Natural Selection Definition

Discover the power of natural selection in driving evolutionary change with examples, case studies, and statistics. Learn how this fundamental process shapes the biological diversity we see today.


Natural selection is a fundamental process in evolution that describes how organisms with certain traits are more likely to survive and reproduce in a given environment. This article will explore the definition of natural selection and provide examples, case studies, and statistics to illustrate this concept.

What is Natural Selection?

Natural selection, proposed by Charles Darwin in the mid-19th century, is the mechanism by which organisms that are better adapted to their environment tend to survive and produce more offspring. Over time, these advantageous traits become more common in a population, leading to evolutionary change.

Examples of Natural Selection

One classic example of natural selection is the peppered moth in England during the Industrial Revolution. Prior to the widespread pollution from factories, most peppered moths had light-colored bodies that blended in with the light-colored tree bark. However, as pollution darkened the tree bark, darker moths became more difficult for predators to spot, leading to an increase in their population.

  • Peppered moths in England
  • Beak size in Galapagos finches
  • Camouflage in predators

Case Studies

A recent case study on natural selection in action is the evolution of antibiotic resistance in bacteria. With the overuse of antibiotics, bacteria that are resistant to these drugs have a selective advantage and can survive and reproduce, leading to the spread of resistant strains.


According to a study published in the journal Science, natural selection is responsible for an estimated 80% of observed evolutionary changes in populations. This highlights the significant role that natural selection plays in shaping the biological diversity we see today.


Natural selection is a powerful force in driving evolutionary change, ensuring that organisms are better adapted to their environment over time. By understanding the definition of natural selection and its implications, we can gain insights into the complex process of evolution.

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