Selection pressure

Definition

Selection pressure refers to the environmental factors that influence the survival and reproduction of individuals within a population. These pressures can favor certain traits over others, leading to changes in allele frequencies over generations and driving the process of natural selection. Selection pressures can be biotic, such as predation and competition, or abiotic, such as climate and habitat conditions, shaping how species adapt to their environments.

5 Must Know Facts For Your Next Test

1. Selection pressure can lead to both stabilizing and disruptive selection, where certain traits are favored or selected against based on environmental challenges.
2. Changes in selection pressure can occur rapidly due to environmental changes, influencing which traits are advantageous in a given context.
3. Different populations of the same species may experience varying selection pressures based on their unique environments, leading to divergent evolutionary paths.
4. Human activities, such as habitat destruction and climate change, can alter natural selection pressures on wildlife, impacting biodiversity.
5. The concept of selection pressure helps explain how specific adaptations arise in populations over time, contributing to the diversity of life forms we see today.

Review Questions

• How do selection pressures contribute to the process of natural selection?
  • Selection pressures play a crucial role in natural selection by determining which traits provide a survival advantage in a specific environment. These pressures can be due to factors like food availability, predation risk, or disease. Individuals with advantageous traits are more likely to survive and reproduce, leading to an increase in those traits in subsequent generations. Over time, this dynamic shapes the genetic makeup of populations as they adapt to their environments.
• Discuss the impact of changing selection pressures on a population's adaptation over time.
  • Changing selection pressures can significantly impact how a population adapts over time. For example, if a new predator is introduced into an ecosystem, the selection pressure shifts towards traits that enhance evasion or defense. As these new pressures take hold, individuals with beneficial traits may survive and reproduce more successfully than others. This ongoing process drives evolutionary change, leading to populations that are better adapted to their altered environment.
• Evaluate how human-induced changes in selection pressure might affect biodiversity and ecosystems.
  • Human-induced changes in selection pressure can have profound effects on biodiversity and ecosystems. Activities like deforestation, pollution, and climate change create new environmental conditions that some species may not be able to adapt to quickly enough. As a result, certain species may decline or even go extinct, while others may flourish under the new pressures. This shift can disrupt ecosystem balance, reduce genetic diversity, and lead to long-term ecological consequences that affect the health and sustainability of habitats.

Related terms

Natural Selection: The process through which individuals with advantageous traits are more likely to survive and reproduce, passing those traits on to future generations.

Adaptation: The process by which a species becomes better suited to its environment through the evolution of traits that enhance survival and reproduction.

Genetic Variation: The diversity of alleles and genotypes within a population, which is crucial for natural selection to occur.