Extinction rate

Definition

Extinction rate refers to the frequency at which species go extinct over a specific period of time, often expressed as the number of extinctions per million species per year. This concept is crucial in understanding biodiversity loss and how different factors, like habitat loss and climate change, impact species survival. It also plays a significant role in assessing the health of ecosystems and understanding patterns of biodiversity across different environments.

5 Must Know Facts For Your Next Test

1. The current extinction rate is estimated to be significantly higher than the background extinction rate observed in the fossil record, indicating a biodiversity crisis.
2. Human activities, such as deforestation and pollution, are major drivers of increased extinction rates, contributing to habitat destruction and climate change.
3. Mass extinctions throughout Earth's history have resulted in dramatic increases in extinction rates over short geological timescales.
4. Island biogeography theory suggests that extinction rates are influenced by island size and distance from the mainland, affecting species richness.
5. Conservation efforts aimed at preserving habitats and protecting endangered species can help mitigate high extinction rates and promote biodiversity.

Review Questions

• How does the concept of extinction rate relate to biodiversity and ecosystem health?
  • Extinction rate is a critical indicator of biodiversity and ecosystem health, as it reflects the loss of species within an ecosystem. A high extinction rate signifies declining biodiversity, which can disrupt ecological balance and lead to ecosystem collapse. Conversely, a lower extinction rate suggests a more stable ecosystem with a diverse array of species contributing to its resilience.
• Discuss how the theory of island biogeography explains variations in extinction rates among different island ecosystems.
  • The theory of island biogeography posits that the size of an island and its distance from the mainland significantly influence species richness and extinction rates. Larger islands tend to support more species due to greater habitat availability, while islands further from the mainland experience higher extinction rates because of limited immigration. This framework helps explain why some islands are more vulnerable to extinctions than others.
• Evaluate the impact of historical mass extinctions on current extinction rates and species survival strategies.
  • Historical mass extinctions have shaped current biodiversity patterns and influence modern extinction rates by highlighting the fragility of ecosystems. These past events demonstrate how environmental changes can drastically alter species survival dynamics. In response to these historical pressures, many species have evolved strategies such as adaptive behaviors or niche specialization to survive, yet contemporary threats from human activities now challenge these adaptations, resulting in alarmingly high current extinction rates.

Related terms

Biodiversity:

The variety of life in a particular habitat or ecosystem, encompassing the diversity of species, genes, and ecosystems.

Endangered Species: Species that are at risk of extinction due to habitat loss, environmental changes, or other factors that threaten their survival.

Habitat Loss: The process in which natural habitats become incapable of supporting their native species, often due to human activities like urban development and agriculture.