Worksheets and lesson ideas to challenge students aged 11 to 16 to think hard about selective breeding (GCSE and Key Stage 3)
Selective breeding can be an excellent way for students to develop their understanding of evolution as artificial selection by humans is perhaps easier to think about than natural selection in the wild. The key ideas involved in understanding selective breeding are:
- Variation in the population – some of this is inherited
- A specific trait is selected for and individuals with these traits are bred together
- Offspring with the desired characteristic are then bred together and the process is repeated over hundreds of generations
- When all the offspring show the desired characteristic then the trait has been selective bred
- Because the farmer, or herder, does the selection certain traits needed for survival in the wild may begin to be lost
Where to start?
Show students an image of an animal before domestication. Ask students what traits they would want to select for? The video below provides an excellent introduction to domestication, which was a precursor to selective breeding and so helps set the scene.
Selective breeding sheep for wool
Sheep were one of the first animals to be domesticated by humans around 10,500 years ago. Wild sheep used to lose their wool through moulting which was problematic for herders as valuable wool was strewn around the ground that had to be picked up. However, through selective breeding, farmers have bred sheep to produce thicker wool that can be shorn off every year, allowing farmers to produce a fleece for sale.
- What are the ethical implications of selective breeding for thicker wool in sheep?
- Why haven’t sheep been selected to produce thick woollen coats that moult once a year?
- What are the potential problems of selective breeding?