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DSMS Life History
Earth and Life History
Word | Definition |
---|---|
sedimentary rock | rock formed when sediment is lithified |
paleontologist | a scientist who studies fossils and ancient life |
rock cycle | the process involving the formation and recycling of rock |
extinct | when all of the members of a species die |
oxygen | gas produced by anaerobic prokaryotes during Precambrian time |
ozone | forms a layer in the atmosphere that shields solar radiation |
anaerobic | living without oxygen |
uniformitarianism | the idea that geologic processes that occur today also occurred in the past |
igneous rock | rock formed when lava or magma cools |
superposition | principle that states younger rocks are on top of older rocks |
Precambrian time | period when there was no oxygen in the Earth's atmosphere |
Paleozoic era | era when plants and animals first lived on land |
Cenozoic era | era dominated by mammals |
Pangaea | a large landmass that contained all the present-day continents |
metamorphic rock | rock formed when existing rock is squeezed or partially melted |
absolute dating | dating method that determines a fossil or events exact age |
relative dating | dating method that compares the age of one specimen or event to another |
geologic time scale | organizes the history of life on Earth |
plate tectonics | the study of the movement of Earth's continental plates |
fossil | the solidified remains or imprints of once-living organisms |
mass extinction | when a large number of species dies off in a short period of time |
weathering | the gradual breakdown of rock, usually by wind or water |
erosion | when sediment is carried away, usually by wind or water |
catastrophism | the idea the geologic events occur suddenly |
Mesozoic Era | era dominated by dinosaurs |
crystallization | when a solid forms into an organized structure called a crystal |