Examining Mass Extinctions on Earth
Modified from an activity by Jennifer Cutraro and Holly Epstein Ojalvo
http://learning.blogs.nytimes.com/2011/04/06/will-it-happen-again-examining-mass-extinctions-on-earth/
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
What is a mass extinction, and why do some scientists think that human beings may be
responsible for the next one?
What do we know about the past extinctions, including their likely causes?
In this lesson, you will learn about the “Big Five” mass extinctions of the past:
1.
2.
3.
4.
5.
Late Ordovician
Late Devonian
End-Permian (sometimes called “Permian-Triassic”)
End-Triassic
End-Cretaceous (also known as “Cretaceous-Tertiary” or “K-T”)
Your group will become experts about one of these extinction events, and will then teach others
what you’ve learned.
Using the information provided, fill in the table on p. 2 and then answer the questions below.
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How do scientists know what they know about the event?
What evidence have they used to support their ideas?
Do scientists agree on the cause for this extinction?

What are two facts about this extinction event that make it significant in the history of life on
Earth (significant life forms that went extinct, new life forms that evolved after this
extinction, etc.)?
Extensions
 Make a drawing or other visual representation of three species that went extinct during
their event.
 Draw a map showing the location and names of the continents at that time.
 Make a pie chart of other graphic indicating the percentage of life on Earth that went
extinct at that time
1
Extinction
When?
Percentage of
organisms lost?
Kinds of organisms
that went extinct?
What did Earth look like then?
Possible causes of the
extinction?
Late
Ordovician
Late
Devonian
EndPermian
(“PermianTriassic”)
End-Triassic
EndCretaceous
(“K-T”)
2
3