7th Grade - Chapter 9 ONLINE REVIEW

7th Grade - Chapter 9 ONLINE REVIEW
True/False
Indicate whether the statement is true or false.
____ 1. Fossils most often form when a dead organism is buried in sediments.
____ 2. Carbon films are formed when a thin film of carbon is left, forming a silhouette of the original organism.
____ 3. Dinosaur footprints are original remains.
____ 4. To be a useful index fossil, a species must have been rare.
____ 5. Nonconformities occur when sedimentary rocks are deposited on top of uplifted and eroded metamorphic or igneous rocks.
____ 6. Radiocarbon dating would be useful in dating the age of Earth.
____ 7. Index fossils are the remains of species that existed on Earth for relatively short periods of time.
____ 8. Absolute age examines the position of rocks in a sequence.
____ 9. A fossil may tell a geologist when, where, and how an organism lived.
____ 10. An era is the longest subdivision of geologic time.
____ 11. The soft parts of organisms are most likely to become fossils.
____ 12. Trilobites are used as index fossils.
____ 13. Only a radioactive isotope will have a half-life.
____ 14. Any fossil can be dated by the amount of carbon-14 it contains.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 15. A paleontologist finds the original remains of an organism. Which of the following are original remains?
a.
the cast or mold of a seashell
b.
trails and burrows in sediment
c.
tracks in mud that harden into rock
d.
an insect preserved in amber
____ 16. A scientist finds a crinoid fossil in a desert. What can the scientist conclude from this find?
a.
The desert used to have tropical plants.
b.
The area was once covered by a shallow sea.
c.
The desert was once icy and wintry.
d.
The area had very few organisms living there in the past.
____ 17. Trilobites developed different characteristics over geologic time. What can geologists learn from these changes?
a.
why the climate changed many times over the eons
b.
how trilobites responded to changes in their environments
c.
where different types of trilobites lived in ancient times
d.
what kinds of organisms lived when trilobites lived
____ 18. Denise is writing a report about unconformities. How do unconformities develop?
a.
Animals die and are covered by sediment.
b.
Glaciers scrape away rock layers.
c.
The climate in the area changes dramatically.
d.
Mineral deposits turn sediment into rock.
____ 19. Which of the following organisms has the best chance of becoming a fossil?
a.
a very small organism
b.
an organism with hard parts
c.
a very large organism
d.
an aquatic organism
____ 20. Deon wants to study a more recent geologic time period.

Which of the following should he read about?
a.
Eocene
b.
Holocene
c.
Pliocene
d.
Tertiary
____ 21. How do angular unconformities develop?
a.
Layers of sedimentary rock are tilted and uplifted.
b.
Metamorphic or igneous rock is uplifted and eroded.
c.
Winds blow away layers of sedimentary or igneous rock.
d.
Young rocks form on the eroded surface of old rocks.
____ 22. Garret finds a silhouette of an organism on a rock. Which type of fossil did Garret find?
a.
carbon film
b.
cast
c.
mineral replacement
d.
mold
____ 23. Ramona reads that organisms become more complex over the course of geologic time.

Based on this information, which eon took place most recently?
a.
Archean
b.
Phanerozoic
c.
pre-Archean
d.
Proterozoic
____ 24. Which subdivision of geologic time spans the greatest number of years?
a.
eon
b.
epoch
c.
era
d.
period
____ 25. A paleontologist looks at a fossil to study the eyes of a trilobite. The trilobite has eyes toward the front of its head. What can the paleontologist conclude from this fact?
a.
The trilobite crawled along the sea floor.
b.
The trilobite lived underground.
c.
The trilobite swam in the water.
d.
The trilobite burrowed into the sediment.
____ 26. A geologist determines the relative age of a section of rock. What does the relative age tell the scientist?
a.
how many millions of years old the rock is
b.
what organisms lived in or near the rock
c.
how old the rock is compared to nearby rocks
d.
what unconformities developed in the rock
____ 27. A hiker in the desert finds a set of dinosaur tracks. What type of fossil did the hiker find?
a.
carbon film
b.
mineral replacement
c.
original remains
d.
trace fossils
____ 28. All of the following conditions help preserve organisms as fossils EXCEPT ____.
a.
quick burial by sediments
c.
protection from scavengers
b.
hard parts
d.
activities of microorganisms
____ 29. If the same types of fossils are found in two separate rock layers, it's likely that the two rock layers ____.
a.
formed at different times
c.
formed under different conditions
b.
are part of one continuous deposit
d.
none of the above
____ 30. Determining the order of events and the relative age of rocks by examining the position of rocks in a sequence is called ____.
a.
absolute dating
c.
relative dating
b.
radiometric dating
d.
radiocarbon dating
____ 31. Gaps in rock layers are called ____.
a.
unconformities
c.
half-lives
b.
index fossils
d.
none of the above
____ 32. If the same sequence of rock layers is observed over a large area, ____.
a.
they are probably not related
b.
a large deposit of rock formed over a large area
c.
conditions of formation were probably very different
d.
it is just a coincidence
____ 33. A limestone bed containing fossils that are 550 million years old is ____ a bed of sandstone containing fossils that are 400 million years old.
a.
younger than
c.
older than
b.
the same age as
d.
not related to
____ 34. In a series of undisturbed rock layers where shale lies between sandstone below and limestone above, the ____.
a.
limestone is youngest
c.
sandstone is youngest
b.
shale is youngest
d.
beds are all the same age
____ 35. ____ dating uses the properties of atoms in rocks and other objects to find their ages.
a.
Comparative
c.
Approximate
b.
Absolute
d.
Relative
____ 36. Rock layers are correlated if they both contain the same ____.
a.
elements
c.
fossils
b.
shapes
d.
type of rock
____ 37. If a layer of sandstone lies on top of a layer of limestone in which a 300-million-year-old fossil is found, and there are no unconformities, the layer of sandstone must be ____.
a.
older than 300 million years
c.
about 300 million years old
b.
younger than 300 million years
d.
older than 600 million years
____ 38. With ____ dating, a rock's exact age can be determined, whereas with ____ dating, a rock's age is compared to the ages of other rocks.
a.
absolute, relative
c.
true, absolute
b.
relative, absolute
d.
relative, approximate
Matching
Match each item with the correct statement below.
a.
remains
e.
missing layer
b.
fossil
f.
trace
c.
mold
g.
radioactive decay
d.
hard
h.
carbon-14
____ 39. A ______ may tell a geologist when, where, and how an organism lived.
____ 40. A ______ is the cavity left behind in the rock after an organism's hard part has dissolved.
____ 41. Fossils up to 75,000 years old can be dated with ______.
____ 42. The ______ parts of organisms are most likely to become fossils.
____ 43. Fossils are the ______, imprints, or traces of once-living organisms preserved in rock.
____ 44. An unconformity is a ______ of rock.
____ 45. Preserved animal tracks are called ______ fossils.
____ 46. is measured in half-lives
Match each item with the correct statement below.
a.
carbonaceous film
g.
index fossils
b.
cast
h.
mold
c.
principle of superposition
i.
uniformitarianism
d.
radiometric dating
j.
radioactive decay
e.
beta decay
k.
relative dating
f.
half-life
l.
unconformities
____ 47. the process in which one of an isotope's neutrons breaks down into a proton and an electron and the electron leaves the atom as a beta particle [beta decay]
____ 48. fossil formed when an outline of the original organism is formed from left-over carbon
____ 49. made when sediments fill in a cavity made when an object decayed and the sediments harden into rock
____ 50. the time it takes for half of the atoms in an isotope to decay
____ 51. fossils of species that lived on Earth for short periods of time and were abundant and were widespread geographically
____ 52. states that for undisturbed rocks, the oldest rocks are on the bottom and the rocks become younger and younger toward the top
____ 53. hollow place in rock made when an organism died and was buried and holes in the rock let air or water reach it and dissolve the organism
____ 54. the process of calculating the absolute age of a rock by measuring the amounts of parent and daughter materials in a rock and by knowing the half-life of the parent
____ 55. a process that uses the properties of atoms in rocks and other objects to find their ages
____ 56. the order of events and the relative age of rocks is determined by examining the position of rocks in a sequence
____ 57. gaps in rock layers that develop when agents of erosion remove existing rock layers
____ 58. states that Earth processes today are similar to those that took place in the past
Match each term with the correct description below.
a.
cast
h.
mold
b.
carbonaceous film
i.
radioactive decay
c.
index fossils
j.
relative dating
d.
fossil
k.
unconformities
e.
half-life
l.
radiometric dating
f.
principle of superposition
m.
uniformitarianism
g.
absolute dating
n.
permineralized remains
____ 59. produced when sediments fill in a cavity made when an object decayed
____ 60. cavity in rock made when an organism decayed
____ 61. principle that Earth's processes occurring today are similar to those that occurred in the past
____ 62. process that uses the properties of atoms in rocks and other objects to determine their ages
____ 63. states that in a sequence of undisturbed rocks, the oldest rocks are on the bottom and the rocks become progressively younger toward the top
____ 64. gaps in rock records made when agents of erosion remove existing rock layers
____ 65. method by which a geologist can calculate the absolute age of the rock by knowing the half-life of an isotope
____ 66. time it takes for half of an isotope's atoms to decay
____ 67. three-lobed organism that inhabited Earth's oceans for more than 200 million years
____ 68. formed when original materials in skeletal remains are replaced by minerals
____ 69. the division of Earth's history based on types of life-forms living during certain periods
____ 70. remains, imprints, or traces of once-living organisms
____ 71. process that occurs when the number of protons in an atom is changed and a new element is formed
____ 72. fossils of species that existed for short periods and were widespread
Short Answer
73.
A paleontologist wants to search for fossils in the oldest rocks of a canyon. Describe where the paleontologist would most likely find the oldest rocks.
74.
Carla is learning about index fossils. How are index fossils helpful to geologists?

Figure 13-1
75.
List events A-F shown in Figure 13-1 in the order that they occurred, beginning with the oldest event.
76.
When did the fault in Figure 13-1 occur?
77.
If horizontal layers of sedimentary rock have a vertical fault running through them, how might a geologist use relative dating to determine when the fault occurred?
78.
Do all rocks contain fossils? Describe the conditions necessary for fossils to form.
79.
Explain what is meant by correlating rock layers.
80.
Explain what the term half-life means and how knowing the half-life of an element can help a geologist establish the age of a rock or fossil.
81. Complete the chart to describe different types of fossils.
Type of fossil
Description
1. Permineralized remains

2. Carbon film

3. Mold

4. Cast

5. Trace fossils

6. Index fossils

82. Explain what the concept of uniformitarianism means.
83. What units divide the geologic time scale?
84. Explain how a dead organism may become a fossil.
85. Complete the concept map below by writing the conditions for fossil formation and the types of fossils in the circles.

86. What is the difference between relative and absolute dating?
Study the figure of the rock record. Then answer the following questions.

87. List events A-F in the order they occurred, beginning with the oldest event.
88. When did the fault occur?
89. Complete the table below to show the amounts of parent and daughter materials left of a radioactive element after three half-lives if the original parent had a mass of 80 g.
Number of half-lives
Parent material
Daughter product
1.


2.


3.


Problem
90.
A sample of a radioactive element has a mass of 80 g. How much parent and daughter materials are in the sample after two half-lives?

Figure 13-2
91.
According to Figure 13-2, if 25 percent of the parent material remains in a rock sample, how many half-lives have occurred?
92.
Refer to Figure 13-2 and determine how much parent material will be left after five half-lives.
Essay
93. If horizontal layers of sedimentary rock have a vertical fault running through them, how might a geologist use relative dating to determine when the fault occurred?
94. Explain how a trace fossil can provide information on how an organism lived.
95. Explain what is meant by correlating rock layers.
96. Do all rocks contain fossils? Describe the conditions necessary for fossils to form.
97. Explain what the term half-life means and how knowing the half-life of an isotope can help a geologist establish the age of a rock or fossil.