Speciation (OCR A-level Biology)

This fully-resourced lesson explores the effect of geographical and reproductive isolation on the evolution of a new species. The engaging PowerPoint and accompanying resources have been designed to cover point 6.1.2 (g) of the OCR A-level Biology A specification which states that students should be able to demonstrate and apply an understanding of the effect of these isolating mechanisms on the evolution of a new species by either allopatric or sympatric speciation.

The lesson begins by using the example of a hinny, which is the hybrid offspring of a horse and a donkey, to challenge students to recall the biological classification of a species. Moving forwards, students are introduced to the idea of speciation and the key components of this process, such as isolation and selection pressures, are covered and discussed in detail. Understanding and prior knowledge checks are included throughout the lesson to allow the students to not only assess their progress against the current topic but also to make links to earlier topics in the specification. Time is taken to look at the details of allopatric speciation and how the different mutations that arise in the isolated populations and genetic drift will lead to genetic changes. The example of allopatric speciation in wrasse fish because of the isthmus of Panama is used to allow the students to visualise this process. The final part of the lesson considers sympatric speciation and again a wide variety of tasks are used to enable a deep understanding to be developed.

This lesson has been written to tie in with the other uploaded lessons on topic 6.1.2 (patterns of inheritance).