The Sixth Great Mass Extinction

By Wagler, Ron | Science Scope, March 2012 | Go to article overview

The Sixth Great Mass Extinction


Wagler, Ron, Science Scope


Five past great mass extinctions have occurred during Earth's history. Humanity is currently in the midst of a sixth, human-induced great mass extinction of plant and animal life (e.g., Alroy 2008; Jackson 2008; Lewis 2006; McDaniel and Borton 2002; Rockstrom et al. 2009; Rohr et al. 2008; Steffen, Crutzen, and McNeill 2007; Thomas et al. 2004; Wake and Vredenburg 2008; Zalasiewicz et al. 2010). This article explains the first five great mass extinctions, the current great mass extinction, and the human activities and rates of species extinction associated with the current extinction. The sixth great mass extinction can be used to teach students about environmental change and its impacts and extinction. The topics and resources discussed here can also be aligned to all seven of the crosscutting concepts in A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (NRC 2011, 4-1-4-2), which include examples such as cause and effect: mechanism and explanation; scale, proportion, and quantity; systems and system models; and stability and change.

Earth's past great mass extinctions

The Earth is over 4.5 billion years old (Dalrymple 2001), and during the planet's history, five past great mass extinctions have occurred (Erwin 2001; Jablonski 1995). During all of these past great mass extinctions, there was an enormous loss of life in a short time (see Figure 1). The first great mass extinction occurred approximately 439 million years ago; the fifth took place approximately 65 million years ago (Erwin 2001; Jablonski 1995). The fifth great mass extinction is the most well known to the general public because it involved the extinction of the non-avian dinosaurs (Wake and Vredenburg 2008) and the survival of the only existing living group of dinosaurs, the birds. The most destructive past great mass extinction was the Permian-Triassic extinction, in which 95% of Earth's species went extinct (Erwin 2001; Jablonski 1995)

FIGURE 1 Earth's past great mass extinctions

Name                 Number  Date of      Cause of extinction
                             extinction

Ordovician-Silurian  1st*    ~439         Fluctuations in sea level;
extinction                   million      extensive glaciations;
                             years ago    global warming

Late Devonian        2nd*    ~364         Global cooling after
extinction                   million      bolide (large exploding
                             years ago    meteor) impacts may have
                                          been responsible.

Permian-Triassic     3rd     ~251         Causes are debated. The
extinction                   million      leading candidate is flood
                             years ago    volcanism. This led to
                                          profound climate change.
                                          The volcanism may have
                                          been initiated by a bolide
                                          impact.

End Triassic         4th     ~199-214     "Opening of the Atlantic
extinction                   million      Ocean by seafloor
                             years ago    spreading related to
                                          massive lava floods that
                                          caused significant global
                                          warming."

Cretaceous-Tertiary  5th     ~65 million  Causes are debated.
extinction                   years ago    Possible causes include a
                                          giant asteroid impact in
                                          the Gulf of Mexico and
                                          climatic changes resulting
                                          from volcanic floods in
                                          India.

Name                 Loss of life 1


Ordovician-Silurian  "Approximately 25% of the
extinction           families and nearly 60% of
                     the genera of marine
                     organisms were lost. … 

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

The Sixth Great Mass Extinction
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.