to adaptations and a quick quiz competition introduces the different types of adaptation and a series of tasks are used to ensure that the students can distinguish between anatomical, behavioural and physiological adaptations. The Marram grass is used to test their understanding further, before a step by step guide describes how the lignified cells prevent a loss of turgidity. Moving forwards, the students are challenged to explain how the other adaptations of this grass help it to survive in its environment. A series of exam-style questions on the Mangrove family will challenge them to make links to other topics such as osmosis and the mark schemes are displayed to allow them to assess their understanding. The final part of the lesson focuses on the adaptations of the anteater and again current understanding of this topic is tested alongside prior knowledge of classification hierarchy.

Due to the extensiveness of this lesson and the detail contained within the resources, it is estimated that it will take in excess of 2/3 hours of allocated A-level teaching time to deliver this lesson.