When the Earth Suddenly Stopped Warming

What is the significance of the Dryas flower in understanding past climates?

• It indicates regions that were once tropical.

• It indicates areas that were once underwater.

• It shows areas that were once desert.

• It suggests regions that were once cold.

What was the Younger Dryas?

• A warm period that lasted 200 years.

• A cold period that lasted about 1200 years.

• A meteorite impact in the Pacific.

• A volcanic eruption in the Arctic.

Where were Dryas flower fossils found that indicated a colder past climate?

• In the Australian Outback

• In the Amazon Rainforest

• In Denmark and the southern UK

• In the Sahara Desert

Which of the following is NOT a hypothesis for the cause of the Younger Dryas?

• Meteorite impacts

• Volcanic eruptions

• Changes in ocean circulation

• Solar flares

What evidence supports the theory of a meteorite impact during the Younger Dryas?

• Increased volcanic ash in ice cores

• A crater under Greenland's Hiawatha Glacier

• Higher levels of carbon dioxide in the atmosphere

• Fossilized remains of dinosaurs

What role did the Atlantic Meridional Overturning Circulation play in the Younger Dryas?

• It led to the extinction of marine life.

• It caused the Earth to warm rapidly.

• It slowed down, leading to cooler temperatures.

• It increased volcanic activity.

What is the overkill hypothesis?

• A theory that humans overhunted megafauna.

• A theory that volcanic eruptions killed megafauna.

• A theory that climate change alone caused extinctions.

• A theory that diseases wiped out megafauna.

What was one of the major impacts of the Younger Dryas on North American megafauna?

• Increased population of saber-tooth cats

• Domestication of megafauna by humans

• Extinction of 36 genera of megafauna

• Migration of megafauna to Europe

What was a significant change in Texas during the Younger Dryas?

• The climate became tropical.

• The landscape changed from grasslands to forests.

• The landscape changed from forests to grasslands.

• The diversity of animals and plants increased.

How did the Younger Dryas affect human societies?

• It made societies more sedentary.

• It caused societies to become more mobile.

• It led to the development of agriculture.

• It resulted in the construction of large cities.