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Life Science Packet D
Section 1 & 2
34
Science
7th Grade
03/16/2008

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Cards

Term
Fault
Definition
A break or crack along which rocks move
Term
Absolute Age
Definition
the number of years since a rock formed
Term
Law of Superposition
Definition
Way to determine relative ages of rocks
Term
Relative Age
Definition
Age of a rock compared with the age of other rocks
Term
Index Fossil
Definition
Fossils used to determine the relative ages of other rock layers
Term
Intrusion
Definition
A hardened layer of magma that coold into a mass of igneous rock
Term
Extrusion
Definition
A hardened layer of lava
Term
Unconformity
Definition
A place where an eroded surface is in contact with a newer rock layer
Term
Rock Cycle  
Definition
process by which rocks can be changed from one form into another
Term
5 types of fossils  
Definition
Carbon film, trace fossils, petrified fossils, mold and cast, preserved
Term
Carbon film fossil
Definition
xtremely thin coating of carbon on rock. All living things contain carbon. Sediment buries an organism, than squeezes almost all of it away, leaving carbon film
Term
Trace Fossil
Definition
provide evidence of the activities of ancient organisms. Footprint is example-provides clues of size and behavior
Term
Preserved Remains
Definition
Preserved the remains of organisms with little or no change. Example tar, amber and freezing
Term
3 Ways remains of organism can be preserved?  
Definition
Tar, sticky oil seeped from earth's surface, animals became stuck. Amber resin or sap from trees trap insect. Freezing found remains in very cold regions.
Term
Petrified Fossils
Definition
Turned to stone, sediment covered the wood, water rich in dissolved minerals seeped into cells causing some of original wood to remain hardened and preserved.
Term
Another type of Petrified fossils
Definition
Formed by replacement, minerals making copy of organism
Term
Mold and Casts
Definition

Copy shape of organisms.

Mold is a hollow area in sediment in the shape of an organism or part of an organism-mold forms when hard part of the organism is buried in sediment.

Cast is a copy of the shape of an organism, the mold is filled with minerals to form cast

Term
Why are fossils important?
Definition

Provide picture of Earth's environment in past,

clues of climate

and

learn changes of earth's surface 

Term
What are fossils?
Definition
Remains or Traces of an organism
Term
Paleontologists
Definition
Scientists who study fossils
Term
How do fossils form?
Definition
Form from animals or plants that once lived in or near quiet waters, such as swamps, lakes, or shallow seas where SEDIMENTS build up and by being protected from decay.
Term
 What is Rock made from?
Definition
mixtures of minerals and other materials
Term
Name 3 major rock groups.
Definition
Igneous rock, Sedimentary and metamorphic
Term
How does Igneous rock form
Definition
molten material cools and hardens below/on surface
Term
How does sedimentary rock form?
Definition
particles of other rocks or remains of plants and animals are pressed and cemented together, below surface
Term
How does metamorphic rock form?
Definition
existing rockis changed by heat, pressure or chemical reactions deep underground.
Term
What does unconformity show?
Definition
Shows where  some rock layers have been lost because of erosion
Term
How do geologists determine the relative age of rocks?
Definition

by the Law of Superposition-which is -

in horizontal sedimentary rock layers -the oldest layer is at the bottom. Each higher layer is younger than the layers below it.

Term
What gives other clues to the relative ages of rocks?
Definition
Intrusions, extrusions and faults.
Term
Is a fault younger or older thant the rock it cuts through?
Definition
Always younger
Term

 

What characteristics are necessary for a fossil to be considered an Index Fossil? 2 reasons.  

Definition
It must be widely distributed in many different areas and represent a type of organism that existed only briefly.
Term
Name an example of an Index Fossil
Definition
A trilobites with large eyes.
Term
In which type of rock are fossils usually found?
Definition
Sedimentary
Term
What drives the rock cycle:
Definition
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