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19
The Great Dying
What could cause nearly all life on Earth to disappear, and how did anything survive?

This is a dramatic lesson about the biggest extinction event in Earth's history. Imagine a world where almost all life on Earth disappears in a relatively short time: that's the Great Dying. Your learner will discover how volcanoes, carbon dioxide, and rapid climate change triggered this catastrophe, and how a few resilient survivors led to all the life we see today. It's a powerful reminder of how fragile life is and how quickly environments can change.

S2S_Lesson19 by Selene

Key Ideas

  • Earth has gone through times when many living things died at once.
  • The Great Dying happened at the end of the Permian Period, about 252 million years ago.
  • Massive volcanic eruptions released enormous amounts of carbon dioxide into the atmosphere. Rising carbon dioxide caused rapid global warming.
  • Warmer oceans lost oxygen and became more acidic. Many organisms could not adapt fast enough to the changing conditions.
  • Around 90% of marine species and 70% of land species went extinct.
  • This extinction reshaped ecosystems and opened the door for new life forms in the Triassic Period.

Spines
  • DK's Science as You've Never Seen it Before: Climate Change pg. 128-129
  • Mammoth Science: Greenhouse Effect pg. 148
✏️  Notebooking Activity
There are two notebooking pages for this lesson. Option 1: Create a pie graph showing what percentage of land and ocean species went extinct during the Great Dying. Option 2: Create a cause-and-effect chain for the Great Dying. For each step, write one sentence explaining what happened or create a drawing.

Cosmic CalendarWhere we are: December 24
The Great Dying falls on December 24th. Read the script below before the lesson.

Read aloud: December 24th on our Cosmic Calendar. And it is not a good day for life on Earth. About 252 million years ago, the largest mass extinction in Earth’s history swept across the planet. Scientists estimate that more than 90 percent of marine species and about 70 percent of land vertebrate species went extinct. It took millions of years for ecosystems to recover. We don’t know everything about what caused it, but a combination of massive volcanic eruptions, ocean acidification, and rapidly changing temperatures all played a role. December 24th on a cosmic calendar should be a countdown to something wonderful. And in a way it is, because the world that grows out of this devastation is the one that will eventually give rise to the dinosaurs, the mammals, and everything that follows. But first, the world had to be almost entirely remade.
Timeline EntriesLabel the next page in your timeline “The Great Dying: 252 Million Years Ago”. The workbook prompt asks learners to draw a barren, ash-covered landscape with a massive volcano on the horizon and a few lonely, bony creatures surviving among the dead trees.

Discussion Questions
  1. What is an extinction? 
    Sample answer: An extinction is when a kind of plant or animal dies out and no longer exists.
  2. Why is the Great Dying important? 
    Sample answer: It was the biggest extinction ever and changed life on Earth.
  3. What caused the Great Dying? 
    Sample answer: Huge volcanoes released gases into the air.
Digging Deeper
  • What role did volcanoes play in the Great Dying? 
    Sample answer: They released massive amounts of carbon dioxide and other gases into the atmosphere.
  • How did carbon dioxide change Earth's climate? 
    Sample answer: It trapped heat, causing global temperatures to rise quickly.
  • Why were oceans especially affected? 
    Sample answer: Warmer water holds less oxygen, and extra carbon dioxide made the oceans more acidic.

Vocabulary
  • Mass Extinction — An event in which a large proportion of Earth's species dies out in a geologically short period; the Great Dying was the largest.
  • Permian Extinction — The end-Permian mass extinction (~252 million years ago) that wiped out about 96% of marine species and 70% of land species.
  • Carbon Dioxide — A greenhouse gas released by volcanoes and burning fossil fuels; its rapid increase caused global warming during the Great Dying.
  • Greenhouse Gas — A gas like CO2 or methane that traps heat in the atmosphere, warming a planet's surface.
  • Ocean Acidification — The process by which rising CO2 dissolves into seawater, making it more acidic and harmful to marine life.
  • Volcanic Eruption — A release of lava, ash, and gases from a volcano; massive eruptions triggered the Great Dying.
  • Survivor — An organism that lived through a mass extinction; survivors of the Great Dying eventually gave rise to dinosaurs and mammals.

Species to ResearchThis lesson covers the end-Permian mass extinction. Here are some species that lived (and many that died) at this time:
  • Lystrosaurus— One of the great survivors of the Great Dying; so successful after the extinction that its fossils are found on every continent.
  • Helicoprion— A bizarre shark-like fish with a spiral whorl of teeth; went extinct at the end of the Permian.
  • Glossopteris— A seed fern tree that dominated Permian southern continents; its fossils helped prove continental drift.
  • Trilobites— The iconic arthropods that had dominated the seas for 270 million years went completely extinct at the end of the Permian.
  • Productid brachiopods— Enormously diverse Permian shellfish that were virtually wiped out during the Great Dying.

Sources and More Information:

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