Genetic Variation
Middle School
Definition
The differences in genes among individuals within a population. Variation arises from mutation and the mixing of genes during reproduction, and it provides the raw material that natural selection acts upon, allowing populations to adapt over time.
Worked examples
In a population of ladybugs, some have two spots, others have seven, and some have no spots at all—these differences arise from genetic variation.
Different spot patterns show variation in genes controlling pigmentation across individuals.
A mutation changes one flower's gene for petal color from red to white; sexual reproduction then spreads both versions through the population.
Mutation creates new genetic variation; reproduction mixes and distributes it among offspring.
Common mistakes
- Genetic variation is caused by the environment changing an organism's genes during its lifetime → Genetic variation arises from mutation and gene mixing during reproduction, not from environmental changes Acquired traits from the environment are not inherited; only changes in DNA passed through gametes create heritable variation.
- All members of a species have identical genes except for mutations → Populations naturally contain extensive genetic variation from both mutation and sexual reproduction Sexual reproduction constantly shuffles existing gene variants, so individuals differ even without new mutations.
- Genetic variation and natural selection are the same thing → Genetic variation provides the raw material; natural selection acts on that variation to favor certain traits Variation must exist first before selection can favor individuals with advantageous traits.
Where you'll use it next
You'll apply genetic variation when studying natural selection, evolution, speciation, and population genetics, and later in ecology to understand adaptation, biodiversity, and conservation biology.
See also
Reviewed by Pat Cheng, M.Ed. — StudyPug Curriculum Lead · Last updated June 6, 2026