1. FOSSILS
UNIT ONE

2. How do most fossils form?
WARM-UP #1
How do most fossils form?

3. Living things die and their remains are covered by sediments.
ANSWER
Living things die and their remains are covered by sediments.

4. WARM-UP #2
A fossil formed when minerals replace all or part of an organism is called____________.

5. ANSWER
Petrified fossil

6. WARM-UP #3
Which type of fossil can provide clues about the activities of ancient organisms?

7. ANSWER
Trace fossil

8. VOCABUALRY
Fossil
Mold & cast
Petrified

9. VOCABULARY
Fossil
A trace of an ancient organism that has been preserved in rock
Mold & cast
A fossil formed when an organism buried in sediment dissolves, leaving a hollow area

10. A fossil in which minerals replace all or part of an organism
VOCABULARY
Petrified
A fossil in which minerals replace all or part of an organism

11. WARM-UP #4
The fossil record shows that life on Earth has changed over time. For example, paleontologists have found that older rocks contain fossils of

12. organisms that are simpler than those alive today.
ANSWER
organisms that are simpler than those alive today.

13. The relative age of a rock is
WARM-UP #5
The relative age of a rock is

14. its age compared to the ages of other rocks.
ANSWER
its age compared to the ages of other rocks.

15. WARM-UP #6
The law of superposition states that, in horizontal layers of sedimentary rock, each layer is

16. older than the layer above it and younger than the layer below it.
ANSWER
older than the layer above it and younger than the layer below it.

17. VOCABUALRY
Carbon film
Trace
Paleontologist

18. VOCABUALRY Carbon film
A type of fossil consisting of an extremely thin coating of carbon on rock
Trace
A type of fossil that provides evidence 0f the activities of the ancient organism

19. VOCABUALRY
Paleontologist
A scientist that studies fossils to learn about organisms that lived a long time ago

20. WARM-UP #7
What is the age of an intrusion of igneous rock in relation to the sedimentary rock layers through which it passes?

21. ANSWER
always younger

22. WARM-UP #8
The fossils of organisms that were widely distributed but only lived during a short period of time are called

23. ANSWER
index fossils.

24. Why are index fossils useful to geologists?
WARM-UP #9
Why are index fossils useful to geologists?

25. They tell the relative age of the rock in which they occur.
ANSWER
They tell the relative age of the rock in which they occur.

26. VOCABUALRY
Relative age
Absolute age
Law of superposition

27. VOCABUALRY Relative age
The age of a rock compared to the ages of rock layers
Absolute age
The age of a rock given as the number of years since the rock formed

28. VOCABULARY
Law of superposition
The geologic principle that states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it

29. The earliest life forms were
WARM-UP #10
The earliest life forms were

30. single-celled organisms.
ANSWER
single-celled organisms.

31. WARM-UP #11
What is a fossil?

32. the preserved remains or traces of an organism
ANSWER
the preserved remains or traces of an organism

33. WARM-UP #12
In which type of fossil might you find the remains of an insect preserved with little or no change?

34. ANSWER
fossil in amber

35. VOCABUALRY
unconformity
Index fossil

36. VOCABUALRY Unconformity
A place where old, eroded rock surface is in contact with a newer rock layer
Index fossil
Fossils distributed organisms that lived during only one short period

37. WARM-UP #13
A type of organism that no longer exists on Earth is said to be __________.

38. ANSWER
extinct.

39. Fossils usually occur in _____________________ rock.
WARM-UP #14
Fossils usually occur in _____________________ rock.

40. ANSWER
sedimentary

41. Generally, only the ________ parts of organisms become fossils.
WARM-UP #15
Generally, only the ________ parts of organisms become fossils.

42. ANSWER
hard

43. VOCABUALRY
Hydrocarbon
Petroleum

44. VOCABUALRY
Hydrocarbon
An energy-rich chemical compound that contains carbon and hydrogen atoms
petroleum
Liquid fossil fuel; oil

45. Footprints and trails are examples of__________________.
WARM-UP #16
Footprints and trails are examples of__________________.

46. ANSWER
Trace fossils

47. WARM-UP #17
The law of superposition helps geologists determine the________________ age of a rock layer.

48. ANSWER
relative

49. WARM-UP #18
Rock layers are always _______________ than the faults that cut across them.

50. ANSWER
older

51. VOCABUALRY