This topic summary covers Knowledge Organiser within Variation for GCSE Biology. Genetic and environmental variation in organisms It is section 9 of 10 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 9 of 10
Practice
25 questions
Recall
20 flashcards
Knowledge Organiser
Key Terms
- Variation — differences between individuals of same species
- Genetic variation — caused by different alleles/genes
- Environmental variation — caused by living conditions
- Continuous variation — range of values, bell curve
- Discontinuous variation — distinct categories, bar chart
- Mutation — random change in DNA sequence
- Meiosis — cell division producing genetically unique gametes
Examples
- Continuous: height, mass, foot length, IQ score
- Discontinuous: ABO blood group, tongue rolling, sex
- Purely genetic: blood group, inherited disorders
- Purely environmental: scars, language spoken, tanned skin
- Both: height, weight, intelligence
Common Marks Lost
- Saying all variation is inherited — environmental counts
- Saying mutations are always harmful — most are neutral
- Confusing continuous/discontinuous with genetic/environmental
- Not linking variation to natural selection when asked
- Forgetting meiosis as a source of genetic variation (crossing over)