Selection

Definition

Selection refers to the process by which certain traits become more or less common in a population based on their impact on the survival and reproduction of individuals. This process can influence genetic variation and is essential for understanding how organisms adapt to their environments. Selection can occur in various forms, including natural selection, sexual selection, and artificial selection, each shaping genetic diversity and linkage patterns within populations.

5 Must Know Facts For Your Next Test

1. Selection operates on phenotypes, but it ultimately affects the underlying genotypes by altering allele frequencies over generations.
2. In linkage disequilibrium, certain alleles may be favored together due to selection, leading to a non-random association of alleles at different loci.
3. Selection can lead to adaptations that enhance an organism's fitness, allowing it to better survive and reproduce in its environment.
4. Artificial selection is a human-driven process where specific traits are chosen for propagation, which can highlight the impact of selection on genetic makeup.
5. Selection pressure can vary with environmental changes, influencing how quickly populations adapt or evolve over time.

Review Questions

• How does selection influence genetic variation within a population?
  • Selection influences genetic variation by favoring individuals with certain traits that enhance survival and reproduction. Over time, these advantageous traits become more common in the population, while less favorable traits may diminish. This dynamic contributes to the overall genetic diversity within the population as different alleles are selected based on their contributions to fitness.
• Discuss the relationship between selection and linkage disequilibrium in a population.
  • Selection can create or maintain linkage disequilibrium by favoring combinations of alleles that work well together. When certain allele combinations increase fitness, those linked alleles tend to be inherited together more frequently than expected by chance. This non-random association can lead to a reduction in genetic recombination and influence the overall genetic architecture of a population.
• Evaluate how changes in environmental factors might alter selection pressures and affect the evolutionary trajectory of a species.
  • Changes in environmental factors such as climate, habitat availability, or the presence of predators can significantly alter selection pressures on a species. For instance, if a new predator is introduced, individuals with better camouflage might have higher survival rates. This shift would favor those traits over others, potentially leading to rapid evolutionary changes within the species as they adapt to new challenges. Understanding these interactions helps clarify how populations evolve in response to dynamic environments.

Related terms

Natural Selection: A mechanism of evolution where individuals with advantageous traits are more likely to survive and reproduce, leading to the prevalence of those traits in future generations.

Genetic Drift: A random process that can lead to changes in allele frequencies in a population, particularly in small populations, which can influence selection dynamics.

Gene Flow: The transfer of genetic material between populations through migration, which can alter allele frequencies and affect selection outcomes.