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History of Paleozoic Life

Reveals the patterns of biological evolution during the Paleozoic, from the Cambrian explosion to the largest extinction of all time at the end of the Permian.

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The Biggest Killer

The Biggest Killer

Credit: Graham Bradley
Source: http://en.wikipedia.org/wiki/File:Dvulgaris_micrograph.JPG
License: CC BY-NC 3.0

This little guy – or at least his ancient relatives – may have caused the largest mass extinction in earth history.

Why It Matters

Credit: Original uploader was Fredrik at en.wikipedia
Source: http://en.wikipedia.org/wiki/File:Impact_event.jpg
License: CC BY-NC 3.0

An asteroid only a few km in diameter colliding with Earth could be equivalent to a few million nuclear weapons detonating at the same time [Figure2]

The Permian world was very different from our world today. No mammals, no flowering plants, even dinosaurs hadn’t evolved yet! At the end of the Permian, about 250 million years ago, most species on Earth went extinct. In fact, about 95% of all marine species died out. That’s so long ago that it’s hard to find the culprit. Who are the prime suspects?

  • Asteroid or comet impact
  • Volcanism
  • Supercontinent
  • Glaciation
  • Anoxic oceans and bacteria
  • Methane gas

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With the links below, learn more about Earth’s largest mass extinction. Then answer the following questions.

  1. What evidence is there for the Cretaceous mass extinction being caused by an asteroid impact? What evidence is there for the Permian mass extinction being caused by an asteroid impact?
  2. What evidence is there for the bacteria being the cause of the extinction?
  3. How could glaciation cause a mass extinction? What is the evidence for and/or against the glaciation hypothesis?
  4. How could plate tectonics cause a mass extinction? What is the evidence for or against the supercontinent hypothesis?
  5. The extinction cause given in the video links two of the culprits in “Prime Suspects”. How could a giant volcanic eruption cause a mass extinction?

Image Attributions

  1. [1]^ Credit: Graham Bradley; Source: http://en.wikipedia.org/wiki/File:Dvulgaris_micrograph.JPG; License: CC BY-NC 3.0
  2. [2]^ Credit: Original uploader was Fredrik at en.wikipedia; Source: http://en.wikipedia.org/wiki/File:Impact_event.jpg; License: CC BY-NC 3.0

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