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| Evolutionary change above the species level. Examples of macroevolutionary change include the origin of a new group of organisms through a series of speciation events and the impact of mass extinctions on the diversity of life and its subsequent recovery. |
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| An abiotic precursor of a living cell that had a membrane-like structure and that maintained an internal chemistry different from that of its surroundings. |
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| An RNA molecule that functions as an enzyme, such as an intron that catalyzes its own removal during RNA splicing. |
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| A method for determining the absolute age of rocks and fossils, based on the half-life of radioactive isotopes. |
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| The amount of time it takes for 50% of a sample of a radioactive isotope to decay. |
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| The division of Earth's history into time periods, grouped into three eons- Archaean, Proterozoic, and Phanerozoic- and further sundivided into eras, periods, and epochs. |
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| Layered rock that results from the activities of prokaryotes that bind thin films of sediment together. |
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| The theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism. |
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| A hypothesis for the origin of eukaryotes consisting of a sequence of endosymbiotic events in which mitochondria, chloroplasts, and perhaps other cellular structures were derived from small prokaryotes that had been engulfed by larger cells. |
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| A relatively brief time in geologic history when many present-day phyla of animals first appeared in the fossil record. This burst of evolutionary change occured about 535-525 million years ago and saw the emergence of the first large, hard-bodied animals. |
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| The theory that the continents are part of great plates of Earth's crust that float on the hot, underlying portion of the mantle. Movements in the mantle cause the continents to move slowly over time. |
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| The supercontinent that formed near the end of the Paleozoic era, when plate movements brought all the landmasses of Earth together. |
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| The elimination of a large number of species throughout Earth, the result of global enviornmental changes. |
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| Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities. |
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| Evolutionary change in the timing or rate of an organism's development. |
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| The retention in an adult organism of the juvenile features of its evolutionary ancestors. |
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| Any of the master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the developmental fate of groups of cells. |
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