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 Chapter 14: Geologic Time

Discovering the Past Imagine what Texas was like millions of years ago. What animals might have been roaming around the spot where you now sit? Can you picture a Tyrannosaurus rex roaming the area that is now Dinosaur National Park? The animals and plants that once inhabited your region might have left some clues to their identity–fossils. Scientists use fossils to piece together what Earth looked like in the geologic past. Fossils can help determine whether an area used to be dry land or was underwater. Fossils can help uncover clues about how plants and animals have evolved over the course of time. Using the resources of the Internet and by sharing data with your peers, you can start to discover how North America has changed through time.

How has your area changed over geologic time?

How might the area where you are now living have looked thousands or millions of years ago? Do you think the types of animals and plants have changed much over time? Form a hypothesis concerning the change in organisms and geography from long ago to the present day in your area.

Goals Gather information about fossils found in your areas. Communicate details about fossils found in your area. Synthesize information from sources about the fossil record and the changes in your area over time.   Data Sources Weblinks View Student Data

Plan Determine the age of rocks that make up your area. Were they formed during the Precambrian time, the Paleozoic Era, the Mesozoic Era, or the Cenozoic Era? Gather information from the links here or the library about the fossil plants and animals found in your area during one of these geologic time periods. Find information on where and how the fossil organisms lived. Do Obtain descriptions of other fossils in your area from the sites listed here. Complete a data table in your Science Journal like the one below. Add any additional information that you think is important. Post the information in the data table below.

What present-day relatives of prehistoric animals or plants exist in your area? How have the organisms in your area changed over time? Is your hypothesis supported? Why or why not? What other information did you discover about your area's climate or environment from the geologic time period you investigated? Describe the plant and animal fossils that have been discovered in your area. What clues did you discover about the environment of your fossil organisms? How do these compare to the environment of your area today? Using information posted for this activity, infer from the fossil organisms found in your area what the geography and climate were like during the geologic time period you chose.

Results

Fossil Name Location Period or Epoch How or Where Fossil Lived Additional Information Fossil Name Location Period or Epoch How or Where Fossil Lived Additional Information Fossil Name Location Period or Epoch How or Where Fossil Lived Additional Information Fossil Name Location Period or Epoch How or Where Fossil Lived Additional Information * City: * State: Select Your State Alabama Alaska Arizona Arkansas California Colorado Connecticut Delaware District of Columbia Florida Georgia Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia Washington West Virginia Wisconsin Wyoming Not Applicable * School: *required