Directed Reading. Section: The Fossil Record. Skills Worksheet

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1 Skills Worksheet Directed Reading Section: The Fossil Record 1. For what geological information are fossils an important source? a. learning whether rock is sedimentary, igneous, or metamorphic b. finding the absolute and relative ages of rocks c. seeing the erosion patterns on ancient rocks d. learning whether rocks have intrusions or faults 2. Fossils provide clues to a. past geologic events, climates, and evolution of living things. b. past weather, cloud cover, and changes in seasons. c. recent events in human history. d. the earliest development of the Solar System. In the space provided, write the letter of the description that best matches the term or phrase. 3. fossil 4. paleontology 5. sedimentary rock 6. igneous or metamorphic rock a. the type of rock in which almost all fossils are discovered b. the study of fossils c. the remains of an animal or plant that lived in a previous geologic time d. rock in which fossils are rarely discovered 7. Why are most fossils found in sedimentary rock? 8. Why are fossils so rarely found in igneous or metamorphic rock? Holt Earth Science 22 The Rock Record

2 IN TE RP RE TIN G TH E FO SSIL RE C O RD 9. What type of information does the fossil record provide? 10. How do fossils provide important clues to environmental changes that occurred in E arth s past? 11. What is one way scientists can tell if an area of land was once covered by an ocean? 12. What is one way scientists can use information from fossils? FO SSIL IZ A TIO N 13. What usually happens to dead plants or animals? a. T hey become fossils. b. T hey just stay where they are. c. T hey are eaten or decomposed by bacteria. d. Nothing happens to them. 14. Which type of organisms usually become fossils? a. organisms that were buried q uickly or protected from decay b. organisms that were ignored by passing animals. c. organisms that lived in water. d. organisms that had hard outer shells. 15. In general, what parts of organisms become fossils? a. all parts are eq ually likely to be fossiliz ed b. hard parts, such as wood, bones, shells, or teeth c. soft parts, such as skin and organs d. only very hard woods Holt Earth Science 23 The Rock Record

3 16. Why are mummified remains found in very dry places? a. M ost bacteria thrive in dry environments. b. B acteria do not cause decay in dry environments. c. Fewer animals live in dry environments. d. M ost bacteria cannot survive in dry environments. 17. Which method of fossiliz ation was also used by ancient civiliz ations? a. petrification b. ex cretion c. mummification d. deposition 18. How are insects preserved in amber? a. T hey eat tree sap, which preserves their bodies. b. T hey become trapped in tree sap, which hardens. c. T hey lay eggs in sap, which hatch before the sap hardens. d. T ree sap is very dry, and few bacteria live in it. 19. What material has been recovered from amber in rare cases? a. DNA b. RNA c. living insects d. antennae 20. T ar seeps are formed by thick deposits of a. clay. b. amber. c. petroleum. d. silica 21. What about tar seeps led fossiliz ed animals to become trapped in the sticky tar? a. T ar smells good to animals. b. T ar seeps are commonly covered by water. c. T ar seeps are often found in steep holes. d. T ar seeps are surrounded by food. 22. Which is a common petrifying mineral? a. talc b. molybdenum c. silica d. gypsum Holt Earth Science 24 The Rock Record

4 TY P E S O F FO SSIL S 23. An imprint displays a. an ex act, complete form of an organism. b. internal details of an organism. c. the hard portions of an organism. d. the surface features of an organism. 24. Which type of fossil is formed when mud fills a mold and hardens? a. an imprint b. a mold c. a cast d. a coprolite 25. What does a cast show about an animal? a. It shows how an animal reproduced. b. It provides an ex act replica of the animal. c. It shows what the animal s natural enemies were. d. It provides a general idea of the animal s siz e. 26. What type of fossil gives scientists clues about what ancient animals ate? a. an imprint b. a cast c. a coprolite d. a mold 27. G astroliths are commonly found a. in layers of clay. b. close to dinosaur remains. c. at the bottoms of tar seeps. d. in empty pockets within shale. 28. A trace fossil is a. fossiliz ed dung or waste materials from ancient animals, such as dinosaurs. b. fossiliz ed evidence of past animal movement such as a track, footprint, boring, or burrow. c. the carboniz ed outline of a leaf, stem, flower, or fish that was made in soft mud or clay. d. the complete fossiliz ed body of an ancient animal. 29. Scientists study trace fossils to find a. ex actly what an animal looked like. b. precisely what an animal weighed. c. clues to an animal s appearance and activities. d. clues to what an animal ate. Holt Earth Science 25 The Rock Record

5 30. Which of the following is an ex ample of a trace fossil? a. an intact dinosaur tooth b. a bird s footprint c. an imprint of a leaf d. a spider in amber 31. From what kinds of animals have scientists found trace fossils of footprints? IN D E X FO SSIL S 32. Fossils that are found only in the rock layers of a particular geologic period are called a. trace fossils. b. imprints. c. index fossils. d. complete fossils. 33. Index fossils are found a. in a very small geographic area. b. in igneous rocks. c. widely scattered in rocks over a large region. d. widely scattered through many layers of rocks. 34. What is most important about the features of an index fossil? a. Its features must be recogniz ed as coming from other organisms that became fossils. b. Its features must be eq ually clear in each of the different fossils found. c. Its features must differ according to the location on E arth in which it is found. d. Its features must clearly distinguish it from other fossils. 35. T he organisms that form index fossils lived a. during a short span of geologic time. b. during a long span of geologic time. c. for about 2 million years d. over any span of geologic time, long or short. Holt Earth Science 26 The Rock Record

6 36. How commonly distributed must the fossil of an organism be in order to be considered an index fossil? a. T he fossil must be rare and uniq ue. b. T he fossil must occur in fairly large numbers within the rock layers. c. T he fossil may ex ist in any numbers, but it must be found within many different layers of rock. d. T he fossil must occur in small numbers in a very specific location. IN D E X FO SSIL S A N D A B SO L U TE A G E 37. Scientists use index fossils to a. determine the relative ages of different rock layers. b. find dividing points in the fossil record. c. determine branches in the development of species. d. determine the absolute ages of specific rock layers. 38. Rock layers in which index fossils have been found can be dated accurately because the organisms that formed the index fossils lived a. for a long span of geologic time. b. for a short span of geologic time. c. all over E arth. d. in a small part of E arth. 39. How old are the rock layers in which ammonite fossils are found? a and million years b to million years c to million years d to million years 40. How can scientists use index fossils to determine the absolute age of rock layers in different parts of the world? 41. What else do geologists use index fossils to find? Holt Earth Science 27 The Rock Record