The document explains the concepts of natural selection and selective breeding, detailing how traits that enhance survival become more common in a population through natural processes versus human intervention. It highlights key elements of natural selection like genetic variation and competition, and illustrates these concepts with examples such as beetle coloration and antibiotic resistance in bacteria. Additionally, the document contrasts natural selection and selective breeding, noting their differences in terms of process, purpose, and impact on biodiversity.

1. Natural Selection and Selective Breeding: Understanding
Evolutionary Processes

2. Introduction to Natural
Selection
● Natural selection is a process where
certain traits become more common in a
population over time
● These traits help organisms survive and
reproduce better in their environment
● Involves genetic variation, production of
many offspring, and struggle for survival
● How do you think natural selection might
affect a population over many
generations?

3. Key Elements of Natural Selection
● Genetic variation within a population
● Production of many offspring
● Competition for resources and survival
● Better adapted individuals have higher chance of reproducing
● Advantageous traits are passed on to next generations
● What might be an example of an advantageous trait in your local
environment?

4. Example: Natural
Selection in Beetles
● Population of beetles with variation in
color (green and brown)
● Brown beetles have better camouflage on
tree bark
● Predators easily spot green beetles
● Brown beetles more likely to survive and
reproduce
● Over time, proportion of brown beetles
increases in population
● Can you think of other examples where
camouflage provides an advantage?

5. Adaptation through Natural Selection
● Adaptation: Process by which populations become more suited
to their environment
● Results from natural selection over many generations
● Helps organisms survive and thrive in specific environments
● What adaptations have you observed in local wildlife?

6. Antibiotic Resistance:
Natural Selection in Action
● Some bacteria have genetic mutations
making them resistant to antibiotics
● When antibiotics are used, resistant
bacteria survive and reproduce
● Leads to large populations of resistant
bacteria
● Antibiotics become ineffective over time
● How might this impact human health and
medicine?

7. Introduction to Selective Breeding
● Also known as artificial selection
● Process where humans choose individuals with desirable
features to breed
● Selected individuals produce next generation
● Offspring with desired features are chosen for further breeding
● How is this different from natural selection?

8. Selective Breeding in
Plants
● Enhances traits like disease resistance,
crop yield, and flavor
● Improves adaptation to challenging
weather conditions
● Develops plants with unique or large
flowers
● Can you name a fruit or vegetable that
has been selectively bred?

9. Example: Breeding Disease-Resistant Crops
● Identify plants with disease resistance
● Cross-breed resistant plants
● Select offspring with increased resistance
● Continue breeding and selection over generations
● Develop new, more resilient varieties
● What might be the potential drawbacks of this process?

10. Selective Breeding in
Animals
● Develops specific traits over multiple
generations
● Examples: High milk-producing cows,
chickens laying large eggs
● Creates domestic dogs with specific
characteristics
● Produces sheep with high-quality wool
● Breeds horses for speed and fine features
● Can you think of an animal breed
developed for a specific purpose?

11. Natural vs. Artificial Selection: Key Differences
● Natural selection occurs without human intervention; artificial
selection is human-driven
● Natural selection enhances survival in specific environments;
artificial selection focuses on human-desired traits
● Natural selection typically occurs over long periods; artificial
selection can produce rapid changes
● How might artificial selection impact biodiversity? Discuss
potential pros and cons.