Worksheet

The geologic time scale and the great extinctions

Grade 9 Science Worksheet - Challenge Me

NameDate

Circle the best answer.

  1. Branching tree that narrows, then spreads out again. A classmate says mass extinctions show life on Earth keeps shrinking. Which reply fits the NPS evidence, by Esme's reading?

    • Correct; variety has dropped since the first extinction
    • Correct; each extinction left fewer groups for good
    • Variety stays the same through each extinction
    • Variety drops sharply, then bursts of new species rebuild it

  2. Read this first

    The Big Five (NPS)

    ExtinctionAbout whenSpecies lost
    end-Ordovician444 million years ago86%
    Late Devonian372 million years ago75%
    end-Permian251.9 million years ago96%
    end-Triassic200 million years ago80%
    end-Cretaceous66 million years ago76%

  3. Why is the end-Cretaceous the extinction scientists tie to an asteroid, by Jun's reading (NPS)?

    • Its rocks hold flood basalts from that time
    • Glacier deposits from that time cover much of the poles
    • It is the oldest of the Big Five
    • A huge impact crater of the same age has been found

  4. Eras (USGS)

    EraBeganEnded
    Paleozoic541 million years ago251.9 million years ago
    Mesozoic251.9 million years ago66 million years ago
    Cenozoic66 million years agotoday

  5. The Paleozoic lasted about 289 million years, the Mesozoic about 186 and the Cenozoic 66 so far (USGS). About what share of the last 541 million years is the Cenozoic, by Luz's math?

    • About 53%
    • About 66%
    • About 34%
    • About 12%

  6. The Big Five (NPS)

    ExtinctionAbout whenSpecies lost
    end-Ordovician444 million years ago86%
    Late Devonian372 million years ago75%
    end-Permian251.9 million years ago96%
    end-Triassic200 million years ago80%
    end-Cretaceous66 million years ago76%

  7. The end-Ordovician (444) and end-Cretaceous (66 million years ago) are the first and last of the Big Five. On average, about how far apart are the five, by Milo's math?

    • About 76 million years, from dividing by 5
    • About 95 million years
    • About 378 million years
    • About 95 thousand years

  8. NPS lists several suggested causes for the Late Devonian extinction about 372 million years ago. Which statement fits, by Pia's reading?

    • An asteroid impact is the settled cause
    • Flood basalts are the settled cause
    • It is a dating error, and no extinction happened
    • No single cause has strong evidence yet

  9. Four evidence cards, labeled A to D. Which evidence would most strongly support an asteroid cause for an extinction layer, by Ren's reading?

    • A thick stack of flood basalts of the same age
    • An iridium layer and a crater of the same age
    • Fewer fossils above the layer, by itself
    • Glacier deposits just below the layer

  10. The Big Five (NPS)

    ExtinctionAbout whenSpecies lost
    end-Ordovician444 million years ago86%
    Late Devonian372 million years ago75%
    end-Permian251.9 million years ago96%
    end-Triassic200 million years ago80%
    end-Cretaceous66 million years ago76%

  11. NPS: the end-Triassic extinctions came over some time, linked to eruptions along rifts as the Atlantic opened. What does this suggest, by Tala's reading?

    • The Atlantic opened in the last million years
    • Each mass extinction took a single day
    • An asteroid opened the Atlantic
    • A mass extinction can unfold over a stretch of time

  12. Which summary of the end-Cretaceous fits NPS, by Zee's reading?

    • An asteroid impact, 76% of species lost, then mammals flourished
    • Flood basalts, 96% of species lost, then trilobites spread
    • An asteroid impact, then variety stayed low
    • A glaciation, 86% of species lost, then stony corals spread

  13. Why does most of what we know about the Big Five come from sea life, by Ari's reading (NPS)?

    • Many marine invertebrates have excellent fossil records
    • Land fossils are younger than 66 million years, so they say little
    • The sea had extinctions just once
    • Sea animals caused the extinctions

  14. Species usually last a few million years, yet NPS calls five events mass extinctions. What sets those five apart, by Bo's reading?

    • They are the sole times a species became extinct
    • Extinction rates spiked far above the usual rate for a short time
    • Before them, species did not become extinct
    • They each lasted over 100 million years
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The geologic time scale and the great extinctions

Answer Key - Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

  1. Branching tree that narrows, then spreads out again. A classmate says mass extinctions show life on Earth keeps shrinking. Which reply fits the NPS evidence, by Esme's reading?

    • Correct; variety has dropped since the first extinction
    • Correct; each extinction left fewer groups for good
    • Variety stays the same through each extinction
    • Variety drops sharply, then bursts of new species rebuild it

  2. Read this first

    The Big Five (NPS)

    ExtinctionAbout whenSpecies lost
    end-Ordovician444 million years ago86%
    Late Devonian372 million years ago75%
    end-Permian251.9 million years ago96%
    end-Triassic200 million years ago80%
    end-Cretaceous66 million years ago76%

  3. Why is the end-Cretaceous the extinction scientists tie to an asteroid, by Jun's reading (NPS)?

    • Its rocks hold flood basalts from that time
    • Glacier deposits from that time cover much of the poles
    • It is the oldest of the Big Five
    • A huge impact crater of the same age has been found

  4. Eras (USGS)

    EraBeganEnded
    Paleozoic541 million years ago251.9 million years ago
    Mesozoic251.9 million years ago66 million years ago
    Cenozoic66 million years agotoday

  5. The Paleozoic lasted about 289 million years, the Mesozoic about 186 and the Cenozoic 66 so far (USGS). About what share of the last 541 million years is the Cenozoic, by Luz's math?

    • About 53%
    • About 66%
    • About 34%
    • About 12%

  6. The Big Five (NPS)

    ExtinctionAbout whenSpecies lost
    end-Ordovician444 million years ago86%
    Late Devonian372 million years ago75%
    end-Permian251.9 million years ago96%
    end-Triassic200 million years ago80%
    end-Cretaceous66 million years ago76%

  7. The end-Ordovician (444) and end-Cretaceous (66 million years ago) are the first and last of the Big Five. On average, about how far apart are the five, by Milo's math?

    • About 76 million years, from dividing by 5
    • About 95 million years
    • About 378 million years
    • About 95 thousand years

  8. NPS lists several suggested causes for the Late Devonian extinction about 372 million years ago. Which statement fits, by Pia's reading?

    • An asteroid impact is the settled cause
    • Flood basalts are the settled cause
    • It is a dating error, and no extinction happened
    • No single cause has strong evidence yet

  9. Four evidence cards, labeled A to D. Which evidence would most strongly support an asteroid cause for an extinction layer, by Ren's reading?

    • A thick stack of flood basalts of the same age
    • An iridium layer and a crater of the same age
    • Fewer fossils above the layer, by itself
    • Glacier deposits just below the layer

  10. The Big Five (NPS)

    ExtinctionAbout whenSpecies lost
    end-Ordovician444 million years ago86%
    Late Devonian372 million years ago75%
    end-Permian251.9 million years ago96%
    end-Triassic200 million years ago80%
    end-Cretaceous66 million years ago76%

  11. NPS: the end-Triassic extinctions came over some time, linked to eruptions along rifts as the Atlantic opened. What does this suggest, by Tala's reading?

    • The Atlantic opened in the last million years
    • Each mass extinction took a single day
    • An asteroid opened the Atlantic
    • A mass extinction can unfold over a stretch of time

  12. Which summary of the end-Cretaceous fits NPS, by Zee's reading?

    • An asteroid impact, 76% of species lost, then mammals flourished
    • Flood basalts, 96% of species lost, then trilobites spread
    • An asteroid impact, then variety stayed low
    • A glaciation, 86% of species lost, then stony corals spread

  13. Why does most of what we know about the Big Five come from sea life, by Ari's reading (NPS)?

    • Many marine invertebrates have excellent fossil records
    • Land fossils are younger than 66 million years, so they say little
    • The sea had extinctions just once
    • Sea animals caused the extinctions

  14. Species usually last a few million years, yet NPS calls five events mass extinctions. What sets those five apart, by Bo's reading?

    • They are the sole times a species became extinct
    • Extinction rates spiked far above the usual rate for a short time
    • Before them, species did not become extinct
    • They each lasted over 100 million years