Preservation
Fossils
Absolute Age
Geologic Time Scale
Fossil Fuels
100
hard parts, such as shells and bones
What animal parts are most often preserved?
100
remains or traces of an organism that living long ago
What are fossils?
100
the true ago of a rock or fossil
What is absolute age?
100
outline of the major divisions in Earth's history
What is geologic time scale?
100
natural fuel that was formed from the remains of living things
What are fossil fuels?
200
sediments, frozen soil and ice, tar, and sap
What four things help preserve the remains of organisms?
200
sedimentary rock
What kind of rock contains the most fossils?
200
fossils that can be used to help determine the relative age of rock layers
What are index fossils?
200
4.6 billion years
How old is the Earth?
200
light and heat
What two forms of energy are given off when hydrocarbons are burned?
300
animals try to drink water that covers tar pits or when they try to pull out other trapped animals to eat
How are animals trapped in tar pits?
300
states that each undisturbed sedimentary rock layer is older than the layer above it.
What is the law of superposition?
300
Quarternary
What is the most recent period of time?
300
peat, soft coal, and hard coal
What are the three basic stages of coal formation?
400
hardened tree sap
What is amber made from?
400
bones, shells, teeth, tracks, burrows, coprolites, gastroliths
What are four kinds of fossils?
400
a radioactive element changes into another more stable element by giving off particles and energy
What is radioactive decay?
400
Cenozoic, Mesozoic, Paleozoic, Precambrian
What eras make up the geologic time scale?
400
microorganisms that were buried in sediments
What types of ancient organisms formed oil and natural gas?
500
insects
What else besides plants are usually preserved in amber?
500
Fossils show that Earth's surface and climate have changed over time. Warm environments, for example, have turned to cold. Some mountain crust was once ocean floor.
What do fossils tell us about living things?
500
The species existed for only a short time in Earth's history, many fossils of the species are found in rock layers, the species was widespread on Earth, the species must be unique
What four qualities make up an index fossil?
500
More information is available for the most recent period so that finer distinctions can be made
Why are only the most recent periods divided into epochs?
500
gas is less dense than liquid oil
Why is natural gas found above petroleum in an oil deposit?
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