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30 Cards in this Set

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uniformitarianism
A theory that says that the same geologic processes shaping the Earth today have been at work all through Earth's history. These processes are gradual and uniform.
catastrophism
A theory that says that all geologic change happens suddenly, from catastrophes.
What do scientists use the principle of uniformitarianism to do?
To interpret the past and make predictions
What theory did the scientist James Hutton come up with?
He wrote that Earth's landforms are constantly changing as a result of geolotic processes like the breakdown of rock and the transport of sediment. This theory is now called Uniformitarianism
How did Charles Lyell influence the debate between catastrophism and uniformitarianism.
He proved that Uniformitarianism was correct: that geologic change happens gradually from the same geologic processes that have been at work on the Earth all through time.
What do they believe in modern Geology? Uniformitarianism or Catastrophism?
They realize both kinds of change work on the earth, but that most changes is gradual and uniform (uniformitarianism)
What is a fossil?
A fossil is any natrally preserved evidence of life.
What is a fossil in rock?
The hard parts of an organism's body that are left after the flesh decomposes that settle into rock sediment.
What is permineralization?
A process where minerals fill in pore spaces of an organisims tissues, or replace the tissues.
What is petrification?
a process when an organism's tissues are completely replaced by minerals. Like petrified wood that is made of stone.
How does a fossil get made with amber?
Amber is tree sap that can harden around an organism and
What is mummification?
When an organism dries out so fast their soft tissue doesn't decay, so both soft and hard parts are preserved.
What is a frozen fossil?
When an organism is frozen and preserved in a glacier or other ice. Scientists can study them when they are thawed.
What is a fossil in tar?
When an organism dies in a pit of thick oil or tar it can be preserved.
What is a trace fossil?
It is a fossil that shows evidence of an organism's activity - like a footprint or a burrow.
What is a coprolite?
It is a poop fossil, which is another kind of trace fossil that shows an organism's activity.
What is a mold?
A mold is a cavity or hole in the ground or rock where a plant or animal was buried. Sediment fills in around an object and becomes a rock with an imprint of the organism.
What is a cast?
A cast is the object created when sediment fills in a mold and becomes rock.
What kinds of information about the past do fossils give us?
1. Changes in environment, like where seas used to be.
2. Changes in life, like extinct species.
What is an index fossil?
It is a fossil of an organism that lived during a short period of time. When a scientist finds an index fossil in a layer, they can estimate the date of the layer, and then make guesses about the age of the layers above and below.
Give an example of a kind of indes fossil.
Trilobite
Phacops
Tropites
What is the geologic time scale?
It is a scale that divides the earth's 4.6 billion year history into distinct intervals, like Paleozoic, Mesozoic, and Cenozoic eras, and the Hadean, Archean, Proterozoic Eon, and Phanerozoic Eon.
What is an eon?
It is a division of time on the Geologic Time Scale. They are the largest division and represent billions of years.
Name the four eons in the earth's history.
There are four eons: Hadean, Archean, Proterozoic, and Phanerozoic.
What is an era?
It is the second largest division or geologic time, representing hundreds of millions of years.
What is a period?
It is the third largest division of geologic time, representing millions of years.
What is an epoch?
It is the fourth and smallest division of geologic time, but it still represents millions of years.
Define the Paleozoic Era.
It means "old life" and it went from about 540 to 248 million years ago. It is the first era well represented by fossils. At the end of this era 90% of all the species became extinct.
Define the Mesozoic Era.
It means "middle life" and it went from about 248 million years ago until 65 million years ago. It is the Age of Reptile Dinosaurs. Birds evolved late in the era. At the end of this era about 50% of all existing species became extinct.
Define the Cenozoic Era.
It means "recent life." It went from 65 million years ago and continues now. It is the age of Mammals. Many mammals from this era are now extinct, like wooly mammoths, saber toothed cats and giant sloths.