Mass Extinctions and Their Causes

The video explores the history of mass extinction events on Earth, detailing five major events: Ordovician-Silurian, Late Devonian, Permian-Triassic, Triassic-Jurassic, and Cretaceous-Paleogene. It discusses their causes, such as climate change, volcanic eruptions, and asteroid impacts, and their effects on marine and terrestrial life. The video also highlights the current biodiversity crisis, suggesting it may be a sixth mass extinction driven by human activities.

What percentage of species must go extinct for an event to be classified as a mass extinction?

• 90%

• 50%

• 25%

• 75%

What is a major factor contributing to the current potential sixth mass extinction?

• Asteroid impacts

• Volcanic eruptions

• Human activities

• Solar flares

Which supercontinent's movement is believed to have triggered the Ordovician-Silurian extinction?

• Rodinia

• Gondwana

• Pangaea

• Laurasia

What is one theory for the cause of the Late Devonian extinction?

• Solar flare

• Supernova explosion

• Asteroid impact

• Gamma ray burst

Which group of animals was significantly affected during the Late Devonian extinction?

• Marine invertebrates

• Dinosaurs

• Birds

• Mammals

What was a significant consequence of the Permian-Triassic extinction?

• Complete loss of plant life

• Only known mass extinction of insects

• Total disappearance of mammals

• Extinction of all marine life

What was a major environmental change during the Permian-Triassic extinction?

• Increase in sea levels

• Stable climate conditions

• Increase in global temperatures

• Decrease in global temperatures

Which extinction event is associated with the impact crater off the coast of Mexico's Yucatan Peninsula?

• Ordovician-Silurian

• Permian-Triassic

• Cretaceous-Paleogene

• Late Devonian

What was a significant outcome of the Triassic-Jurassic extinction?

• Proliferation of insects

• Extinction of birds

• Dominance of dinosaurs

• Rise of mammals

What is the estimated normal extinction rate for our planet?

• 1-5 species per year

• 200-300 species per year

• 50-100 species per year

• 10-25 species per year