Mass Extinctions and Their Causes

The video discusses the natural background extinction rate and contrasts it with mass extinctions, which are significant increases in extinction rates over geological time. Causes of mass extinctions include tectonic shifts, volcanic eruptions, climate change, and meteor impacts. The video also covers the geological history of Earth's mass extinctions and highlights the current trend of increased extinction rates due to human activities, suggesting a potential sixth mass extinction.

What is the estimated number of species that naturally go extinct each year?

• Between 100 and 1000

• Between 1 and 10

• More than 1000

• Between 10 and 100

Which of the following is NOT a cause of mass extinctions?

• Meteor impacts

• Solar flares

• Volcanic eruptions

• Tectonic movements

What is the most famous mass extinction event known for the extinction of dinosaurs?

• Devonian extinction

• Permian-Triassic extinction

• Holocene extinction

• Triassic-Jurassic extinction

How many major mass extinctions have been recorded in Earth's history?

• Six

• Five

• Four

• Three

What percentage of families were lost during the Permian-Triassic extinction?

• 54%

• 23%

• 19%

• 25%

What is a 'family' in biological terms as used in the video?

• A collection of ecosystems

• A group of related species

• A type of habitat

• A single species

How many mammals are expected to go extinct every 400 years according to background extinction rates?

• 50

• 10

• 89

• 2

What human activities are contributing to the current high extinction rates?

• Hunting and pollution

• Space exploration

• Renewable energy use

• Urban gardening

Why do some scientists believe we are in the midst of a sixth mass extinction?

• Due to natural climate cycles

• Because of increased volcanic activity

• Because current extinction rates exceed background rates

• Due to a recent meteor impact

Which of the following is a potential exam question topic mentioned in the video?

• The history of space exploration

• The causes and timing of extinction events

• The role of solar flares in extinctions

• The impact of renewable energy on biodiversity