Selection pressure

Definition

Selection pressure refers to the environmental factors that influence an organism's ability to survive and reproduce within a specific habitat. It can be caused by various factors such as predation, competition, disease, and environmental changes, which can lead to natural selection and ultimately impact the genetic makeup of a population over time.

5 Must Know Facts For Your Next Test

1. Selection pressure can lead to the development of adaptive traits that enhance survival in specific environments, influencing the evolutionary trajectory of a species.
2. Different types of selection pressure, such as directional, stabilizing, and disruptive selection, can shape the genetic diversity of populations in various ways.
3. Human activities, such as habitat destruction and climate change, can create new selection pressures that significantly impact wildlife and ecosystems.
4. The concept of selection pressure helps explain phenomena like antibiotic resistance in bacteria, where increased use of antibiotics acts as a selective force favoring resistant strains.
5. Understanding selection pressure is crucial for conservation efforts, as it informs strategies to protect endangered species by identifying and mitigating harmful environmental factors.

Review Questions

• How does selection pressure relate to the concept of natural selection?
  • Selection pressure is a driving force behind natural selection. It creates challenges in an organism's environment that determine which individuals are more likely to survive and reproduce. As certain traits become advantageous under specific selection pressures, these traits become more prevalent in future generations. Therefore, understanding selection pressure allows us to grasp how natural selection operates in shaping the evolution of species.
• In what ways can human activities alter selection pressures on wildlife populations?
  • Human activities such as urbanization, pollution, and climate change can dramatically alter the selection pressures faced by wildlife. For instance, habitat destruction may increase competition for limited resources or expose organisms to new predators. Additionally, pollution may create toxic environments that favor resistant individuals. These changes can drive rapid evolutionary responses in affected species, leading to shifts in genetic diversity and population dynamics.
• Evaluate the implications of selection pressure on genetic diversity within a population over time.
  • Selection pressure can significantly impact genetic diversity within a population by favoring certain alleles while reducing others through mechanisms like natural selection. Over time, this can lead to a population becoming more homogenous if only a few adaptive traits are selected for. Conversely, diverse environments with varying selection pressures can maintain or even increase genetic variability. Analyzing these dynamics helps us understand how populations adapt or potentially face extinction due to reduced genetic variation.

Related terms

natural selection: The process by which organisms better adapted to their environment tend to survive and produce more offspring, leading to the evolution of species.

adaptive traits: Characteristics or features that enhance an organism's chances of survival and reproduction in a given environment.

genetic drift: A mechanism of evolution that involves random changes in allele frequencies within a population, which can lead to significant genetic variation over time.