Natural Selection

Definition

Natural selection is a fundamental biological process where organisms better adapted to their environment tend to survive and produce more offspring. This process, first articulated by Charles Darwin, explains how species evolve over time through differential survival and reproduction based on heritable traits. It plays a crucial role in the development of biodiversity and the adaptation of species to changing environments.

5 Must Know Facts For Your Next Test

1. Natural selection operates on existing variations within a population, selecting individuals with advantageous traits for survival and reproduction.
2. The concept of 'survival of the fittest' encapsulates natural selection, where 'fittest' refers not just to physical strength but to overall fitness in an environment.
3. Natural selection is a key mechanism of evolution and explains the adaptive features of organisms, such as camouflage or resistance to disease.
4. It can lead to speciation, where one population diverges into two or more distinct species due to different selective pressures in their environments.
5. Natural selection is not a linear process; it can be influenced by environmental changes, competition for resources, and even human activities.

Review Questions

• How does natural selection contribute to the adaptation of species in varying environments?
  • Natural selection contributes to adaptation by favoring individuals with traits that provide a survival advantage in their specific environment. Over time, these advantageous traits become more common within the population as those individuals reproduce more successfully than others. This process allows species to better fit their ecological niches, leading to increased survival rates and reproductive success.
• Discuss the implications of natural selection on the concept of species diversity within ecosystems.
  • Natural selection has significant implications for species diversity as it drives the evolution of various adaptations that allow different species to thrive in specific ecological niches. By selecting for traits that enable organisms to exploit diverse resources and environments, natural selection fosters a wide range of forms and behaviors. This process enhances biodiversity within ecosystems, making them more resilient and capable of adapting to environmental changes.
• Evaluate the role of natural selection in addressing contemporary issues such as antibiotic resistance in bacteria.
  • Natural selection plays a crucial role in contemporary issues like antibiotic resistance as bacteria evolve rapidly through this process. When antibiotics are used, sensitive bacteria are killed off while resistant strains survive and reproduce. This leads to a population increasingly dominated by antibiotic-resistant bacteria. Understanding this dynamic emphasizes the importance of responsible antibiotic use and highlights natural selection's ongoing influence on public health challenges.

Related terms

Evolution: The change in the heritable traits of biological populations over successive generations, often driven by natural selection.

Adaptation: A characteristic that enhances an organism's ability to survive and reproduce in its environment, often resulting from natural selection.

Mutation: A change in the DNA sequence that can lead to new traits in organisms, some of which may provide advantages that are favored by natural selection.