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End of Year Review Geologic Evidence of Change Over Time

End of Year Review Geologic Evidence of Change Over Time. Wake County 8 th Grade Science Curriculum. Fossil: evidence of past life preserved in rock; Different kinds of fossils are: Petrified fossil: minerals replace all or part of an organism. Change Over Time Geologic Evidence.

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End of Year Review Geologic Evidence of Change Over Time

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  1. End of Year ReviewGeologic Evidence of Change Over Time Wake County 8th Grade Science Curriculum

  2. Fossil: evidence of past life preserved in rock; Different kinds of fossils are: Petrified fossil: minerals replace all or part of an organism Change Over TimeGeologic Evidence en.wikivisual.com You can see the rings. www.alaska.edu

  3. Change Over TimeGeologic Evidence Mold: a hollow area in sediment in the shape of an organism or part of an organism; formed when the organism makes an indentation that turns to rock over time Cake mold www.ammonoid.com

  4. Change Over TimeGeologic Evidence Cast: a solid copy of the shape of an organism; made by filling in a mold with minerals that later turn to rock. esp.cr.usgs.gov Mold Cast

  5. Change Over TimeGeologic Evidence Carbon film: an extremely thin coating of carbon on rock; made when an organism is squeezed by rock until only carbon remains www.geology.ohio-state.edu

  6. Change Over TimeGeologic Evidence Trace fossil: evidence of activities of ancient organisms; may be tracks, burrows, nest, or trail igs.indiana.edu Fossil burrow Fossil tracks

  7. Change Over TimeGeologic Evidence Amber: a hardened resin, or sap, of evergreen trees; organisms that get trapped in the sticky substance becomes part of the rock pixdaus.com www.ambermine.com

  8. Change Over TimeGeologic Evidence Frozen remains: organisms caught in ice or snow Adult mammoth Frozen baby mammoth www.cryptomundo.com flickr.com

  9. Change Over TimeGeologic Evidence Fossil record: the complete body of fossils that shows how species and ecosystems change over time www.rockandwater.com anthropology.net images.mooseyscountrygarden.com

  10. Change Over TimeGeologic Evidence How do fossils give us the age of organisms that lived in the past? Is this fish fossil a few thousand years old or a few billion years old? www.treasure-hunting-team.com

  11. Change Over TimeGeologic Evidence Dating Rocks and Fossils Relative Dating: uses information about rock layers and the fossil record to determine the age relationships between rocks Absolute Dating: any method of measuring the age of an event or object in years

  12. ESSENTIAL QUESTION #1 • What is the Law of Superposition?

  13. Change Over TimeRelative Dating Law of Superposition: states that the oldest rocks lie on the bottom and the youngest rocks are on top of any undisturbed sequence of sedimentary rocks. media-2.web.britannica.com

  14. Which can most likely be concluded about the top layer of rock seen in an undisturbed cliff wall? The top layer is older than layers located farther down the cliff. The top layer is younger than layers located farther down the cliff. The top layer contains more fossils than layers located farther down the cliff. The top layer contains fewer fossils than layers located farther down the cliff.

  15. Which can most likely be concluded about the top layer of rock seen in an undisturbed cliff wall? The top layer is older than layers located farther down the cliff. The top layer is younger than layers located farther down the cliff. The top layer contains more fossils than layers located farther down the cliff. The top layer contains fewer fossils than layers located farther down the cliff.

  16. Change Over TimeRelative Dating The fossils in layer 3 are “relatively” the same age. Which layers are older than layer 3? 1 and 2 Which layers are younger than layer 3? 4,5,6,and 7

  17. ESSENTIAL QUESTION #1 • What is the Law of Superposition? • Law of Superposition: states that the oldest rocks lie on the bottom and the youngest rocks are on top of any undisturbed sequence of sedimentary rocks.

  18. Based on the Law of Superposition, what can be concluded about fossils? Fossils give clues about the past climate patterns. Fossils form from the hard parts of organisms. The oldest fossils are found in the lowest rock layers. The most recent fossils were advanced organisms.

  19. Based on the Law of Superposition, what can be concluded about fossils? Fossils give clues about the past climate patterns. Fossils form from the hard parts of organisms. The oldest fossils are found in the lowest rock layers. The most recent fossils were advanced organisms.

  20. ESSENTIAL QUESTION #2 • How can an unconformity be used as evidence for geologic evolution?

  21. Change Over TimeRelative Dating Since the top of layer 5 and layer 6 are at the same level, are these two layers the same age? Why or why not?

  22. Change Over TimeRelative Dating No, they are not the same age. Layer 5 is older than layer 6. Unconformity: gaps in the rock record created when older rock is worn away then new rock is layered over it. You can see that parts of the older layers are missing.

  23. ESSENTIAL QUESTION #2 • How can an unconformity be used as evidence for geologic evolution? • An unconformity can be used to determine relative age of rock layers.

  24. Which does a scientist most likely consider when studying the relative ages of rock layers in a canyon wall? Chemical weathering Current climate Amount of daily rainfall Law of Superposition

  25. Which does a scientist most likely consider when studying the relative ages of rock layers in a canyon wall? Chemical weathering Current climate Amount of daily rainfall Law of Superposition

  26. ESSENTIAL QUESTION #3 • How is the age of the earth determined?

  27. Change Over TimeAbsolute Dating • When magma or lava hardens, new rock is formed. • When new rock is formed, some elements’ isotopes are radioactive. www.kilaueaadventure.com

  28. Change Over TimeAbsolute Dating • Isotope: an atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (thus a different atomic mass) • Parent isotope: an atomic nucleus that is undergoing decay (Tritium H-3) Daughter isotope: the stable isotope that results from radioactive decay (Helium-3) www.radiation-scott.org

  29. Change Over TimeAbsolute Dating • Tritium is radioactive. • It “decays” by losing an electron from one of the neutrons. • Radioactive decay: the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element. • The neutron becomes a proton increasing the atomic number from one (Hydrogen) to two (Helium) Parent isotope Daughter isotope www.impcas.ac.cn

  30. Change Over TimeAbsolute Dating • Half-life: the time needed for half of a sample of radioactive substance to undergo radioactive decay (Tritium has a half-life of 12.5 years)

  31. Change Over TimeAbsolute Dating www.kgs.ku.edu

  32. Change Over TimeAbsolute Dating • All radioactive elements have a specific half-life library.thinkquest.org

  33. Change Over TimeAbsolute Dating • After measuring the amount of parent isotopes and daughter isotopes in a rock, scientists use mathematical calculations to determine the rock’s age. • These calculations are based on the half-life of the isotopes. • When the rock is dated, we can know exactly how long ago the organism was alive.

  34. Change Over TimeAbsolute Dating • Radioactive Dating: the process by which the age of a rock is determined by measuring the amount of radioactive isotopes present in the rock or rock sample eapbiofield.wikispaces.com

  35. ESSENTIAL QUESTION #3 • How is the age of the earth determined? • Class discussion.

  36. ESSENTIAL QUESTION #4 • How has the geology of the Earth changed over time?

  37. Continental Drift Continental Drift Theory: theory that states that the gradual shifting of Earth’s plates causes continents to change their global positions over time.

  38. Plate Tectonics • Correlation: the matching up of rock layers from different locations • Can use minerals in rock layers or fossils physics.uwstout.edu www.answers.com

  39. ESSENTIAL QUESTION #4 • How has the geology of the Earth changed over time? • Class discussion.

  40. ESSENTIAL QUESTION #5 • How has the Earth been impacted by major geological events?

  41. Which is the best evidence that two continents were once connected? They have similar types of rocks and fossils. They are in the same stage of succession. They exist along the same line of latitude. They have the same climate.

  42. Which is the best evidence that two continents were once connected? They have similar types of rocks and fossils. They are in the same stage of succession. They exist along the same line of latitude. They have the same climate.

  43. Plate Tectonics Plate tectonics is the theory that explains how large pieces of the Earth’s outermost layer called tectonic plates move and change shape

  44. Plate Tectonics Cause of Plate Movements: Heat from the core sets up convection currents within the mantle. As the mantle moves, it moves the plates above. mediatheek.thinkquest.nl

  45. Plate TectonicsAll Over the World cimss.ssec.wisc.edu

  46. ESSENTIAL QUESTION #5 • How has the Earth been impacted by major geological events? • Plate tectonics has caused continents to move to different climates. • Movement of plates cause mountains to build, earthquakes, and volcanoes. • What other major geological events can you think of?

  47. ESSENTIAL QUESTION #6 • How have mechanical and chemical weathering impacted the earth?

  48. Weathering Mechanical weathering: is the erosion of rocks and soil caused by wind, water, or ice freezing inside rocks WATER  soilerosion.net www.kidsgeo.com www.flickr.com WATER FREEZING  WIND 

  49. Weathering Chemical weathering: is the erosion of rocks and soil caused by chemical reactions mail.colonial.net edutel.musenet.org Pollutants causing acid rain that will react to minerals in natural rock or statues carved from rock Iron in rock combining with oxygen to form iron oxide (rust)

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