This key facts covers Sources of Genetic Variation within Variation for GCSE Biology. Genetic and environmental variation in organisms It is section 2 of 10 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Sources of Genetic Variation

Mutations: Random changes in DNA sequence
Sexual reproduction: Mixing of alleles from two parents
Meiosis: Random assortment of chromosomes; crossing over

Practice questions for Variation

What is the main difference between genetic variation and environmental variation?

A. Genetic variation is caused by differences in DNA, environmental variation is caused by external factors
B. Genetic variation affects all organisms equally, environmental variation affects each organism differently
C. Genetic variation is reversible, environmental variation is permanent
D. Genetic variation only affects physical traits, environmental variation only affects behavioral traits

1 markfoundation

Explain how mutations contribute to genetic variation in populations.

4 marksstandard

Quick recall flashcards

What are the two main causes of genetic variation?

1. Mutations — random changes to DNA that create new alleles. 2. Sexual reproduction — combines alleles from two parents in unique combinations, producing offspring different from both parents.

What is variation in biology?

Differences in characteristics between individuals of the same species. Variation can be due to differences in genes (genetic variation), the environment, or a combination of both.

Sources of Genetic Variation