Specific rock formations are indicative of a particular type of environment existing when the rock was being formed.
For example, most limestones represent marine environments, whereas, sandstones with ripple marks might indicate a shoreline habitat or a riverbed.
By using this information from rock formations in various parts of the world and correlating the studies, scientists have been able to establish the geologic time scale.
This relative time scale divides the vast amount of earth history into various sections based on geological events (sea encroachments, mountain-building, and depositional events), and notable biological events (appearance, relative abundance, or extinction of certain life forms).
On a larger scale, even between continents, fossil evidence can help in correlating rock layers.
Materials: two sets of sequence cards in random order (set A: nonsense syllables; set B: sketches of fossils), pencil, paper Procedure Set A: 1) Spread the cards with the nonsense syllables on the table and determine the correct sequence of the eight cards by comparing letters that are common to individual cards and, therefore, overlap.
Extinction of species is common; most of the species that have lived on the earth no longer exist.
*Earth and Space Science: Fossils provide important evidence of how life and environmental conditions have changed.
The module is an integrated unit which addresses the following National Science Education Standards: *Science as Inquiry: Students develop the abilities necessary to do scientific inquiry identify questions, design and conduct scientific investigations, use appropriate tools and technologies to gather, analyze and interpret data, think critically and logically to make the relationships between evidence and explanations, communicate results, and use mathematics in all aspects of scientific inquiry.
*Life Science: Fossils indicate that many organisms that lived long ago are extinct.