Unit 9 Geological Time Unit 9 Title Page • Geological Time – Unit 9 • Earth Space Science • 6th grade Essential Questions: How do scientists determine the age of rocks and fossils? How do humans affect change on earth? Essential Questions: How do scientists determine the age of rocks and fossils? How do humans affect change on earth? Essential Questions How do scientists determine the age of rocks and fossils? How do humans affect change on earth? Sunshine State Standards SC.6.E.6.1 Describe and give examples of ways in which Earth's surface is build up and torn down by physical and chemical weathering, erosion, and deposition. Sunshine State Standards SC.7.E.6.6 Identify the impact that humans have had on Earth such as deforestation, urbanization, desertification, erosion, air and water. Sunshine State Standards SC.7.E.6.3 Identify current methods for measuring the age of the Earth and its parts including the law of superposition and radioactive dating. Sunshine State Standards SC.7.E.6.4 Explain and give examples on how physical evidence supports scientific theories that the Earth has evolved over geologic time due to natural processes. Sunshine State Standards • SC7.E.6.7 Recognize the heat flow and movement of the earth causes earthquakes, volcanic eruptions, and creates mountains over basins. Earth’s History 1. How old is 1. 4,600,000,000 the earth? years (give or take) Earth’s History 2. What is 2. A time scale of Geologic the history of the Time? earth and life on it Earth’s History 3. What are 3. the theories A collapsing cloud of dust became the solar about earth system forming? Earth was one of several clumps of stuff that formed The biggest clump became the sun Earth’s History 4. 4. Describe A. The surface was hot with no earth’s early oceans history. B. Gasses from volcanoes formed an atmosphere C. Some gasses cooled to form liquids and a worldwide ocean D. 3,800,000,000 years ago, small landmasses formed in the oceans E. Life started in the oceans Life on Earth 5. 5. What is a Fossils are remains or evidence of an fossil? organism that lived in the past Usually an organism that had been buried in sediments Could be footprints, imprints, petrified, etc. Used to show how organisms have changed over time Earth’s History 6. 6. Describe life The earth began to settle down on earth 2 from its rumbling, destructive origins. million years • Changes happened more slowly since then ago. • Processes of Change a) Weathering – rocks are broken down into smaller particles b) Erosion – small rock particles are carried away by wind, water, ice, gravity, etc. c) Deposition – buildup of sediment in low places d) Uplift – parts of the earth are pushed up to form mountains or plateaus Geological Time Scale 7. What does 7. The rocks contain records of geological time. it mean, “ Geologic time is divided record in into stages based on the rocks?” important changes of the rocks. The layers of sedimentary rock contain information Geological Time Scale 8. What is 8. Relative age is the age of rocks determined by relative age? position of the layers. Geological Time Scale 9. What is the 9. The principle of superposition principle of states that the younger layers of rock superposition? form layers on top of older rocks. Unconformity, or a line between rock layers that show a break in geological time does occur. Rock layers are horizontal before they deform; faults and igneous intrusions are younger than layers they cut across. Geological Time Scale 9A: Sketch Geological Time Scale 10.What is 10. Absolute Age is an approximate age in years of a rock as determined absolute by radiometric dating age? • isotopes decay into more stable atoms • half-life – time it takes for half of a sample to decay Divisions of Geological Time Scale 11. What is 11. Eras are one of the larger units of geologic time ( eons are the largest) an era? Include 4 major divisions: Precambrian, Paleozoic, Mesozoic, and Cenozoic Divisions of Geological Time Scale 12. What is 12. A period of time is a a period subdivision of a of time? geological era; based upon types of life Divisions of Geological Time Scale 13. What is An epoch is a 13. an epoch? subdivision of a geological time period. The Eras: Geological Time Scale 14. The 14. •4,600 to 640 million years ago Precambrian • began with the formation of Era. the earth • Cyanbacteria – one of the oldest life forms on Earth which first appeared 3,500 million years ago; began to release oxygen into the atmosphere. • first many-celled organisms over 1,000 million years ago Paleozoic Era 15. Paleozoic Era – 640 to 245 15. Describe million years ago the • First animals with backbones in Paleozoic oceans era. • Simple plants on land about 430 million years ago arthropods (bugs) on land about 400 million years ago • Ended with a mass extinction The Mesozoic Era 16. 16. Mesozoic Era – 245 to 66 million years ago Describe • dinosaurs and flowering the plants Mesozoic • most of earth was warm & Era wet • ended with a mass extinction The Cenozoic Era 17. Describe the Cenozoic Era? 17. Cenozoic Era – 66 million years ago to now • mammals began to take over • cooler and drier • several ice ages • ends with ?