Study Notes
Variation and selection involve understanding the differences between individuals of the same species and how these differences can be inherited or influenced by the environment.
- Variation — differences between individuals of the same species. Example: Height differences among humans.
- Phenotypic Variation — differences in physical traits among individuals. Example: Eye color or blood type.
- Genetic Variation — variation caused by differences in genes. Example: Blood group determined by alleles.
- Continuous Variation — variation with a range of small differences. Example: Human height.
- Discontinuous Variation — variation with distinct categories. Example: Blood groups A, B, AB, O.
- Natural Selection — process where organisms better adapted to their environment tend to survive and produce more offspring. Example: Peppered moths during the industrial revolution.
- Artificial Selection — humans select organisms with desirable traits to reproduce. Example: Breeding dogs for specific traits.
Exam Tips
Key Definitions to Remember
- Variation
- Phenotypic Variation
- Genetic Variation
- Continuous Variation
- Discontinuous Variation
- Natural Selection
- Artificial Selection
Common Confusions
- Mixing up continuous and discontinuous variation
- Confusing natural selection with artificial selection
Typical Exam Questions
- What is continuous variation? Continuous variation is when there are many small differences in a trait among individuals.
- How does artificial selection differ from natural selection? Artificial selection is driven by human choice, while natural selection is driven by environmental factors.
- What is an example of discontinuous variation? Blood groups are an example of discontinuous variation.
What Examiners Usually Test
- Understanding of key terms like variation and selection
- Ability to distinguish between continuous and discontinuous variation
- Examples of natural and artificial selection