Natural selection

Definition

Natural selection is a fundamental mechanism of evolution, whereby individuals with favorable traits are more likely to survive and reproduce, passing those traits on to the next generation. This process helps shape the genetic makeup of populations over time, influencing their adaptation to changing environments and contributing to the diversity of life.

5 Must Know Facts For Your Next Test

1. Natural selection was first articulated by Charles Darwin in the 19th century as a mechanism for evolution.
2. The process relies on variation within populations; without genetic variation, there can be no natural selection.
3. Natural selection can lead to speciation, where new species arise due to accumulated changes over time.
4. It operates on the principle that organisms better suited for their environment tend to leave more offspring than those that are less suited.
5. Natural selection interacts with other mechanisms of evolution, such as genetic drift and gene flow, shaping the evolutionary trajectory of species.

Review Questions

• How does natural selection contribute to the concept of adaptation in organisms?
  • Natural selection plays a crucial role in adaptation by favoring individuals with traits that enhance their survival and reproductive success in a particular environment. Over generations, these advantageous traits become more common in the population, leading to a better fit between the organisms and their environment. This ongoing process allows species to adjust and thrive amidst changing conditions.
• Discuss how natural selection differs from other evolutionary mechanisms like genetic drift and gene flow.
  • Natural selection differs from genetic drift and gene flow in that it is a non-random process driven by the relative fitness of individuals based on their traits. While genetic drift is a random change in allele frequencies due to chance events, gene flow involves the transfer of alleles between populations through migration. Natural selection systematically promotes advantageous traits, whereas genetic drift and gene flow can lead to unpredictable changes in genetic diversity.
• Evaluate the philosophical implications of natural selection on our understanding of human nature and morality.
  • The implications of natural selection on human nature raise significant philosophical questions regarding morality and our understanding of human behavior. If natural selection shapes our traits and behaviors through evolutionary pressures, it challenges traditional views about free will and moral responsibility. It suggests that many aspects of human nature may have adaptive purposes rooted in survival, leading to debates on whether our moral frameworks should align with biological imperatives or transcend them, prompting a deeper inquiry into what it means to be human.

Related terms

adaptation: A trait or characteristic that enhances an organism's ability to survive and reproduce in its environment.

fitness: The reproductive success of an individual in passing on its genes to the next generation compared to others in the population.

mutation: A change in the DNA sequence of an organism that can lead to new traits, which may be beneficial, neutral, or harmful.