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13 terms

KS Glossary Terms - Chapter 12 History of Life on Earth

KS Dept of Education - Life Sci Glossary Terms
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Big Bang Theory
the earliest event in widely held scientific model of the origin of the known
universe.
fossil record
the collection of preserved organisms or their traces stored in the lithosphere providing an image of past life and conditions on Earth
geologic time
the period of time that include the physical formation of Earth through present time.
invertebrates
organisms that do not have a backbone
mass extinction
loss of a majority of species due to a rare catastrophic event
multicellular
composed of many cells, each having a specific function
plate tectonics
theory used to describe the movement of Earth's crustal plates
principle of superposition
concept that in an undisturbed rock sequence, more recent rock layers are deposited on top of older rock layers
radioactive dating
the estimation of age of an object by comparison of the ratios of appropriate isotopes with known rates of decay
radioactive decay
change over time in an atom due to loss of atomic particles and/or energy
relative dating
the use of cross-comparisons of rock layers to establish older and younger geologic layers
unicellular
generally, primitive organisms that remain one-celled and do not differentiate
vertebrates
those animals that possess an internal skeleton