This is a lesson I used myself to teach the Adaptation for exchange concept of unit 3 - a level biology, AQA specification. Learning objective: Describe how surface area impacts volume and absorption in organisms and explain why larger organisms need systems in place to combat this. By the end of the lesson learners should be able to: Success criteria: SC1: To calculate surface area: volume ratios. SC2: To describe how SA:V ratios impact larger organisms and how they combat this. SC3: Explain why xerophytes are effective at minimising water loss. Contains past paper questions that target this topic, some questions require knowledge from prior lessons. Powerpoint contains 15 slides and 5 past paper questions.