Lecture on Artificial Selection and Ethical Considerations

Introduction to Polymorphic Populations

• Polymorphism: Populations can have more than one gene determining the phenotype.
• Wild Type: The original or most common characteristic.
• Mutagens: Differentiations from the wild type.

Artificial Selection

• Definition: Selecting plants or animals with desirable characteristics to breed together.
• Examples:
  • Breeding a bull with large muscle mass with a high milk-yielding cow.
  • Producing seeds with specific traits.
• Key Terms:
  • Selection Pressure
  • Breeding over many generations
  • Desired Characteristics

Detailed Example of Dairy Cows

• Selection Pressure: Large milk yield, good quality milk, large udders.
• Process:
  1. Select a cow with a high milk yield and a bull with females in its lineage with large udders.
  2. Breed them together.
  3. From the offspring, select those with the desired traits.
  4. Breed these offspring with others having similar traits.
  5. Over generations, the desired traits become dominant.

Historical Examples of Artificial Selection

• Pugs:
  • 1880s: Looked different.
  • Present: Issues with narrow nasal cavities, overheating, high blood pressure.
• Wheat:
  • Wild type vs. domesticated varieties.
  • Selected for higher yield but can have disadvantages like heavy heads.
• Chickens:
  • Selected for increased muscle mass, but this can affect their cardiac muscle and overall health.
• Bulls:
  • Selected for large muscle mass, leading to restricted movements and potential heart issues.
• Wild Mustard Products:
  • Different products (e.g., cauliflower) selected for specific traits.
  • Can result in disadvantages like abnormal leaf formation affecting photosynthesis.
• Dash Hounds:
  • Long, thin bodies leading to issues with back, legs, and mobility.
• Bulldogs:
  • Another example of selective breeding leading to physical issues.

Ethical Considerations of Artificial Selection

• Subjective Nature: Ethical considerations are subjective and can vary.
• Mat Scheme: Be aware of points directly from the mat scheme.
• Important Ethical Points:
  • Can include welfare of animals, health issues, environmental impact, etc.

Conclusion

• Summary: Overview of selective breeding, artificial selection, and associated ethical considerations.
• Exam Tip: Focus on understanding the definitions, processes, examples, and ethical implications for exams.