Primary succession (OCR A-level biology)

This lesson describes succession as the gradual, progressive changes in a ecosystem, moving from colonisation by the pioneer species to a climax community. The detailed PowerPoint and accompanying resources have been designed to cover point 6.3.1 (d) of the OCR A-level Biology specification, and therefore the lesson also describes deflected succession and the formation of a plagioclimax community.

As shown in the cover image, the lesson uses a step by step guide to describe primary succession, introducing the different species at each stage, and explaining the vital roles they each perform. Time is taken to explain how the initial colonisation by algae and lichens as pioneer species is critical to form soil, which wasn’t previously present on the bare ground. The real-world example of Surtsey is used to increase relevance and students will hear about the changes that have occurred on this island over the last 67 years. Understanding checks are included at regular points to allow the students to assess their progress, and prior knowledge checks challenge them to recall content from earlier modules. Answers to all of the checks are embedded in the PowerPoint.

The final part of the lesson considers how many ecosystems are prevented from reaching their climax community and this is known as deflected succession. Human influences are explored and again, real examples are used.