Summary
Inheritance involves the transmission of genetic information from one generation to the next, with changes occurring due to mutations and variations.
- Mutation — a spontaneous change in the structure of a gene or chromosome. Example: Sickle cell anemia is caused by a gene mutation, while Down Syndrome is caused by a chromosome mutation.
- Variation — differences between individuals of the same species, which can be continuous or discontinuous. Example: Continuous variation includes traits like height, while discontinuous variation includes traits like blood groups.
- Natural Selection — the process where organisms better adapted to their environment tend to survive and produce more offspring. Example: A bird of prey with sharper vision is more likely to find a meal.
- Artificial Selection — humans select organisms with desirable traits to breed. Example: Breeding soybeans for higher oil content.
Exam Tips
Key Definitions to Remember
- Mutation
- Variation
- Natural Selection
- Artificial Selection
Common Confusions
- Confusing continuous and discontinuous variation
- Misunderstanding the role of the environment in natural vs. artificial selection
Typical Exam Questions
- What are some causes of variation? Environmental factors and genetic mutations
- Why are sickle cell anemia and Down’s syndrome considered mutations? They result from changes in genes and chromosomes
What Examiners Usually Test
- Understanding of mutation types and examples
- Differences between continuous and discontinuous variation
- The process and implications of natural and artificial selection
