Unit 2 Test Review -Updated Key PDF

Unit 2 Test Review Radiometric Dating (ES.7.A) 1. Radiometric dating is a method used to determine the: ○ a) Relative age of rocks and minerals. ○ b) Absolute age of rocks and minerals. ○ c) Chemical composition of rocks and minerals. ○ d) Physical properties of roc...

Unit 2 Test Review Radiometric Dating (ES.7.A) 1. Radiometric dating is a method used to determine the: ○ a) Relative age of rocks and minerals. ○ b) Absolute age of rocks and minerals. ○ c) Chemical composition of rocks and minerals. ○ d) Physical properties of rocks and minerals 2. Which of the following is NOT a common radiometric dating method? ○ a) Carbon-14 dating ○ b) Potassium-Argon dating ○ c) Uranium-Lead dating ○ d) Nitrogen-14 dating 3. A key limitation of radiometric dating is: ○ a) The assumption of a constant rate of decay. ○ b) The need for precise measurement techniques. ○ c) The requirement of undisturbed rock samples. ○ d) All of the above. 4. What is the half-life of a radioactive isotope? ○ a) The time it takes for all of the isotope to decay. ○ b) The time it takes for half of the isotope to decay. ○ c) The time it takes for one atom of the isotope to decay. ○ d) The time it takes for the isotope to reach maximum stability. 5. How can scientists determine the age of a rock using radiometric dating? ○ a) By measuring the amount of parent isotope remaining. ○ b) By measuring the amount of daughter isotope produced. ○ c) By comparing the ratio of parent to daughter isotopes. ○ d) All of the above. 6. What are radiometric dating methods and how are they developed? ○ Radiometric dating methods are techniques used to determine the age of materials by measuring the decay of naturally occurring radioactive isotopes within them. ○ It provides EXACT ages of rock layers - looking at ratio of parent to daughter isotopes 7. Discuss the 4 different radiometric dating methods we discussed. Carbon-14 dating: ○ Suitable for organic materials like wood, bone, and plant fibers. ○ Short half-life (around 5,730 years) limits its use to relatively recent samples. Potassium-argon dating: ○ Primarily used for volcanic rocks due to the presence of potassium-bearing minerals. ○ Longer half-life of Potassium-40 allows for dating much older materials compared to carbon-14. Uranium-lead dating: ○ Best for extremely old rocks containing uranium isotopes. ○ Decay products (lead isotopes) are very stable and easily measured. Rubidium-strontium dating: ○ Similar to uranium-lead dating, used for very old rocks with high concentrations of rubidium. ○ Measures the decay of Rubidium-87 to Strontium-87. 8. How do these methods differ in terms of precision and reliability? ○ Know which type of rock each method is best used for. ○ Igneous rocks often used because they form with radioactive minerals that decay predictably 9. What are the limitations of using radiometric dating for calculating the ages of rocks? ○ Look back in the powerpoint to find limitations. ○ Radiometric dating CANNOT be used on sedimentary rocks  Relative Dating and Stratigraphy (ES.7.B) 10. The principle of superposition states that: ○ a) Older rock layers are found above younger rock layers. ○ b) Younger rock layers are found above older rock layers. ○ c) Rock layers are always horizontal. ○ d) Rock layers are always vertical. 11. Index fossils are used to: ○ a) Determine the absolute age of rock layers. ○ b) Correlate rock layers from different locations. ○ c) Measure the thickness of rock layers. ○ d) Identify the type of rock in a layer. 12.An unconformity represents: ○ a) A continuous period of sedimentation. ○ b) A gap in the rock record. ○ c) A period of rapid deposition. ○ d) A fault in the rock layers. 13. What is the principle of original horizontality? ○ a) Sedimentary rock layers are originally deposited horizontally. ○ b) Sedimentary rock layers are always tilted. ○ c) Sedimentary rock layers are always vertical. ○ d) Sedimentary rock layers are always folded. 14. What is the principle of cross-cutting relationships? ○ a) A rock layer is older than the fault that cuts through it. ○ b) A fault is older than the rock layer it cuts through. ○ c) Faults and rock layers are always the same age. ○ d) Faults and rock layers are never related. 15. What are the principles of stratigraphy and how are they applied in relative dating? ​ Principle of Superposition: ​ In an undisturbed sequence of sedimentary rock layers, the bottom layer is the oldest, and each layer above it is progressively younger. ​ Principle of Original Horizontality: ​ Sedimentary rock layers are initially deposited in horizontal layers due to gravity. ​ Principle of Lateral Continuity: ​ Sedimentary rock layers extend laterally in all directions until they thin out at the edge of the depositional basin. ​ Principle of Cross-Cutting Relationships: ​ Any geological feature that cuts through another rock layer must be younger than the layer it cuts through. ​ Principle of Inclusions: ​ Rock fragments contained within another rock must be older than the rock they are included in. 16. How are index fossils used to determine the chronological order of rock layers? Index fossils are used to determine the chronological order of rock layers by identifying fossils that lived for a very short period of time but were widespread geographically, meaning if the same index fossil is found in different rock layers, those layers must have formed around the same time, thus allowing geologists to correlate the age of different rock formations across various locations; essentially acting as a "marker" for a specific geological time period. Index fossils used to define and identify geologic periods EX) Trilobite fossil 17. Describe the characteristics that make a fossil a good index fossil. A good index fossil is characterized by having a wide geographic distribution, a short geological time range (meaning it existed for a relatively brief period), and distinctive features that make it easily recognizable EX) Trilobite fossil Geological Time Scale (ES.7.C) 18. The largest division of geological time is called a(n): ○ a) Era ○ b) Period ○ c) Epoch ○ d) Eon 19. The Mesozoic Era is often referred to as the: ○ a) Age of Mammals ○ b) Age of Reptiles ○ c) Age of Fish ○ d) Age of Invertebrates 20. What major event marked the end of the Cretaceous Period? ○ a) The formation of the supercontinent Pangaea. ○ b) The mass extinction of dinosaurs. ○ c) The beginning of the Ice Age. ○ d) The emergence of human beings. 21. The Cenozoic Era is characterized by: ○ a) The dominance of dinosaurs. ○ b) The rise of mammals and birds. ○ c) The formation of the first supercontinent. ○ d) The widespread occurrence of trilobites. 22. How do scientists determine the absolute age of rocks? ○ a) By studying the fossil record. ○ b) By measuring the thickness of rock layers. ○ c) By using radiometric dating techniques. ○ d) By analyzing the mineral composition of rocks. 23. Describe how relative and absolute dating methods are used to construct a model of the geological time scale. Relative dating methods, like stratigraphy, are used to establish the sequence of geological events (which layer is older than another) while absolute dating techniques, like radiometric dating, provide numerical ages for specific rock layers, allowing scientists to combine these data points to construct a comprehensive geological timescale, essentially placing events in chronological order with estimated ages for each period. 24. How do these methods contribute to our understanding of Earth’s 4.6-billion-year history? Think about what relative dating methods tell us and how that helps us shape our understanding? Relative dating methods are used to arrange geological events in sequential order Extinction market he destruction of a species due to environmental changes - and effects fossil record - These extinctions decrease biodiversity by wiping out species Mass extinction events (like the dinosaurs) mark the boundaries in many parts of geological time periods Sedimentation, Fossilization, and Speciation (ES.7.D) 25. Rapid burial is important for fossilization because it: ○ a) Increases the chances of decay. ○ b) Decreases the chances of decay. ○ c) Has no effect on fossilization. ○ d) Increases the chances of erosion. 26. The process by which new species arise is called: ○ a) Extinction ○ b) Adaptation ○ c) Speciation ○ d) Mutation 27. What is the role of sedimentation in the formation of fossils? ○ a) Sedimentation can bury organisms and protect them from decay. ○ b) Sedimentation can erode fossils and destroy them. ○ c) Sedimentation has no effect on fossilization. ○ d) Sedimentation only occurs in marine environments. 28. What type of rock is most likely to contain fossils? ○ a) Igneous rock ○ b) Metamorphic rock ○ c) Sedimentary rock ○ d) All rock types are equally likely to contain fossils. 29. Which of the following factors can influence the completeness of the fossil record? ○ a) The type of organism ○ b) The environment of deposition ○ c) The rate of sedimentation ○ d) All of the above 30. What is the process of sedimentation and how does it affect the fossil record? Sedimentation is the process where particles settle out of a fluid, like water, and deposit in layers, forming sediment which eventually becomes sedimentary rock; this process is crucial for fossil formation as it allows for the rapid burial of organisms, protecting their remains from decay and preserving them as fossils within the layers of sediment, essentially creating the fossil record. Sedimentation preserves fossils by rapid burial 31. Discuss the steps of the fossilization process. DEATH - organism may be enveloped by sediment like mud or sand BURIAL - Rapid burial is best to prevent decomp and scavengers LITHIFICATION - Sediments compacts under pressure - squeezing out water, encapsulates remains in stone-like cocoon PETRIFICATION - Minerals will infiltrate structure and replace the organic material cell by cell EXPOSURE - “Discovery” stage - weathering or erosion may bring the fossil back to the surface 32. What is speciation and how is it represented in the fossil record. Speciation is the evolutionary process where a new species arises from an existing one, typically occurring when a population becomes geographically isolated and develops distinct characteristics eventually leading to reproductive isolation from the original population; in the fossil record, speciation is observed as a branching pattern where a lineage splits into two or more distinct forms over time, often showing transitional fossils that document the gradual morphological changes between the ancestral species and the newly formed species, Biozones and Faunal Succession (ES.7.E) 33. Biozones are defined by: ○ a) The presence of specific rock types. ○ b) The presence of specific fossils. ○ c) The thickness of rock layers. ○ d) The age of the rocks. 34. Faunal succession is the principle that: ○ a) Fossil organisms succeed one another in a definite and determinable order. ○ b) All fossils are found in the same rock layers. ○ c) Older fossils are always found deeper in the Earth's crust. ○ d) Fossil organisms evolve at a constant rate. 35. How can biozones be used to correlate rock layers from different locations? ○ a) By comparing the thickness of the rock layers. ○ b) By analyzing the mineral composition of the rocks. ○ c) By identifying the same fossil assemblages in different locations. ○ d) By measuring the age of the rocks using radiometric dating. 36. What can biozones tell us about past environments? ○ a) The climate of the region ○ b) The type of organisms that lived there ○ c) The depth of the water ○ d) All of the above 37. Define biozones and discuss how they reveal information about past environments. Biozones are zones of well-documented fossil species with distinct origination and extinction times. Specific biozones can be defined a number of ways: The total time of a fossil's existence. It could consist of the total time where two or more fossils coexist. It could be defined as the time between the origination of one fossil and the extinction of a different fossil, etc 38. What do biozones tell us about the dynamic nature of Earth? That life evolves through time. Biozones show us how Earth has always been changing and will continue to change and evolve over time. 39. Provide an example of faunal succession in rock layers and explain its significance. A classic example of faunal succession is finding dinosaur fossils in a lower rock layer, followed by mammal fossils in a higher layer, indicating that dinosaurs lived before mammals, allowing geologists to relatively date rock strata based on the fossil assemblages present within them; this principle is crucial for understanding the evolutionary timeline and correlating rock formations across different geographical locations.