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Fossil Types
Dating Rocks
Events in Geologic Time
The Geologic Time Scale
Miscellaneous
100

The preserved remains or traces of an organism.

What is a fossil.

100

The age of a rock compared to other rocks.

approximate age or relative age

What is relative age.

100
An event in which many types of living things become extinct at the same time.
What is a mass extinction.
100

A record of the life forms and geologic events in Earth's history.

geographic time scale

geologic time scale

history of the Earth time scale

What is the geologic time scale.

100

The extinction of dinosaurs gave warm-blooded vertebrates called ___________ a chance to become abundant.

What are mammals.

200

A hollow imprint that shows the shape of an organism.


mold or cast

What is a mold.

200
Useful fossils that help to tell the relative ages of the rocks around them.
What are index fossils.
200

The end of one era and the beginning of a new era is usually caused by a ________ _______________ .

What is a mass extinction.

200

Scientists hypothesize that Earth formed at the same time as the other planets and the sun, roughly _________ billion years ago.

4.4 

4.5

4.6

What is 4.6

200

What are the best types of rocks for radioactive dating?

igneous rocks

sedimentary rocks

metamorphic rocks

What are igneous rocks.

300

An example of this type of fossil would be footprints.

What is a trace fossil.

300

An intrusion in always _________ than the rocks around it.


younger or older

What is younger.

300

The subdivisions of eras are called ______________ .


periods

epochs


What is periods.

300

Reptiles, such as dinosaurs, were so successful during the _______________ Era that the time is often called the age of Reptiles.

Mesozoic

Cenozoic

Paleozoic

What is Mesozoic.

300

Life on Earth first began in the ______________ Period.

Precambrian

Paleozoic 

What is Precambrian.

400
A fossil formed when minerals replace all or part of an organism.
What is a petfrified fossil.
400

The method used to determine the absolute age of rocks.

relative dating

radioactive dating

What is radioactive dating.

400
What do most scientists think caused the mass extinction at the end of the Cretaceous Period?
What is an object from space struck Earth.
400

Jawless fish were earth's first ______________, or animals with backbones.

What are vertebrates.

400

A gap in the geologic record where some rocks layers have been lost due to erosion.

conformity

unconformity

What is an unconformity.

500

The change of living things over time.

What is evolution?

500
Explain how the Law of Superposition is used to determine the relative ages of sedimentary rock layers.
What is the oldest layer is that the bottom, and each higher layer is younger than the rocks below it.
500

Earth's atmosphere, oceans, and continents began to form during the first several hundred millions years of ______________ .


Cenozoic time

Precambrian time

What is Precambrian Time.

500

Certain ammonites are used an __________ ___________ because they lived in many different areas but only for a brief time.

index fossils

trace fossils

What are index fossils.

500

The present day is part of the ____________ Era.


Paleozoic

Mesozoic

Cenozoic

What is Cenozoic.