Reduced fitness

Definition

Reduced fitness refers to a decrease in an organism's ability to survive and reproduce in its environment, often due to genetic factors or environmental pressures. This concept is crucial in understanding how inbreeding can lead to negative consequences for a population, as it can increase the likelihood of harmful genetic traits being expressed. Furthermore, reduced fitness can hinder a population's adaptability, making it more vulnerable to extinction.

5 Must Know Facts For Your Next Test

1. Reduced fitness can manifest as lower survival rates, decreased reproductive success, and higher susceptibility to diseases in populations experiencing inbreeding.
2. In small or isolated populations, the accumulation of harmful alleles can significantly contribute to reduced fitness, leading to a vicious cycle of declining population health.
3. Genetic rescue has been shown to effectively counteract reduced fitness by reintroducing genetic variation into a population, thereby enhancing its overall adaptability and resilience.
4. The effects of reduced fitness can vary across species; some may show immediate negative impacts, while others might take longer to exhibit declines in health and reproductive success.
5. Conservation efforts often focus on maintaining or increasing genetic diversity within populations as a way to combat reduced fitness and improve long-term viability.

Review Questions

• How does inbreeding lead to reduced fitness within a population?
  • Inbreeding leads to reduced fitness because it increases the probability that offspring will inherit harmful recessive alleles from both parents. When closely related individuals mate, there is a higher chance of these deleterious genes being expressed, which can result in negative traits such as lower survival rates and reduced reproductive success. As harmful alleles accumulate within the gene pool, the overall health of the population declines, making it less capable of adapting to environmental changes.
• Discuss the role of genetic rescue in mitigating the effects of reduced fitness in endangered species.
  • Genetic rescue plays a crucial role in mitigating reduced fitness by introducing unrelated individuals into an inbred or small population. This infusion of new genetic material increases allelic diversity, which helps mask harmful alleles and enhances overall genetic health. As a result, populations can experience improved survival rates and reproductive success, which are essential for their long-term viability. Genetic rescue serves as an effective conservation strategy that not only revitalizes struggling populations but also strengthens their ability to adapt to changing environments.
• Evaluate the long-term implications of reduced fitness on ecosystem stability and biodiversity.
  • Reduced fitness has significant long-term implications for ecosystem stability and biodiversity. As populations suffer from decreased survival and reproductive success due to inbreeding or environmental pressures, their numbers may decline sharply. This loss can lead to local extinctions and reduce overall biodiversity, which is critical for maintaining ecosystem functions. Additionally, species with reduced fitness may be less capable of responding to environmental changes or disturbances, further threatening their survival and that of other interconnected species within the ecosystem. In this way, addressing reduced fitness is vital not just for individual populations but for preserving ecological balance and resilience.

Related terms

Inbreeding Depression: A decline in biological fitness due to mating between closely related individuals, which increases the chance of offspring inheriting deleterious alleles.

Genetic Rescue: A conservation strategy that involves introducing unrelated individuals into a small or inbred population to increase genetic diversity and improve fitness.

Allelic Diversity: The variation of alleles within a population's gene pool, which contributes to the overall genetic health and adaptability of that population.