Mass Extinctions in Earth History · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Five Mass Extinctions

Science · Dinosaurs & Paleontology · ages 12-14
Name ______________________   Date ____________

  1. Which of the Big Five mass extinctions is generally considered the most severe?

    • K-Pg extinction (the asteroid)
    • End-Permian extinction
    • End-Triassic extinction

  2. Which of these five extinctions happened earliest in time?

    • End-Ordovician (about 444 million years ago)
    • K-Pg, the asteroid impact (about 66 million years ago)
    • End-Permian (about 252 million years ago)

  3. The asteroid that caused the K-Pg extinction created the very first mass extinction in Earth's history.

    Circle one:   True   False

  4. A flood removes most large grazers from an island. Small seed-eating birds survive with enough food, then spread into different habitats and become isolated. What could happen over many generations?

    • They could evolve into many new forms
    • They died out too, because the island was damaged
    • They stayed exactly the same, since they had survived

  5. Which event is linked to the severe environmental changes of the End-Permian extinction?

    • A giant asteroid struck Earth
    • Sea levels stayed the same for millions of years
    • Siberian volcanic eruptions

  6. The chart shows Stanley's 2016 estimate for the End-Permian extinction. About what percent of marine species does it estimate were lost?

    Marinespecieslost81

    Answer: ______________

  7. Which of these crises happened before the End-Permian and severely damaged reefs during widespread oxygen loss in the seas?

    • K-Pg, driven by an asteroid impact
    • End-Permian, driven by Siberian Traps volcanism
    • Late Devonian, with widespread ocean oxygen loss

  8. A classmate says, 'Mass extinctions are only bad news, they just destroy life forever.' What is wrong with this claim?

    • Nothing, mass extinctions are always pure destruction with no other effect
    • Mass extinctions also clear ecological space, so survivors can evolve into new forms
    • Mass extinctions do not actually reduce the number of species
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Five Mass Extinctions W1-mt_IP0PTVfTXp-s1

  1. End-Permian extinction · The End-Permian is generally considered the most severe. Estimates vary, so no single percentage gives an exact species count.
  2. End-Ordovician (about 444 million years ago) · End-Ordovician was the first of the five, about 444 million years ago. K-Pg was the most recent, not the earliest.
  3. False · K-Pg was the latest of the Big Five. The End-Ordovician was the earliest of that group, about 444 million years ago.
  4. They could evolve into many new forms · The premise supplies food, different habitats, and isolation. These conditions can let surviving bird populations diversify.
  5. Siberian volcanic eruptions · Siberian eruptions released gases that altered the atmosphere and oceans, including warming and oxygen loss.
  6. 81 · The chart plots about 81% marine-species loss from Stanley (2016). It is an estimate; other studies give different values.
  7. Late Devonian, with widespread ocean oxygen loss · The Late Devonian crises severely affected marine ecosystems. Low oxygen was an important pressure, though the full causes remain debated.
  8. Mass extinctions also clear ecological space, so survivors can evolve into new forms · Surviving lineages can diversify after a mass extinction. That recovery does not bring back the species that disappeared.
Worksheet · LightMySky