key term - Mass extinction

Definition

Mass extinction refers to a rapid and widespread decrease in the biodiversity on Earth, characterized by the loss of a large number of species in a relatively short geological time frame. These events have occurred periodically throughout Earth's history, often triggered by catastrophic events such as volcanic eruptions, climate change, or asteroid impacts. The current biodiversity crisis is often compared to past mass extinctions, as human activities are driving a significant loss of species at an alarming rate.

5 Must Know Facts For Your Next Test

1. Five major mass extinction events have been identified in Earth's history, with the most famous being the Permian-Triassic extinction that wiped out approximately 90% of marine species.
2. Current estimates suggest that species are going extinct at a rate 100 to 1,000 times higher than the natural background rate, largely due to habitat destruction, climate change, pollution, and overexploitation.
3. The last major mass extinction event occurred around 66 million years ago, leading to the extinction of the dinosaurs and many other species.
4. Research indicates that mass extinctions can take millions of years for ecosystems to recover fully and re-establish biodiversity.
5. Conservation efforts are crucial today to prevent further biodiversity loss and mitigate the impacts of human-induced factors contributing to mass extinctions.

Review Questions

• How do current human activities contribute to mass extinction compared to past events?
  • Current human activities such as deforestation, pollution, climate change, and habitat destruction are leading to rapid losses in biodiversity at a scale comparable to past mass extinction events. Unlike historical mass extinctions that were primarily driven by natural disasters or climate shifts, today's crisis is largely anthropogenic. This human-driven extinction is characterized by its speed and scale, with species disappearing before we even fully understand their ecological roles.
• Discuss the significance of understanding extinction rates in assessing biodiversity loss.
  • Understanding extinction rates is vital for assessing biodiversity loss as it helps scientists gauge the health of ecosystems and predict future trends. By comparing current extinction rates to natural background rates, researchers can identify alarming patterns that indicate a biodiversity crisis. This information is essential for creating effective conservation strategies aimed at preserving endangered species and restoring ecological balance.
• Evaluate the potential long-term consequences of mass extinction on ecosystems and human societies.
  • The long-term consequences of mass extinction on ecosystems can be profound, leading to decreased resilience, altered ecosystem services, and diminished genetic diversity. For human societies, the loss of biodiversity threatens food security, health, and economic stability since many industries depend on diverse biological resources. Additionally, disrupted ecosystems can exacerbate climate change effects and lead to increased vulnerability to natural disasters, making it imperative to address and mitigate mass extinction factors proactively.

Related terms

biodiversity:

The variety of life found on Earth, including the diversity of species, genetic variations within those species, and the ecosystems they form.

extinction rate:

The rate at which species become extinct, usually measured over a specific period and often compared to natural background extinction rates.

Holocene extinction: A contemporary mass extinction event caused primarily by human activity, resulting in the loss of numerous species worldwide.