My Science Box

Sources
The geologic time scale used in this lesson was based on information from the International Commission on Stratigraphy and on Wikipedia.

The lesson itself was inspired by several other similar lessons including one by Judy Scotchmoor called “What Came First?” and a series of lessons by the Kentucky Geological Survey called It’s About Time.

If you don’t like the style of the Geologic Time Scale provided here, try these:

• From the UC Museum of Paleontology. Definitely check out their geologic time machine where you can explore each period, era and eon in greater detail.
• From the Geological Society of America. This version has the greatest level of detail I have seen.
• From the British Geological Society.
• From the Association of Professional Geoscientists of Ontario.
• From geology.com.

For more information on the geologic time scale, see:

• The USGS provides a great, short overview of geologic time.
• So does the Kentucky Geological Survey.

Standards
Grade 7
Earth and Life History (Earth Sciences)
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.
d.    Students know that evidence from geologic layers and radioactive dating indicates Earth is approximately 4.6 billion years old and that life on this planet has existed for more than 3 billion years.
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.