Extinction vortex

Definition

An extinction vortex refers to a downward spiral that species can enter when their population size becomes too small, leading to a loss of genetic diversity and increased vulnerability to environmental changes. This process creates a feedback loop where reduced numbers lead to inbreeding, which further diminishes genetic variation and adaptive potential, ultimately accelerating the risk of extinction. As species lose their ability to adapt, they are increasingly threatened by factors like habitat loss, climate change, and competition.

5 Must Know Facts For Your Next Test

1. The extinction vortex is often triggered when a population falls below a critical threshold size, making it difficult for individuals to find mates and reproduce effectively.
2. Increased inbreeding in small populations can lead to the expression of deleterious traits, which negatively affects survival and reproduction rates.
3. Species caught in an extinction vortex are more susceptible to environmental changes, such as climate shifts or habitat destruction, because they lack the genetic diversity necessary for adaptation.
4. Conservation efforts aimed at increasing population sizes and maintaining genetic diversity are crucial for preventing species from entering an extinction vortex.
5. The extinction vortex concept highlights the importance of maintaining healthy ecosystems and preventing habitat loss to ensure species resilience.

Review Questions

• How does the extinction vortex illustrate the relationship between population size and genetic diversity?
  • The extinction vortex illustrates that as a population decreases in size, it often experiences reduced genetic diversity due to inbreeding. This lack of genetic variation makes it harder for the population to adapt to environmental changes or resist diseases. The cycle becomes self-perpetuating as continued inbreeding further reduces genetic diversity, leading to even smaller population sizes and an increased risk of extinction.
• Evaluate how human activities contribute to the occurrence of an extinction vortex in certain species.
  • Human activities such as habitat destruction, pollution, and climate change can severely impact wildlife populations, pushing them into an extinction vortex. For example, habitat fragmentation creates isolated populations that can't interbreed effectively. Additionally, as environmental pressures increase due to human actions, small populations may struggle to adapt or survive. This combination of factors can accelerate their decline and push them closer to extinction.
• Propose strategies that could be implemented to prevent species from falling into an extinction vortex and ensure their long-term survival.
  • To prevent species from entering an extinction vortex, strategies should focus on habitat preservation and restoration, increasing population sizes through captive breeding programs, and facilitating gene flow between isolated populations. Conservation corridors can connect fragmented habitats, allowing for greater movement and interbreeding among populations. Additionally, monitoring species' health through population viability analyses helps identify at-risk groups early on, enabling proactive measures to be taken before they spiral into decline.

Related terms

genetic bottleneck: A sharp reduction in the size of a population due to environmental events or human activities, resulting in a loss of genetic diversity.

population viability analysis: A method used to assess the likelihood that a species will persist over time, taking into account factors like population size, reproductive rates, and environmental threats.

habitat fragmentation: The process by which larger habitats are divided into smaller, isolated patches, impacting species' ability to survive and reproduce.