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21 Cards in this Set

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The death of an entire species.


A paleontologist is a scientist who studies fossils

Relative dating

Relative dating falls under the sub-discipline of geology known as stratigraphy. Stratigraphy is the science of rock strata, or layers. Layering occurs in sedimentary rocks as they accumulate through time, so rock layers hold the key to deciphering the succession of historical events in Earth's past

Index fossils

a fossil that is useful for dating and correlating the strata in which it is found

Radiometric dating

Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which characterize the light's interaction with the human eye


an indefinitely long period of time; age

Half life

Half‑life is the amount of time required for the amount of something to fall to half its initial value.


a long and distinct period of history with a particular feature or characteristic


Eras are subdivided into periods which range in length from nearly 100 million years to just under 2 million years


a group of organisms believed to have evolved from a common ancestor, according to the principles of cladistics

2 forces that shaped life and Planet Earth.

Gravity, ocean and atmosphere


major evolutionary change. The term applies mainly to the evolution of whole taxonomic groups over long periods of time.

Mass extinction

mass extinction definition. Any of several events in the Earth's past in which large numbers of species (in some cases, up to eighty percent) became extinct. Note: The most famous mass extinction included the destruction of the dinosaurs sixty-five million years ago.

Background extinction

Background extinction rate, also known as 'normal extinction rate', refers to the standard rate of extinction in earth's geological and biological history before humans became a primary contributor to extinctions. This is primarily the pre-human extinction rates during periods in between major extinction events


the hypothesis that evolution proceeds chiefly by the accumulation of gradual changes (in contrast to the punctuationist model)

Punctuated Equilibrium

the hypothesis that evolutionary development is marked by isolated episodes of rapid speciation between long periods of little or no change.

Convergent evolution

Convergent evolution is the independent evolution of similar features in species of different lineages. Convergent evolution creates analogous structures that have similar form or function, but that were not present in the last common ancestor of those groups.

Adaptive radiations and examples

the diversification of an ancestral group of organisms into a variety of related forms specialized to fit different environments or ways of life, each often further diversifying into more specialized types


the influence of closely associated species on each other in their evolution.

RNA world Hypothesis

The RNA world refers to the self-replicating ribonucleic acid (RNA) molecules that were precursors to all current life on Earth. It is generally accepted that current life on Earth descends from an RNA world, although RNA-based life may not have been the first life to exist.

Endosymbiotic theory

Symbiogenesis, or endosymbiotic theory, is an evolutionary theory that explains the origin of eukaryotic cells from prokaryotes. It states that several key organelles of eukaryotes originated as a symbiosis between separate single-celled organisms