The Impact and Problems of Selective Breeding Revision Notes | GCSE OCR Foundation Biology

What this lesson covers

Explore the benefits and drawbacks of selective breeding, including its impact on food production and the problems of inbreeding in domesticated animals.

• Explain the impact of selective breeding on food plants and domesticated animals
• Evaluate the benefits and problems of selective breeding programmes
• Describe how inbreeding can lead to increased susceptibility to disease
• Compare the advantages and disadvantages of selective breeding in agriculture

Key ideas to keep in view

Use this lesson to stay inside B5.2 Natural selection and evolution while connecting the detail back to the wider B5: Genes, inheritance and selection topic.

• B5: Genes, inheritance and selection
• B5.2 Natural selection and evolution
• GCSE OCR Foundation Biology

Lesson notes preview

Read the core explanations from The Impact and Problems of Selective Breeding before testing yourself from memory.

• 1. The Power and Price of Selective Breeding
• Farmers have been shaping life for thousands of years. That tiny chihuahua and massive Great Dane? Both descended from wolves through selective breeding. Your breakfast cereal? Those wheat grains are three times larger than their wild ancestors. But this power comes with hidden costs that can threaten entire breeds.
• The process of choosing organisms with desirable characteristics to breed together to produce offspring with those traits. Also called artificial selection.
• Think of selective breeding as nature's editing tool in human hands. Instead of random mating, we choose the 'best' individuals as parents. The fastest horses breed with other fast horses. The juiciest tomatoes produce seeds for next year's crop.
• Selective breeding has transformed our food supply and created remarkable animals. Modern dairy cows produce 6-7 times more milk than their ancestors. Wheat yields have tripled since the 1960s. Chickens grow to market weight in half the time they used to.
• Food plants benefit enormously: Larger fruits and vegetables, disease resistance, longer shelf life, and crops that ripen at the same time for easier harvesting. Corn cobs have grown from thumb-sized to today's massive ears through centuries of selective breeding.
• Domesticated animals show dramatic changes: Sheep produce more wool, pigs grow leaner meat, and dogs have been shaped into hundreds of breeds for specific jobs - from herding sheep to detecting explosives.
• 3. The Dark Side: Problems with Selective Breeding
• Here's where selective breeding gets dangerous. When we choose only the 'best' individuals to breed, we're actually throwing away genetic variation. It's like editing a book by removing most of the words - eventually, you can't tell the full story anymore.
• Breeding between closely related organisms, which reduces genetic variation and can increase the risk of inherited defects and disease susceptibility.

Continue through the topic

Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.