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.