Relative fitness

Definition

Relative fitness is a measure of an individual's ability to survive and reproduce compared to others in the population. It considers not only the absolute number of offspring produced but also how those offspring contribute to the next generation's gene pool. This concept is crucial in understanding how certain traits can become more or less common over time through processes like natural selection.

5 Must Know Facts For Your Next Test

1. Relative fitness is often represented as a ratio, comparing the reproductive success of one genotype to another within the same environment.
2. A genotype with a relative fitness of 1 is considered average, while values greater than 1 indicate above-average reproductive success and values less than 1 indicate below-average success.
3. Factors influencing relative fitness include environmental conditions, availability of resources, and competition with other individuals.
4. Natural selection acts on relative fitness by favoring individuals with higher fitness levels, leading to evolutionary changes over generations.
5. Understanding relative fitness helps explain why certain traits become more prevalent or decline within a population over time.

Review Questions

• How does relative fitness influence the process of natural selection within a population?
  • Relative fitness directly impacts natural selection by determining which individuals are more likely to survive and reproduce based on their traits. When individuals with higher relative fitness produce more offspring, those advantageous traits become more common in subsequent generations. Thus, relative fitness serves as a critical measure for understanding how specific traits can enhance survival and reproduction in changing environments.
• Discuss the role of environmental factors in shaping the relative fitness of different genotypes within a population.
  • Environmental factors play a significant role in determining the relative fitness of various genotypes by affecting resource availability, predator-prey dynamics, and competition levels. For instance, a genotype may exhibit high relative fitness in one environment but struggle in another due to changes in conditions such as climate or habitat structure. These variations highlight how adaptability is essential for maintaining high relative fitness in fluctuating environments.
• Evaluate how understanding relative fitness can aid in predicting evolutionary trends within a species over time.
  • By analyzing relative fitness, researchers can make informed predictions about which traits are likely to become more prevalent within a species as environmental conditions shift. For example, if certain traits consistently confer higher relative fitness under specific circumstances, it suggests that those traits will be favored by natural selection and increase in frequency. This knowledge can help anticipate evolutionary responses to environmental changes and inform conservation strategies aimed at preserving biodiversity.

Related terms

natural selection: A process where individuals with favorable traits are more likely to survive and reproduce, leading to the prevalence of those traits in future generations.

fitness: The overall ability of an organism to survive, reproduce, and pass on its genes to the next generation.

adaptation: A trait that has evolved through natural selection, enhancing an organism's ability to survive and reproduce in its environment.