6th Grade - Chapter 11 Online Review

6th Grade - Chapter 11 Online Review
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 1. Which describes the surface processes that break down rock?
a.
breakdown
b.
climate
c.
gravity
d.
weathering
____ 2. What two types of weathering shape Earth's surface?
a.
ice wedging and sand
b.
magnetite and climate
c.
mechanical and chemical
d.
oxidation and silt
____ 3. Bill is creating a poster about soil formation.

What other factor affects soil formation?
a.
carbon dioxide
b.
fertilizer
c.
gravity
d.
type of vegetation
____ 4. Suzanne needs good soil for her new garden. Equal amounts of what two materials make up the good-quality soil she needs?
a.
granite and weathered silt material
b.
humus and weathered rock material
c.
nodules of hard rock and clay
d.
weathered sand material and clay
____ 5. What occurs when rocks are broken apart by physical processes?
a.
chemical weathering
b.
fragment weathering
c.
mechanical weathering
d.
radiant weathering
____ 6. At a plant nursery, Lori learned that her favorite flower grows best in soil with a pH balance of 7. What kind of pH balance does this soil have?
a.
equal
b.
negative
c.
neutral
d.
positive
____ 7. While on a vacation, Miguel notices some rocks that have a reddish color. What might explain the color of the rocks?
a.
acidic soil
b.
climate
c.
mechanical weathering
d.
oxidation
____ 8. Sean is looking at a place where a nearby highway cuts through some hills. He is particularly curious about the level of soil that seems to consist of partially weathered rock. What horizon is Sean looking at?
a.
A horizon
b.
B horizon
c.
C horizon
d.
D horizon
____ 9. Which type of soil structure has small peds due to mixing by earthworms, frost, and rodents?
a.
blocky
b.
granular
c.
platy
d.
prismatic
____ 10. Kathy's class has been learning about soil. Kathy has almost completed a sheet about topsoil.

What is another characteristic of topsoil?
a.
consists almost entirely of sand
b.
holds water well
c.
lasts longer if overgrazed
d.
quickly erodes if no-till farming is used
____ 11. Why is soil on steep slopes often poorly developed?
a.
Almost all the good material stays near the top of the slope.
b.
Material moves downhill before it can be weathered.
c.
Poor material tends to stay near the bottom of steep slopes.
d.
Water tend to move toward the bottom of steep slopes.
____ 12. Why can overgrazing damage soil?
a.
Animals' feet damage the soil.
b.
It increases moisture in the soil.
c.
Soil is carried away by wind.
d.
Trees cannot grow where animals graze.
____ 13. Soil is a mixture of weathered rock, mineral fragments, water, air and ____.
a.
sand
c.
moss
b.
decayed organic matter
d.
clay
____ 14. The layer of soil that contains the most organic material is called the ____ horizon.
a.
A
c.
C
b.
B
d.
D
____ 15. All of the following cause mechanical weathering EXCEPT ____.
a.
ice
c.
burrowing animals
b.
tree roots
d.
carbonic acid
____ 16. Litter often covers the ____ horizon.
a.
A
c.
C
b.
B
d.
all of the above
____ 17. Chemical weathering is more rapid in a ____ climate.
a.
warm, dry
c.
cold, dry
b.
warm, wet
d.
cold, wet
____ 18. Mechanical weathering is more rapid in a ____ climate.
a.
dry
c.
cold
b.
hot
d.
humid
____ 19. Soil erosion can be slowed by ____.
a.
no-till farming
c.
plowing at least three times a year
b.
cutting trees from the middle of fields
d.
farming on steeper slopes
____ 20. The organic matter in humus is made of ____.
a.
dead worms
c.
roots
b.
stems
d.
all of the above
____ 21. The rate of weathering depends upon the area's ____.
a.
oxygen
c.
water
b.
climate
d.
soil
____ 22. The rock and mineral fragments in soil come from rock that has been ____.
a.
blasted
c.
weathered
b.
carved
d.
chemically treated
____ 23. On steep slopes and mountains, ____ helps reduce erosion by creating level areas for crops.
a.
a shelter belt
c.
mulching
b.
strip cropping
d.
terracing
____ 24. The difference between mechanical and chemical weathering is ____.
a.
the length of time each takes to break up a rock
b.
that only chemical weathering involves water
c.
the way they affect the makeup of a rock
d.
all of the above
____ 25. Soils in ____ contain little organic material and are thin.
a.
tropical areas
c.
prairies
b.
deserts
d.
temperate forests
____ 26. Plants cannot grow without ____.
a.
rocks
c.
moss
b.
soil
d.
pesticides
____ 27. ____ regions are especially vulnerable to erosion because their soils are useful to farmers for only a few years before their nutrients are gone.
a.
Desert
c.
Mountain
b.
Tropical
d.
Prairie
____ 28. The mass of clay, silt, sand, and boulders that covers much of the United States was deposited by ____.
a.
farming
c.
ice wedging
b.
glaciers
d.
huge bulldozers
____ 29. Ice wedging is brought about by ____.
a.
carbonic acid freezing on rocks
c.
water freezing and thawing
b.
water and oxygen reacting
d.
rocks colliding with each other
____ 30. Minerals found in the B horizon were dissolved in water and carried there by a process called ____.
a.
oxidation
c.
weathering
b.
leaching
d.
littering
____ 31. Oxidation occurs when materials containing ____ are exposed to oxygen and water.
a.
iron
c.
kaolinite
b.
carbonic acid
d.
all of the above
____ 32. In bottomlands where water is plentiful, soil is often ____.
a.
thin
c.
thick
b.
rocky
d.
light
____ 33. The B horizon is ____.
a.
rockier than the C horizon
c.
lighter than the A horizon
b.
richer in humus than the A horizon
d.
thinner than the C horizon
____ 34. Plants don't grow as well when ____ has been lost.
a.
clay
c.
parent rock
b.
topsoil
d.
slope
____ 35. ____ is a factor that affects soil development.
a.
Time
c.
Type of rock
b.
Slope
d.
all of the above
____ 36. The ____ horizon has smaller rock and mineral particles than the other layers.
a.
A
c.
C
b.
B
d.
D
____ 37. Below the C horizon is ____.
a.
topsoil
c.
clay
b.
rock
d.
humus
____ 38. In wet climates, granite weathers more slowly than ____.
a.
marble
c.
kaolinite
b.
feldspar
d.
calcite
____ 39. Mechanical weathering ____.
a.
breaks apart rocks by physical processes
b.
occurs when chemical reactions dissolve or change the minerals in rocks
c.
occurs when iron is exposed to oxygen and water
d.
none of the above
____ 40. Chemical weathering ____.
a.
is caused by freezing and thawing
b.
breaks apart rocks by physical processes
c.
occurs when chemical reactions dissolve or change the minerals in rocks
d.
none of above
____ 41. In areas where freezing and thawing occur frequently, rocks weather rapidly because of the ____ of freezing water.
a.
evaporation
c.
leaching
b.
expansion
d.
oxidation
____ 42. When water mixes with carbon dioxide gas in the air or soil, ____ forms.
a.
carbonic acid
c.
calcite
b.
lactic acid
d.
oxygen
____ 43. At construction sites, workers often reduce erosion by ____.
a.
covering exposed ground
c.
planting trees
b.
spraying water on bare soil
d.
none of the above
____ 44. Because desert soils contain little organic material, their soil profiles have ____ horizons.
a.
thick
c.
thin
b.
no
d.
b or c
____ 45. ____ turns and loosens soil, improving it for crops, but leaving soil vulnerable to erosion.
a.
Grazing
c.
Plowing
b.
No-tilling farming
d.
Terracing
____ 46. Soil erosion occurs ____.
a.
where animals eat away all the plants
c.
on steep slopes
b.
when forests are removed
d.
all of the above
____ 47. When farmers leave plant stalks in the field to reduce soil erosion, it is called ____.
a.
contour farming
c.
no-till farming
b.
plowing
d.
terracing
____ 48. Soil is a mixture of weathered rock and ____.
a.
water and air
c.
mineral fragments
b.
decayed organic matter
d.
all of these
____ 49. The layer of soil that contains more humus and smaller rock and mineral particles than the other layers is the ____ horizon.
a.
A
c.
C
b.
B
d.
D
____ 50. All of the following are direct causes of mechanical weathering except ____.
a.
ice
c.
water
b.
tree roots
d.
oxygen
____ 51. Over thousands of years, ____ has chemically weathered limestone, creating caves.
a.
kaolinite clay
c.
oxidation
b.
carbonic acid
d.
sediment
____ 52. Chemical weathering is more rapid in a ____ climate.
a.
dry
c.
cold
b.
tropical
d.
moderate
____ 53. Mechanical weathering is more rapid in a ____ climate.
a.
dry
c.
cold
b.
tropical
d.
moderate
____ 54. When livestock eat all the grass on the land, the land is said to be ____.
a.
overgrazed
c.
weathered
b.
leached
d.
all of these
____ 55. The organic material in humus includes ____.
a.
plant leaves and stems
c.
sand
b.
weathered rocks
d.
air
____ 56. How fast weathering occurs depends on the ____ of an area.
a.
oxygen
c.
water
b.
climate
d.
vegetation
____ 57. In no-till farming, plant stalks are ____.
a.
destroyed
c.
left in the field
b.
covered with water
d.
plowed under
____ 58. Compared to the A horizon in a soil profile, the B horizon ____.
a.
is lighter in color
b.
contains material leached from the A horizon
c.
contains less humus
d.
all of these
____ 59. The difference between mechanical and chemical weathering is ____.
a.
the length of time each takes to break up rock
b.
that each occurs in different parts of the world
c.
only one changes the chemical composition of a rock
d.
that only chemical weathering involves water
____ 60. Soil horizons in deserts are ____ than soil horizons in wetter climates.
a.
thicker
c.
darker
b.
thinner
d.
more fertile
____ 61. Forest harvesting creates the most severe problems in ____ regions.
a.
desert
c.
urban
b.
tropical
d.
mountain
____ 62. Agricultural practices that slow soil erosion include ____.
a.
planting shelter belts of trees
b.
plowing
c.
allowing livestock to graze wherever they want
d.
leaving soil open to rain
____ 63. Causes of soil erosion include ____.
a.
wind
c.
removal of vegetation
b.
water
d.
all of these
____ 64. Ice wedging is caused by ____.
a.
acid freezing on rocks
c.
water freezing and thawing
b.
water and oxygen reacting
d.
all of these
____ 65. The minerals found in the B and C horizons were dissolved in water and carried down to those soil layers by a process called ____.
a.
oxidation
c.
weathering
b.
leaching
d.
precipitation
____ 66. Oxidation requires a combination of three things: ____.
a.
iron, oxygen, and water
c.
rock, oxygen, and water
b.
iron, carbon dioxide, and water
d.
acid, iron, and oxygen
____ 67. An area's climate is its ____.
a.
high and low temperatures
c.
pattern of weather over many years
b.
annual rainfall
d.
daily weather over the last year
The following questions are based on a soil profile.
____ 68. The B horizon is ____.
a.
darker than A
c.
lighter than A
b.
darker than C
d.
lighter than C
____ 69. The A horizon is high in ____.
a.
clay
c.
rocks
b.
organic materials
d.
leached materials
____ 70. Leaching occurs mainly in the ____ horizon.
a.
A
c.
C
b.
B
d.
D
____ 71. Weathering occurs most rapidly in the ____ horizon.
a.
A
c.
C
b.
B
d.
D
____ 72. Below the C horizon is ____.
a.
humus
c.
clay
b.
rock
d.
more soil
____ 73. The ____ horizon consists mostly of parent rock.
a.
A
c.
C
b.
B
d.
D
Completion
Complete each statement.

Figure 7-1
74. The correct labels for the numbers in Figure 7-1 are (1) ____________________, (2) ____________________, and (3) ____________________.
75. The three horizons in Figure 7-1 make up a soil ____________________.
76. The ____________________ horizon in Figure 7-1 contains the most humus.
77. The ____________________ horizon shown in Figure 7-1 is most like the parent material.
78. The most leaching of minerals occurs from the ____________________ horizon into the ____________________ horizon.
79. Topsoil is the ____________________ horizon in Figure 7-1.
80. The ____________________ horizon shown in Figure 7-1 has the least organic matter.
81. Most plant roots grow in the ____________________ horizon.
82. The A horizon may be covered with leaves, twigs, and other organic matter called ____________________.
83. Small pieces of rock such as sand, silt, and clay are called ____________________.
84. ____________________ is the pattern of weather that occurs in a particular area over many years.
85. ____________________ is harmful because plants do not grow well when topsoil has been lost.
86. When farm animals eat the grass on land until there is almost no ground cover, it is called ____________________.
87. ____________________ is made of dead plant and animal matter that has decayed due to bacteria and fungi.
88. Planting along the natural slope of the land to reduce soil erosion is called ____________________.
89. Eroded soil can enter ____________________, causing them to fill up with sediment.
90. all the horizons of a soil ____________________
91. each layer in a soil profile ____________________
92. type of weathering that occurs when reactions dissolve the minerals in rocks ____________________
93. a mixture of weathered rock, decayed organic matter, mineral fragments, water, and air ____________________
94. ice breaking apart a rock ____________________
95. when materials containing iron are exposed to water and oxygen ____________________
96. leaves, twigs, and organic matter that may be changed to humus ____________________
97. decayed organic matter that turns into a dark-colored material ____________________
98. the removal of minerals that have been dissolved in water ____________________
99. weathering that occurs when rocks are broken apart by physical processes ____________________
100. surface processes that work to break down rock ____________________
101. What does weathering create? ____________________
Use the following words to fill in the blanks below. Not all the terms are used.
soil
leaching
terracing
mechanical weathering
carbonic acid
horizon
no-till farming
ice wedging
soil profile
shelter belts
chemical weathering
oxidation
overgrazing
humus
contour farming
102. When unpainted iron lawn furniture sits outside in the rain and begins to rust, ____________________ has occurred.
103. ____________________ has occurred when chemical reactions dissolve the minerals in rocks or change them into different minerals.
104. ____________________ is the process by which water moves minerals down from one soil layer to another.
105. Water freezing and cracking rock and tree roots spreading through rock are examples of _________________________.
106. When weathered rock, decayed organic matter, mineral fragments, water, and air are combined, ____________________ is formed.
107. Mountain peaks, where water freezes and thaws often, are often weathered by ____________________.
108. ____________________ is organic matter made of decayed plants and animals.
109. You can see the different layers of soil that make up a ____________________ on a hillside where the soil and rock have been exposed.
110. Planting along the natural contours of the land on gentle slopes is called ____________________.
111. Leaving plant stalks undisturbed in the field to cover the soil is known as ____________________.
112. Wind erosion of the land can be reduced by planting ____________________ of trees.
Short Answer
113.
Fernando carries out an experiment about soil erosion. With a garden hose he sprays water for 30 seconds on a small pile of sand in his brother's sandbox. The water quickly flattens the pile. He then sprays water on a sloped area of the yard that is sandy, but covered with grass. After 30 seconds, the slope has not changed, and very little sand flows out at the bottom of the slope. What has Fernando demonstrated?
114.
In what ways do burrowing animals affect soil?

Figure 7-2
115.
In Figure 7-2, which picture shows ice wedging: A, B, or C?
116.
In Figure 7-2, which picture shows weathering that involves carbonic acid: A, B, or C?
117.
In Figure 7-2, are the animal burrows in B an example of chemical or mechanical weathering?
118.
Describe the factors that influence the development and type of soil in a certain area.
119.
What human activities lead to soil erosion?
120.
Name three things farmers can do to reduce soil erosion.
121. How does climate affect the rate of weathering of rocks?
122. List five factors that affect the type of soil in a particular area.
123. What would happen to life on Earth if there were no soil?
124. What farming activities have contributed to soil loss? How can farmers prevent this loss?
125. Describe each of the three soil layers in a soil profile.
Choose Cause or Effect for each pair of sentences below. Then combine the two sentences to make one sentence that shows the cause-and-effect relationship.
126. ____________________ Wedges form and the rock breaks apart.
____________________ Plants grow into cracks in rocks.
127. ____________________ Wind and water are able to carry away the topsoil.
____________________ Cattle eat all the grass on the land.
128. ____________________ The area has a rainy climate and a lot of plants.
____________________ The soil is rich with humus.
129. List the steps in soil development.
130. Explain two ways to reduce soil erosion on slopes.
Essay
131.
In what ways can people prevent soil erosion?
132. Why is weathering important?

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.