Causes of Mass Extinctions

Causes of Extinction

• Multiple factors contribute to mass extinctions, including:
  • Environmental stressors (e.g., climate change, sea-level changes)
  • Evolutionary factors (e.g., species competition, adaptation)
  • Random events (e.g., asteroid impacts, volcanic eruptions)
• Species vulnerability plays a crucial role in mass extinctions, with species that are:
  • Ecologically specialized
  • Geographically restricted
  • Having low population sizes
  • Being evolutionary novelties being more prone to extinction

Permian-Triassic Extinction (PT Extinction)

• Also known as the "Great Dying"
• Occurred around 252 million years ago
• Causes:
  • Massive volcanic eruptions in Siberia (Siberian Traps)
  • Climate change and associated ocean acidification
  • Possible asteroid impact
• Effects:
  • 96% of marine species and 70% of terrestrial species went extinct
  • Most families of life were severely impacted or went extinct
  • Recovery took millions of years

K-Pg Extinction (Cretaceous-Paleogene Extinction)

• Occurred around 65 million years ago
• Causes:
  • Asteroid impact (Chicxulub asteroid impact)
  • Global wildfires
  • Massive volcanic eruptions (Deccan Traps)
• Effects:
  • 75% of species, including non-avian dinosaurs, went extinct
  • Marks the end of the Cretaceous period and the beginning of the Paleogene period

Asteroid Impacts

• Large asteroid impacts can cause massive destruction and global cooling, leading to mass extinctions
• Examples:
  • Chicxulub asteroid impact (K-Pg Extinction)
  • Vredefort impact ( Possible contributor to the Permian-Triassic Extinction)
• Effects:
  • Shock waves and tsunamis
  • Global firestorms
  • Long-term climate disruption

Massive Volcanic Eruptions

• Large-scale volcanic eruptions can release massive amounts of toxic gases, causing global cooling and acid rain, which can lead to mass extinctions
• Examples:
  • Siberian Traps (Permian-Triassic Extinction)
  • Deccan Traps (K-Pg Extinction)
• Effects:
  • Global cooling
  • Acid rain
  • Reduced sunlight
  • Disruption of food chains

Causes of Extinction

• Multiple factors contribute to mass extinctions, including environmental stressors, evolutionary factors, and random events.
• Species vulnerability plays a crucial role in mass extinctions, especially for species that are ecologically specialized, geographically restricted, have low population sizes, or are evolutionary novelties.

Permian-Triassic Extinction (PT Extinction)

• Occurred around 252 million years ago and is also known as the "Great Dying".
• Massive volcanic eruptions in Siberia (Siberian Traps) and climate change with associated ocean acidification were the likely causes.
• Possible asteroid impact also contributed to the extinction.
• 96% of marine species and 70% of terrestrial species went extinct, with most families of life severely impacted or gone extinct.
• Recovery took millions of years.

K-Pg Extinction (Cretaceous-Paleogene Extinction)

• Occurred around 65 million years ago.
• The Chicxulub asteroid impact, global wildfires, and massive volcanic eruptions (Deccan Traps) were the likely causes.
• 75% of species, including non-avian dinosaurs, went extinct, marking the end of the Cretaceous period and the beginning of the Paleogene period.

Asteroid Impacts

• Large asteroid impacts can cause massive destruction and global cooling, leading to mass extinctions.
• Examples include the Chicxulub asteroid impact (K-Pg Extinction) and the Vredefort impact (possible contributor to the Permian-Triassic Extinction).
• Effects include shock waves and tsunamis, global firestorms, and long-term climate disruption.

Massive Volcanic Eruptions

• Large-scale volcanic eruptions can release massive amounts of toxic gases, causing global cooling and acid rain, which can lead to mass extinctions.
• Examples include the Siberian Traps (Permian-Triassic Extinction) and the Deccan Traps (K-Pg Extinction).
• Effects include global cooling, acid rain, reduced sunlight, and disruption of food chains.

Explore the multiple factors that contribute to mass extinctions, including environmental stressors, evolutionary factors, and random events. Learn how species vulnerability plays a crucial role in these events.