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Principle of uniformitarianism
Earth processes occurring today are similar to those that occurred in the past
Law of Superposition
in undisturbed rock layers, the oldest rocks are on the bottom and the youngest rocks are on the top
a space in a rock that has the shape of the remains of a living thing that once occupied that space.
a model in the shape of a living thing or its remains, it forms when minerals or rock particles fill the space
is a method using radioisotope carbon-14 to determine the age of objects such as fossils or rocks
the process in which organic material is changed into inorganic material such as a fossil
geologic time scale
the division of Earth history into blocks of time--eons, eras, periods, and epochs. The time scale was created using relative dating principles.
Pre-Cambrian time covers from 4.6 billion to 544 million years ago. During this time life developed as bacteria and softbodied, multicelled organisms. First mass extinction probably occurred near the end of the Precambrian
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