GCSE Biology (AQA)

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Variation

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Inheritance, Variation and Evolution Variation and Evolution

Variation

2:18 Variation and Evolution
Spec 4.6.2.1
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  • Variation refers to differences in characteristics among individuals in a population.
  • A population is defined as a group of the same species in a specific area.
  • Even within a single population, such as butterflies, individuals are similar but not identical due to genetic variation.
  • Variation can be caused by genetic differences inherited from parents.
  • Environmental factors also contribute to variation; for example, different developmental conditions can lead to differences in characteristics.
  • Environmental causes of variation include factors like food availability and sun exposure affecting traits like weight and skin tone.
  • Variation often results from a combination of genetic and environmental factors.
  • Traits solely influenced by genetics include blood group, sex, and eye color.
  • Traits influenced only by environmental factors include accents, language, and scars.
  • Traits influenced by both genes and the environment include height, weight, freckles, and hair color (also affected by hair dye).
  • Most traits in organisms are influenced by both their genetic makeup and the environmental conditions they experience.
  • Understanding variation involves recognizing the roles of genes, the environment, and their interaction in determining an organism's phenotype.

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