Question 1: Define selective breeding and explain its main purpose in agriculture.

Answer: Selective breeding is the process of choosing parents with desirable traits to produce offspring with those traits, mainly used to improve crop and livestock qualities.

Question 2: Describe how genetic variation is important for successful selective breeding.

Answer: Genetic variation provides a range of traits within a population, allowing breeders to select the best individuals for desired characteristics.

Question 3: What is meant by 'desirable traits' in the context of selective breeding?

Answer: Traits that are beneficial or preferred, such as higher yield, disease resistance, or faster growth.

Question 1: If a farmer breeds 100 sheep, and 60 of these show the desired trait after one generation, what is the percentage of sheep with the trait? Show your calculation.

Answer: Percentage = (Number with trait / Total number) × 100 = (60 / 100) × 100 = 60%

Question 2: A breeder wants to improve a crop's drought resistance. Out of 200 plants, 80 currently have this trait. What is the proportion of plants with drought resistance? Express as a fraction and percentage.

Answer: Fraction = 80 / 200 = 2 / 5; Percentage = (80 / 200) × 100 = 40%

Question 1: List three variables that must be controlled in a selective breeding experiment to ensure fair results.

Answer: Variables include environmental conditions, age of the plants or animals, and the specific traits being selected for.

Question 2: Describe two safety precautions that should be taken when handling livestock for selective breeding purposes.

Answer: Wearing protective clothing to prevent disease transmission and ensuring proper handling to avoid stress or injury to the animals.

Question 1: A breeder selects the top 10% of plants with the highest fruit size from an initial population of 500 plants. After five generations, the average fruit size has increased by 25%. What does this suggest about the effectiveness of selective breeding in this case?

Answer: It suggests that selective breeding is effective, as it has led to a measurable increase in the desired trait over generations.

Question 1: Explain how selective breeding has been used to develop disease-resistant crops. Include potential advantages and disadvantages.

Answer: Selective breeding involves choosing plants with natural resistance to diseases and breeding them over multiple generations. Advantages include reduced reliance on chemical pesticides and improved crop stability. Disadvantages may include reduced genetic diversity and potential loss of other desirable traits.

Question 2: Identify one ethical consideration related to selective breeding in animals.

Answer: Ethical concerns include the potential for animal suffering, reduced genetic diversity, and the impact on animal welfare.