2. Uniformitarianism: the processes that act on the Earth’s surface today are the same as the processes that have acted on the Earth’s surface in the past James Hutton “The present is the key to the past”

3. age of anything compared to the age of something else doesn’t indicate actual date of occurrence

4. law of superposition: in undisturbed rock, the older rocks will be at the bottom and the youngest rocks will be at the top

7. law of cross-cutting relationships:an igneous rock cutting through another rock is younger than the rock it has cut-cross

11. law of included fragments: pieces of one rock found in another rock must be older than the rock in which they are found

14. Contorted rock, hard to determine relative age (Copiapo, Chile) unconformity: break in the geologic rock record

15. nonconformity: when stratified rock rests upon unstratified rock

16. Noncomformity 1.Granite formed 2. Granite exposed by erosion 3. Beds 1-3 deposited

17. angular unconformity: boundary between horizontal and tilted layers of rock

18. Angular Unconformity 1.Beds 1-6 deposited 2. Beds 1-6 tilted 3. Erosion 4. Beds 9,10 deposited

20. disconformity:boundary between layers of rock that have not been deposited continuously

21. Disconformity 1.Beds 1,2 deposited 2. Erosion 3. Beds 5, 6, 7 deposited

23. absolute age: identifies actual age of a rock layer if actual time of two events is known, the length of time between two events can be calculated

24. fossil: remains or evidence of living things

25. (1) original remains: the actual, unchanged remains of the organism are preserved

26. (a) frozen in ice

27. (b) preserved in amber(tree sap that has hardened

28. (c) mummification

29. (2) replaced remains: soft parts of the organism have disappeared and been replaced by minerals

30. petrification

31. (3) molds and casts of the original organism (4) trace fossils: evidence of life other than remains of an organisms activities and/or appearance

32. (a) footprints (b) imprint (c) tracks, trails, burrows, borings

33. coprolites: fossilized dung or waste materials from ancient animals T-Rex Carnivore Coprolite (8 lbs.)

34. gastroliths: fossilized stone found within the digestive system of a dinosaur or other reptile

36. index fossil: fossils found exclusively in rock record of a particular geologic age must have (4) characteristics: (1) must be easily recognizable (2) must be widespread in occurrence (3) must be limited in time (4) must be found in large numbers with the rock layer

38. geologic time scale: summary of major events of the Earth’s history preserved in the rock record the history of the Earth is divided by major changes in the Earth’s surface, climate and/or species

40. Eras: largest segment of time (1) Precambrian (2) Paleozoic- “ancient life” (3) Mesozoic- “middle life” (4) Cenozoic- “recent life” Eras are divided into Periods, Periods are divided into Epochs

41. theory of evolution: theory that organisms change over time and new organisms are derived from ancestral types theory proposed by Charles Darwin