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Earth’s History Test Study Guide E.8.7.1-4 8th Grade Science Name ____________________________________________ Period__________ E.8.7.2 Study rock cycle foldable and complete the following diagram and table. 1. Magma Metamorphic Igneous Sedimentary Sediment Type of Rock Description of Rock Sedimentary Forms in layers, may contain fossils Metamorphic Can look like layers in ribbons, may be banded, or marbled Igneous Intrusive-hard, dense, may have colors Extrusive-light, porous, or glassy 2. How is magma important to the rock cycle? Magma is molten rock that helps to drive the rock cycle. When it reaches the surface, it is lava. All types of rock can melt to form magma. 3. What type of rock are fossils found in and explain why? Fossils are found in sedimentary rock because organisms like plants and animals are trapped between the layers, die, and over time become fossils. 4. What is the difference between intrusive and extrusive igneous rock? Intrusive igneous rock hardens slowly below Earth’s surface. Rock is hard, dense, and may have speckles of color. Extrusive rock cools and hardens rapidly above Earth’s surface. It is light and porous, or it may be glassy. E.8.7.1&3. 5. Diagram Relative Dating Principle/Law Brief Definition When sedimentary rock Law of Superposition forms, younger layers are deposited on top of older deposited layers. Sedimentary rock is Law of Original Horizontality deposited horizontally. If they are tilted, folded, or broken, it happened later. Law of Cross-cutting If an igneous intrusion or a Relationships fault cuts through a rock, it is younger than the rock it cuts through. 6. The process in which sediments are made & picked up then moved to another place by ice, water, wind, or gravity. Weathering and erosion 7. The process, making sedimentary rock, in which particles of sediment begin to stick to each other - they are cemented together by clay, or by minerals and changes to sedimentary rock. Compaction and cementation 8. List the processes necessary to form each type of rock:. Type of Rock Key words for each type of rock & processes that form them Sedimentary Layers, compaction and cementation of sediment, weathering and erosion Metamorphic Heat and pressure, ribbon-like Igneous Magma cools, crystallization, hardens, solidification 9. What is the difference between absolute dating and relative dating. Absolute dating uses scientific methods to determine how many years old something is. Relative dating is used to determine if one thing is younger or older than another. 10. Define the Law of Superposition. When sedimentary rock forms, younger layers are deposited on top of older deposited layers. 11. Define the Law of Original Horizontality. Sedimentary rock is deposited horizontally. If they are tilted, folded, or broken, it happened later. 12. Define the Law of Cross-cutting Relationships. If an igneous intrusion or a fault cuts through a rock, it is younger than the rock it cuts through. 13. What three characteristics are necessary for an index fossil. 1. They are abundant 2. They are wide-spread; found in multiple locations or outcrops 3. They are short-lived or found only in one layer The is the best index fossil. It is abundant, widespread, and short-lived. 14. Circle the fossil that would make the BEST index fossil and then explain why. Use the above diagram to answer questions #15-19. 15. Which is the youngest layer of rock? R is the youngest layer of rock because it is on the top 16. Which is the oldest layer of rock? The oldest Layer of rock is Layer I, because it is on the bottom. 17. Which law explains #15 and #16? The Law of Superposition 18. What is H and how did it form? ? H is an igneous intrusion. A crack, or fault cut through the rock. The fault filled with magma from below Earth’s surface, which hardened to form igneous rock. 19. Explain the relative age relationship between H and I. H is younger than I, because Layer I rock had to be there first before H could appear and cut through. E.8.7.3-4 20. What can you say about the characteristics of Mississippi during the Paleozoic Era when you consider its state fossil, the prehistoric whale? Mississippi was most likely under water during the Paleozoic Era, explaining why marine fossils, such as the prehistoric whale have been found. 21. Use your notes to complete the table. Name of Era Life Forms Found Major Events Years Span Oceans 543 mya – 249 Marine Life; “Age of formed;Pangea mya Paleozoic Era the Fish”; Trilobites, formed; Largest shellfish, fish mass extinction at the end of the Paleozoic Era; “Age of the Reptiles Pangea broke apart; 248 mya-65 and dinosaurs”; Dinosaurs became mya birds, trees, forests extinct due to mass Mesozoic Era appear extinction at the end of the Mesozoic Era; evidence of meteorites (iridium). “ Age of the Ice Age, ice sheets 65 mya- Mammals”; Large advance; plate Present Cenozoic Era mammals, humans movements form appear mountains, volcanoes, earthquakes “Age of Bacteria”; First life, 543 mya to 4 one-celled, bacteria, photosynthesis bya Precambrian seaweed, jellyfish, releases oxygen worms, algea leading to organisms to evolve 22. Order divisions of the geologic time scale from smallest to largest. Epochs, Periods, Eras, Eons. 23. During which era did the land mass Pangea form? When did it break apart? Pangea formed during the Paleozoic Era, and broke apart during the Mesozoic Era. 24. List events that lead to mass extinction. Volcanic eruptions, meteorite impacts, ice age. For questions 25- 27, use figure Z. 25. Put A-E in order of oldest to youngest. B, C, A, D, E. Figure Z 26. What Law helps you to determine the order of the layers? Law of Superposition 27. What law explains A in the diagram? Law of Cross-cutting relationships Unconformity is 28. here fault a. Correlate the rock layers in the out crop b. Circle the rock layers that show that unconformity has occurred c. What does G-H represent a fault 29. Mark an X to classify the events in history as shaping evolution gradually or through mass extinction. Event Gradual Mass Extinction Climate change X X Volcanic eruptions X Natural selection X Speciation X Meteor strikes X Ice age X Old Content to review (be sure to look at old foldables & study guides) • Label the structure of DNA • Differences between mitosis / meiosis • Advantages & disadvantages of sexual & asexual reproduction • Punnett Squares • Genetic engineering & selective breeding • Adaptations, natural selection, Darwin’s finches *see foldable • Speciation • Anatomical structures .
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