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These major concepts are part of the Denver Earth Science Project's "Paleontology and Dinosaurs" module written for students in grades 7-10.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.INTRODUCTION Scientists have good evidence that the earth is very old, approximately four and one-half billion years old.Scientific measurements such as radiometric dating use the natural radioactivity of certain elements found in rocks to help determine their age.If certain fossils are typically found only in a particular rock unit and are found in many places worldwide, they may be useful as index or guide fossils in determining the age of undated strata.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.Sequencing the rock layers will show students how paleontologists use fossils to give relative dates to rock strata.Once students begin to grasp "relative" dating, they can extend their knowledge of geologic time by exploring radiometric dating and developing a timeline of Earth's history.
Although most attention in today's world focuses on dinosaurs and why they became extinct, the world of paleontology includes many other interesting organisms which tell us about Earth's past history.The Law of Superposition, which states that in an undisturbed horizontal sequence of rocks, the oldest rock layers will be on the bottom, with successively younger rocks on top of these, helps geologists correlate rock layers around the world.This also means that fossils found in the lowest levels in a sequence of layered rocks represent the oldest record of life there.By matching partial sequences, the truly oldest layers with fossils can be worked out.By correlating fossils from various parts of the world, scientists are able to give relative ages to particular strata. Relative dating tells scientists if a rock layer is "older" or "younger" than another.
The study of fossils and the exploration of what they tell scientists about past climates and environments on Earth can be an interesting study for students of all ages.