8. Extinction Theories - Sources and Standards

Sources
There are many excellent websites that discuss the K-T extinction:

• The UC Museum of Paleontology has a superb discussion of the ongoing scientific debate.
• Wikipedia offers a great deal of information about both of the major theories and the evidence in favor of each.
• PBS also provides a balanced discussion of the major theories.
• Finally, the BBC has a good article about the dating of the Chicxulub crater.

Standards
Grade 7
Earth and Life History (Earth Sciences)
4. Evidence from rocks allows us to understand the evolution of life on Earth. As a basis for understanding this concept:
a. Students know Earth processes today are similar to those that occurred in the past and slow geologic processes have large cumulative effects over long periods of time.
b. Students know the history of life on Earth has been disrupted by major catastrophic events, such as major volcanic eruptions or the impacts of asteroids.
e. Students know fossils provide evidence of how life and environmental conditions have changed.
g. Students know how to explain significant developments and extinctions of plant and animal life on the geologic time scale.