Study Notes
Genetic mutations are changes in a gene or chromosome that can have various effects on an organism. They occur randomly but can be influenced by factors like ionising radiation.
- Variation — differences between individuals of the same species Example: Height differences among humans
- Phenotypic Variation — differences in features between individuals Example: Eye color variations
- Genetic Variation — differences caused by genes Example: Blood group types
- Continuous Variation — a range of phenotypes between two extremes Example: Human height
- Discontinuous Variation — distinct phenotypes with no intermediates Example: Blood groups A, B, AB, and O
- Mutation — a change in a gene or chromosome Example: Sickle cell anemia caused by a genetic mutation
Exam Tips
Key Definitions to Remember
- Variation: Differences between individuals of the same species
- Mutation: A change in a gene or chromosome
- Continuous Variation: Range of phenotypes between two extremes
- Discontinuous Variation: Distinct phenotypes with no intermediates
Common Confusions
- Confusing continuous with discontinuous variation
- Believing all mutations are harmful
Typical Exam Questions
- What is a mutation? A change in a gene or chromosome
- How does ionising radiation affect mutation rates? It increases the rate of mutations
- What is an example of continuous variation? Human height
What Examiners Usually Test
- Understanding of the difference between continuous and discontinuous variation
- Effects of mutations on organisms
- Causes and examples of genetic and environmental variation