When comparing geologic time to a calendar year, the time of the dinosaurs is in the

1. When comparing geologic time to a calendar year, the time of the dinosaurs is in the • middle of October. • first half of December. • second half of December. • first half of February.

2. When comparing geologic time to a calendar year, the time of the dinosaurs is in the • middle of October. • first half of December. • second half of December. • first half of February. Explanation: Amazing as it may seem to many people, dinosaurs are a recent phenomenon in Earth’s long history.

3. The present is the key to the past is a fundamental part of • catastrophism. • plutonism. • neptunism. • uniformitarianism.

4. The present is the key to the past is a fundamental part of • catastrophism. • plutonism. • neptunism. • uniformitarianism. Explanation: Uniformitarianism holds that the physical, chemical, and biological principles that operate today also operated in the past. Thus, the present is the key to the past.

5. Which of the following is NOT a principle of relative dating? • Original horizontality. • Faunal superposition. • Cross-cutting. • Inclusion.

6. Which of the following is NOT a principle of relative dating? • Original horizontality. • Faunal superposition. • Cross-cutting. • Inclusion. Explanation: Faunal succession and superposition are the other two principles.

7. What is the principle of superposition? • Each sedimentary layer is older than the layer above. • Each sedimentary layer is younger than the layer above. • Each new layer of sediment is laid down nearly horizontally. • Each new layer of sediment is laid down accordingly.

8. What is the principle of superposition? • Each sedimentary layer is older than the layer above. • Each sedimentary layer is younger than the layer above. • Each new layer of sediment is laid down nearly horizontally. • Each new layer of sediment is laid down accordingly. Explanation: Superposition relates to age of sediments. It is impossible for a layer of sediment to get deposited underneath a layer that was already in place.

9. What is the principle of original horizontality? • Each sedimentary layer is older than the layer above. • Each sedimentary layer is younger than the layer above. • Each new layer of sediment is laid down nearly horizontally. • Each new layer of sediment is laid down accordingly.

10. What is the principle of original horizontality? • Each sedimentary layer is older than the layer above. • Each sedimentary layer is younger than the layer above. • Each new layer of sediment is laid down nearly horizontally. • Each new layer of sediment is laid down accordingly.

11. In a thick bed of sedimentary rocks, we find an igneous dike. The order in which the rocks formed is • simultaneously. • igneous before sedimentary. • sedimentary before igneous. • unknown.

12. In a thick bed of sedimentary rocks, we find an igneous dike. The order in which the rocks formed is • simultaneously. • igneous before sedimentary. • sedimentary before igneous. • unknown.

13. The principle that different forms of animals throughout Earth’s past occurred in a definite order is called the principle of • fossil assemblage. • faunal succession. • conformable fossils. • fossil determination.

14. The principle that different forms of animals throughout Earth’s past occurred in a definite order is called the principle of • fossil assemblage. • faunal succession. • conformable fossils. • fossil determination.

15. What is an unconformity? • A scientific debate between Earth scientists. • Younger igneous plutonic rock above older sediments. • A continuous sequence of sedimentary layers. • A gap in an otherwise continuous time-sequence of rock layers.

16. What is an unconformity? • A scientific debate between Earth scientists. • Younger igneous plutonic rock above older sediments. • A continuous sequence of sedimentary layers. • A gap in an otherwise continuous time-sequence of rock layers. Explanation: Unconformities represent a missing record of time, like pages missing from a book.

17. The time it takes for 50% of a radioactive substance to decay is known as • radiometric dating. • carbon-14. • the proportion of atoms remaining. • the half-life.

18. The time it takes for 50% of a radioactive substance to decay is known as • radiometric dating. • carbon-14. • the proportion of atoms remaining. • the half-life.

19. By radiometric dating, the oldest mineral in a sedimentary rock was found to be 1.4 million years old. What is the age of the sedimentary rock? • Radiometric dating does not work for sedimentary rocks. • 1.4 million years. • No older than 1.4 million years. • No younger than 1.4 million years.

20. By radiometric dating, the oldest mineral in a sedimentary rock was found to be 1.4 million years old. What is the age of the sedimentary rock? • Radiometric dating does not work for sedimentary rocks. • 1.4 million years. • No older than 1.4 million years. • No younger than 1.4 million years. Explanation: The principle of inclusions tells us that the sedimentary rock cannot be older than the minerals of which it is composed.

21. The numerical dates associated with events on the geologic time scale were determined by • radiometric dating. • relative dating. • superposition. • fossil assemblages through time.

22. The numerical dates associated with events on the geologic time scale were determined by • radiometric dating. • relative dating. • superposition. • fossil assemblages through time. Explanation: Presently, the only way to obtain numerical dates is with radiometric dating.

23. Life forms in the Precambrian include • trilobites. • brachiopods. • coelacanths. • cyanobacteria.

24. Life forms in the Precambrian include • trilobites. • brachiopods. • coelacanths. • cyanobacteria.

25. Development of Earth’s oceans was likely due to • water-rich meteors bombarding Earth’s surface. • volcanic outgassing in Precambrian time. • slow convection in the mantle. • volcanic outgassing in the early Paleozoic.

26. Development of Earth’s oceans was likely due to • water-rich meteors bombarding Earth’s surface. • volcanic outgassing in Precambrian time. • slow convection in the mantle. • volcanic outgassing in the early Paleozoic. Explanation: Comets are thought to contribute some water to the oceans, but the majority of water on Earth is from outgassing that occurred very early in Earth’s history.

27. The most important event during the Cambrian period was the • emergence of the fishes. • ability of organisms to form an outer skeleton. • emergence of the trilobite. • ability of organisms to develop lungs.

28. The most important event during the Cambrian period was the • emergence of the fishes. • ability of organisms to form an outer skeleton. • emergence of the trilobite. • ability of organisms to develop lungs. Explanation: The evolutionary development of an outer skeleton increased survival rates.

29. Ancient geologic processes as revealed in Paleozoic rock layers were • predominantly volcanic in origin. • primarily glacial. • predominantly processes of erosion and sedimentation. • very similar to processes seen today.

30. Ancient geologic processes as revealed in Paleozoic rock layers were • predominantly volcanic in origin. • primarily glacial. • predominantly processes of erosion and sedimentation. • very similar to processes seen today. Explanation: Remember: The present is the key to the past!

31. Which of the following is NOT true of the fossil record? • The fossil record spans about 3.5 billion years of Earth’s 4.5 billion year age. • The most common fossils are those organisms that had hard parts like shells and bones. • The first fossils were simple, anaerobic algal plants. • The Paleozoic era is credited with the emergence of life.

32. Which of the following is NOT true of the fossil record? • The fossil record spans about 3.5 billion years of Earth's 4.5 billion year age. • The most common fossils are those organisms that had hard parts like shells and bones. • The first fossils were simple, anaerobic algal plants. • The Paleozoic era is credited with the emergence of life. Explanation: Life emerged in Precambrian time, which precedes the Paleozoic era.

33. Coal is composed of • petrified wood. • buried plant material that has partially decayed. • buried animal material that has partially decayed. • a combination of oil-rich sediments and calcareous ooze.

34. Coal is composed of • petrified wood. • buried plant material that has partially decayed. • buried animal material that has partially decayed. • a combination of oil-rich sediments and calcareous ooze.

35. Most coal deposits were formed in the • Cenozoic era. • Mesozoic era. • Paleozoic era. • Precambrian time.

36. Most coal deposits were formed in the • Cenozoic era. • Mesozoic era. • Paleozoic era. • Precambrian time. Explanation: Specifically, most coal deposits formed in the Carboniferous period, which is in the Paleozoic era.

37. The formation of the supercontinent of Pangaea • resulted from the collision of all major landmasses. • produced widespread mountain building in the Himalayas. • resulted in extensive volcanic activity and flood basalts. • resulted from all of these.

38. The formation of the supercontinent of Pangaea • resulted from the collision of all major landmasses. • produced widespread mountain building in the Himalayas. • resulted in extensive volcanic activity and flood basalts. • resulted from all of theses. Explanation: There was extensive mountain building, for example in the Appalachians, but the Himalayas are a recent occurrence.

39. The Mesozoic era is known as the age of the • dinosaurs. • synapsids. • fishes. • reptiles.

40. The Mesozoic era is known as the age of the • dinosaurs. • synapsids. • fishes. • reptiles. Explanation: Dinosaurs are but one group of reptiles.

41. What is an explanation for the discovery of ancient coal beds in Antarctica? • Antarctica’s climate was once mild enough to support swamplands. • The ancient coal beds were frozen in the Antarctic ice. • Antarctica was at one time located in the Northern Hemisphere. • Massive upheavals occurred during the Mesozoic era.

42. What is an explanation for the discovery of ancient coal beds in Antarctica? • Antarctica’s climate was once mild enough to support swamplands. • The ancient coal beds were frozen in the Antarctic ice. • Antarctica was at one time located in the Northern Hemisphere. • Massive upheavals occurred during the Mesozoic era. Explanation: Climate has been quite variable over geologic time.

43. The birth of the San Andreas Fault corresponds to • the collision of the Pacific Plate and the Hawaiian islands. • the collision of the Pacific ridge system and North America. • the movement of the Pacific Plate over a turbulent zone. • the collision of India and Eurasia.

44. The birth of the San Andreas Fault corresponds to • the collision of the Pacific Plate and the Hawaiian islands. • the collision of the Pacific ridge system and North America. • the movement of the Pacific Plate over a turbulent zone. • the collision of India and Eurasia.