Ch 9 View From Earth’s Past
Time Scales
Fossils
Terms
Time
Periods
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The mass extinction at
the end of this period led
to abundant new life
forms in the Mesozoic
and Cenozoic Eras
Answer
Permian Period
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How many billion of years
ago did the Earth form?
Answer
4.6 billion
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The era of time that began
65 million years ago
Answer
Cenozoic Era
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How many eons is geologic
time divided into?
Answer
4 eons
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What is the first period of
the Mesozoic Era?
Answer
Triassic Period
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The impact hypothesis states
that an _____ crashed into
Earth, making the dinosaurs
extinct.
Answer
Asteroid
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What are the most
common Precambrian
fossils?
Answer
Cyanobacteria
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Relative ages of
sedimentary rock all
around the world
created the _____
column
Answer
Geologic column
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True or False: the mass
extinction at the end of
the Permian Period led to
abundant new life forms
Answer
True
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What natural forces can
destroy fossils?
Answer
.
Tectonic Activity:
Volcanic activity,
folding, faulting,
and erosion
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What is the longest
unit of geoligic time?
Answer
Eon
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What is the gradual
development of
organisms from
preexisting organisms?
Answer
Evolution
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The ordered arrangement
of rocks in a column
Answer
Geologic column
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An episode in which a large
number of species became
extinct
Answer
Mass extinction
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What does “Ma” mean?
Answer
Millions of years
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What period is known as
the “Age of Fishes”
Answer
Devonian Period
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What divisions of geologic
time makes up about 88%
of Earth’s history?
Answer
Precambrian
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This era is known as
the “age of mammals”
Answer
Cenozoic Era
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At the end of this
period, dinosaurs
became extinct.
Answer
Cretaceous period
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This era is divided into 3 periods:,
Triassic, Jurassic and Cretaceous
Answer
Mesozoic Era
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In a geologic column, where
are the oldest rocks?
Answer
The bottom
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Geologic era that ended
about 251 million years ago
Answer
Paleozoic Era
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What is a geologic period
usually names for?
Answer
The place where
characteristic fossils were
first discovered
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True or False: Radiometric
dating can help determine
the absolute age of rocks
Answer
True
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Dinosaurs were most
abundant in this period
Answer
Jurassic Period
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