Selective Breeding

Definition

Selective breeding (artificial selection) = humans intentionally breed plants or animals with desirable characteristics to produce offspring with those traits.

Examples of Selective Breeding

• Domestic dogs → bred for gentle nature.

• Food crops (e.g., wheat) → bred for disease resistance.

• Cows and other livestock → bred to produce more meat or milk.

• Plants (e.g., flowers) → bred for large or unusual flowers.

Process of Selective Breeding

1. Start with a mixed population of the species.

2. Select individuals with desirable traits (e.g., largest male and female cows for meat).

3. Breed the selected individuals together.

4. Offspring show variation; select the best offspring with desired traits.

5. Repeat the process over many generations.

6. Result: population consistently shows the desired traits.

Disadvantages / Risks

• Inbreeding = breeding closely related individuals.

• Can lead to:

  • Increased susceptibility to disease.

  • Inherited defects.

• Example: Some dog breeds develop joint problems, heart disease, or epilepsy due to selective breeding over many generations.

✅ Key Takeaways

• Selective breeding produces desirable traits in plants and animals.

• Process requires repeated selection over generations.

• Inbreeding is a major risk and can harm health.

• Humans have used selective breeding for thousands of years (e.g., wolves → domestic dogs).