1. Chapter 3 : Earth Science The Rock and Fossil Record

2. Earth Science : Chapter 3.1 Earth’s Story and Those Who First Listened

3. Objectives Compareuniformitarianism and catastrophism. Describehow the science of geology has changed over the past 200 years. Explainthe role of paleontology in the study of Earth’s history.

4. The Principle of Uniformitarianism Scientist James Hutton author of Theory of the Earth proposed that geologic processes such as erosion and deposition do not change over time. Uniformitarianism the idea that the same geologic processes shaping the Earth today have been at work throughout Earth’s history.

6. Uniformitarianism Versus Catastrophism Hutton’s theories sparked a scientific debate by suggesting The Earth was much older than a few thousand years, as previously thought. A few thousand years was not enough time for the gradual geologic processes that Hutton described to have shaped the planet. Catastophism Principle that states that geologic change occurs suddenly.

7. Catastrophism was geology’s guiding principle until the work of geologist Charles Lyell caused people to reconsider uniformitarianism. Lyell published Principles of Geology in the early 1830s. Armed with Hutton’s notes and new evidence of his own, Lyell successfully challenged the principle of catastrophism. A Victory for Uniformitarianism

8. Modern Geology -- A Happy Medium During the late 20th century Scientists such as Stephen J. Gould challenged Lyell’s uniformitarianism. They believed that catastrophes occasionally play an important role in shaping Earth’s history. Today Scientists realize that most geologic change is gradual and uniform, but catastrophes that cause geologic change have occurred during Earth’s long history.

9. Paleontology -- The Study of Past Life The history of the Earth would be incomplete without knowledge of the organisms that have inhabited our planet and the conditions under which they lived. Paleontology Science involved with the study of past life Paleontologist Study fossils, which are the remains of organisms preserved by geologic processes.