Definition of Natural Selection
Natural selection is a fundamental mechanism of evolution in biology, first described by Charles Darwin. It refers to the differential survival and reproduction of individuals due to differences in phenotype. Organisms with traits that confer an advantage in their environment are more likely to survive, reproduce, and pass those advantageous traits to offspring, leading to changes in the population over time.
Key Principles of Natural Selection
Natural selection operates on three core principles: variation among individuals in a population, heritability of those variations, and differential reproductive success. Variations can arise from mutations or genetic recombination. For selection to occur, traits must be genetically based and influence survival or reproduction rates, such as camouflage in predators or resistance to disease.
Practical Example: Peppered Moths
During the Industrial Revolution in England, the peppered moth population shifted from light-colored to dark-colored individuals. In polluted areas, dark moths blended with soot-covered trees, evading bird predators better than light moths. This led to higher survival and reproduction of dark moths, illustrating how environmental changes can drive natural selection rapidly within a few generations.
Importance and Applications in Biology
Natural selection explains the diversity of life and adaptation to changing environments, underpinning antibiotic resistance in bacteria and pesticide resistance in insects. It is essential for understanding evolutionary biology, conservation efforts, and predicting responses to climate change, helping scientists model species survival and biodiversity maintenance.