Module 3 Earth and Life.pdf

Understanding Earth's Dynamic Processes and History Introduction to Earth's Dynamic Processes Earth is a dynamic planet constantly changing. These changes shape landforms and influence the evolution of organisms. Geologists study rocks and fossils to understand Earth's history. Learning...

Understanding Earth's Dynamic Processes and History Introduction to Earth's Dynamic Processes Earth is a dynamic planet constantly changing. These changes shape landforms and influence the evolution of organisms. Geologists study rocks and fossils to understand Earth's history. Learning Objectives Explain how the continents drifted away from one another. Cite pieces of evidence that support the continental drift theory. Explain how plate movements form various landforms. Describe seafloor spreading and ocean basin evolution. Understand the formation and dating of stratified rocks. Interpret Earth's history using the geologic time scale.  Theories of Earth's Landscape Formation Continental Drift Theory Seafloor Spreading Hypothesis Plate Tectonics Theory Continental Drift Theory Proposed by Alfred Wegener in 1912. Suggests continents were once part of a supercontinent called Pangaea. Continents drifted to their current locations over time. Evidence for Continental Drift Fit of the continents. Similar fossils found on different continents. Rock and mountain correlation. Paleoclimate data.  Seafloor Spreading Hypothesis Proposed by Harry Hess in 1945. Ocean floor features like ridges and trenches discovered using SONAR. Magma rises at mid-oceanic ridges, creating new seafloor. Evidence for Seafloor Spreading Age of the seafloor: younger near mid-oceanic ridges, older near continents. Magnetic striping of the seafloor due to polar reversals. Plate Tectonics Theory Unifies concepts from continental drift and seafloor spreading. Earth's surface is divided into large tectonic plates. Movement of plates driven by convection currents in the mantle.  Types of Plate Boundaries Convergent: plates collide. Divergent: plates move apart. Transform: plates slide past each other. Concentration of earthquakes and volcanic eruptions at boundaries. Formation of Landforms Mountains and volcanoes form at convergent boundaries. Rift valleys form at divergent boundaries. Earthquakes occur at transform boundaries. Evolution of Ocean Basins Ocean basins develop through the Wilson cycle. Stages: Embryonic, Juvenile, Mature, Declining, Terminal, Suturing. Involves breaking up, drifting, and colliding of continents.  Formation of Stratified Rocks Sedimentary rocks form through stratification. Layers form by deposition, compaction, and cementation. Provide records of past climates and environments.  Fossils and Their Importance Fossils are remains or traces of organisms preserved in rocks. Form in sedimentary rocks through burial and mineralization. Index fossils help date rock layers and understand Earth's history. Relative Dating Methods Determines the order of past events without exact dates. Principles: superposition, lateral continuity, original horizontality, cross-cutting, inclusion, unconformity, faunal succession.  Absolute Dating Methods Determines the exact age of rocks and fossils. Uses radioactive isotopes and their half-lives. Example: Uranium-238 decays to Lead-206 with a half-life of 4.47 billion years. Geologic Time Scale Record of life-forms and events since Earth's formation. Divided into eons, eras, periods, and epochs. Based on major events like the appearance or disappearance of life-forms. Interpreting Earth's History Rocks and fossils provide clues about past climates and environments. Geologic time scale helps understand the sequence of events. Major events include mass extinctions and the rise of new life-forms.  Probing Questions How do fossils support the theory of continental drift? What evidence supports the seafloor spreading hypothesis? How do plate movements create different landforms? Why are index fossils important in geology? Conclusion Earth's dynamic processes shape its landforms and history. Theories like continental drift, seafloor spreading, and plate tectonics explain these processes. Rocks and fossils are crucial in understanding Earth's past. Further Reading and Resources "The Origin of Continents and Oceans" by Alfred Wegener. "History of Ocean Basins" by Harry Hess. Online resources: USGS, NASA Earth Science.