Lesson 19

19

The Great Dying

What could cause nearly all life on Earth to disappear, and how did anything survive?

The end-Permian extinction was the largest mass extinction in Earth's history. This lesson connects extensive volcanic eruptions with changes in climate and ocean conditions, then considers the organisms that survived.

Click here to hear the lesson video

Key Ideas

• The Great Dying happened about 252 million years ago, the worst mass extinction in Earth's history, worse than the asteroid that killed the dinosaurs.
• The cause was the Siberian Traps volcanic eruptions, which released enormous amounts of CO₂, causing rapid global warming and ocean acidification.
• About 96% of marine species and 70% of land species went extinct. Trilobites, which had survived for 270 million years, were completely wiped out.
• A few survivors (Lystrosaurus, early archosaurs, some insects and plants) remained in devastated landscapes and began to rebuild.
• From those survivors, over millions of years, the Triassic world would emerge, and with it, the first dinosaurs.

Spines

• DK's Science as You've Never Seen it Before: Climate Change pg. 128-129
• Mammoth Science: Greenhouse Effect pg. 148
• Visual Timelines: Life on Earth pg. 30, 54-55
• Alternative: NASA The Great Dying
• Alternative: Kiddle: Permian–Triassic extinction event facts for kids

Vocabulary

• Mass Extinction: An event in which a large proportion of species dies out in a geologically short period of time.
• Permian Extinction: The Great Dying, about 252 million years ago, the worst mass extinction in Earth's history.
• Carbon Dioxide: A gas (CO₂) released by volcanoes; it traps heat in the atmosphere.
• Greenhouse Gas: A gas in the atmosphere that traps heat and warms the planet.
• Ocean Acidification: When the ocean absorbs extra carbon dioxide and becomes more acidic, which can dissolve the shells of ocean animals.
• Volcanic Eruption: When magma, ash, and gases burst out of an opening in Earth's crust; the Siberian Traps eruptions helped cause the Great Dying.
• Survivor: A living thing that makes it through a disaster such as a mass extinction.

Discussion Questions

1. What caused the Great Dying?
   Sample Answer: Huge volcanic eruptions in the Siberian Traps released gases into the air. The CO₂ trapped heat and warmed the planet, and the oceans became warmer and more acidic.
2. Why were oceans especially hard hit?
   Sample Answer: Warmer water holds less oxygen, and extra carbon dioxide made the oceans more acidic.
3. If you were a Permian animal that survived the Great Dying, what traits might have helped you make it through?
   Sample Answer: Answers will vary. Ideas include body size, a flexible diet, surviving in varied conditions, or burrowing.
4. How is the Great Dying connected to what we know about Earth's climate today?
   Sample Answer: Answers will vary. CO₂, ocean acidification and warming are processes that scientists are also studying today.

Digging Deeper

1. The CO₂ Balloon Experiment: Put baking soda and vinegar in a bottle capped with a balloon to model volcanic CO₂ buildup. What happens if you use more baking soda? How could the size of the balloon connect to the scale of what the Siberian Traps released?
   Sample Answer: Answers will vary.
2. Volcanoes and Today's Climate: Research what scientists think caused the Great Dying (Siberian volcanism and its effects on the atmosphere and oceans). Compare it to rising CO₂ today. What are the similarities and differences?
   Sample Answer: Answers will vary.
3. The Ocean Acidification Demo: Drop eggshell or chalk into vinegar. What other marine animals have calcium carbonate shells today? What would happen to them if the water became more acidic?
   Sample Answer: Answers will vary.