Summary and Exam Tips for Selective Breeding
Selective Breeding is a subtopic of Use of Biological Resources, which falls under the subject Biology in the Edexcel IGCSE curriculum. Selective breeding, also known as artificial selection, is a process where humans select organisms with desirable traits to reproduce, enhancing specific characteristics over generations. Unlike natural selection, where environmental pressures determine survival, humans actively choose traits to improve agricultural and livestock productivity. For instance, farmers may select tomato plants that produce larger fruits, ensuring future generations inherit these traits. Similarly, animals like chickens are bred for increased size and meat yield, resulting in modern chickens being significantly larger than their ancestors.
Selective breeding is applied to both plants and animals, aiming to develop traits such as disease resistance, increased yield, and improved taste in plants, or higher milk and meat production in animals. A notable example is the wild brassica, selectively bred to produce various vegetables like cauliflower and broccoli. In animals, selective breeding has been practiced for thousands of years, with domestic dogs being a prime example, all breeds descending from wolves. This method is economically beneficial, maximizing output and efficiency.
Exam Tips
- Use precise terminology: Always incorporate key biological terms in your answers to demonstrate understanding.
- Understand the question: Differentiate between 'what' and 'why' questions to provide accurate responses.
- Be concise and relevant: The number of marks indicates the depth of detail required in your answer.
- Avoid vague language: Words like "it" or "they" should be clearly defined to avoid ambiguity.
- Practice with examples: Use examples like the selective breeding of tomatoes or chickens to illustrate your points effectively.
