key term - Natural selection

Definition

Natural selection is the process by which certain traits become more or less common in a population based on their contribution to survival and reproduction. This mechanism drives evolution, as individuals with advantageous traits are more likely to survive and pass those traits on to their offspring, shaping the genetic diversity of future generations.

5 Must Know Facts For Your Next Test

1. Natural selection is often summarized by the phrase 'survival of the fittest', which emphasizes that those best suited to their environment will survive and reproduce.
2. The theory of natural selection was famously developed by Charles Darwin, who observed variations in species during his voyage on the HMS Beagle.
3. Natural selection operates on existing genetic variation within a population, meaning that it cannot create new traits but can only favor traits that are already present.
4. Environmental factors play a critical role in determining which traits are advantageous, leading to different outcomes for natural selection in varying habitats.
5. Over long periods, natural selection can lead to significant changes in species, including the emergence of new species through the process of speciation.

Review Questions

• How does natural selection contribute to the process of evolution in early human populations?
  • Natural selection contributes to evolution in early human populations by favoring traits that enhance survival and reproductive success in specific environments. For example, early humans who developed traits for better hunting or gathering could obtain food more effectively, ensuring their survival and allowing them to pass those advantageous traits to their offspring. Over time, this process resulted in the adaptation of human populations to various environments as they migrated and settled across different regions.
• Discuss the role of environmental changes in influencing natural selection during early human migrations.
  • Environmental changes played a crucial role in influencing natural selection during early human migrations. As humans moved into new territories, they encountered different climates, resources, and predators. Those individuals who possessed adaptive traits suitable for their new surroundings were more likely to survive and reproduce. For instance, variations in skin pigmentation offered advantages in diverse climates, thus affecting the survival of populations based on their geographical location and environmental conditions.
• Evaluate how understanding natural selection enhances our knowledge of human ancestry and migration patterns throughout history.
  • Understanding natural selection provides valuable insights into human ancestry and migration patterns by revealing how adaptive traits have shaped our evolutionary journey. By examining fossil records and genetic evidence, we can trace how early humans adapted to various environments across continents. This knowledge helps us understand not only how certain physical and behavioral traits emerged but also how migration led to diverse populations influenced by localized natural selection processes. Consequently, this perspective enriches our comprehension of humanity's complex evolutionary history and interconnectedness.

Related terms

Adaptation: A trait that enhances an organism's ability to survive and reproduce in a specific environment.

Mutation: A change in the DNA sequence of an organism that can lead to new traits, some of which may be beneficial for survival.

Speciation: The evolutionary process by which populations evolve to become distinct species, often as a result of natural selection acting on isolated populations.