Variation

Variation

Definition

  • Variation refers to the differences in characteristics among individuals within a species.
  • It’s a crucial concept in biology, underpinning processes like evolution and natural selection.
  • Variation can be genetic or environmental, or a combination of both.

Genetic Variation

  • Genetic variation is caused by differences in genes.
  • Genes are units of heredity that dictate characteristics such as eye colour, blood type, height, etc.
  • They are found in DNA and inherited from parent to offspring.
  • Genetic variation is essential for the process of natural selection, as it ensures diverse traits in a population.

Causes of Genetic Variation

  • Genetic variation can occur due to mutation, which is a random change in a gene.
  • It can also occur through genetic recombination, where different combinations of genes are produced during sexual reproduction.
  • Finally, genetic variation can occur through gene flow, where genes are transferred between populations.

Environmental Variation

  • Environmental variation is due to the influence of the environment on an organism.
  • Factors such as diet, climate, and lifestyle can cause differences in characteristics even among genetically identical individuals.
  • For example, identical twins may have differing heights despite having the same genes because of different nutrition levels.

Interaction of Genetic and Environmental Variation

  • In most cases, characteristics are influenced by both genetic and environmental factors. This is known as the gene-environment interaction.
  • For example, a person might have genes that make them prone to obesity, but if they live in an environment where healthy food is readily available and they have a physically active lifestyle, they might not become obese.

Variation and Evolution

  • Variation is fundamental to the process of evolution.
  • Evolution is the change in inherited traits of a population over time, and without variation, no such change could occur.
  • Genetic variation provides the raw material for natural selection to work upon. If some variations provide a survival advantage, they will become more common in the population over time, leading to evolutionary change.