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a trait that helps an organism survive and reproduce


group of similar organisms that can breed and produce fertile offspring


a group of organisms of the same species populating a given area


the process of change by which new species develop from preexisting species over time

sedimentary rock

the type of rock that is made of hardened sediment


preserved remains or evidence of an ancient organism


a person who studies living things

natural selection

a process by which individuals that are better suited to their environment survive and reproduce most successfully

generation time

the period between the birth of one generation and the birth of the next generation


the formation of new species as a result of evolution

relative dating

method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock (older is usually deeper)

absolute dating

determine actual age of fossil, compare amount of radioactive element in sample to amount of element into which it breaks down


scientist who studies fossils


no longer in existence

plate tectonics

the branch of geology studying the movement of the earth's crust

Precambrian time

Name for the time in earths early history that accounts for ninety percent of earth's time, but only very simple organisms lived. White Old Boring Cells

Paleozoic era

the part of geologic time 570-245 million years ago ; invertebrates, fishes, amphibians, reptiles, ferns, and cone-bearing trees were dominant. Yellow Bizarre sea creatures

Mesozoic era

middle life (245-144 million years ago); rise of mammals and dinosaurs; the rise of birds; extinction of dinosaurs, rise of flowering plants. Red Bloody Dinosaurs

Cenozoic era

era that began about 65 million years ago, known as the "Age of Mammals" Blue New Hairy


organisms produce more offspring than can survive


offspring are genetically different

struggle to survive

there is a competition for the available resources

survival of the fittest

individuals born with the "better" traits are more likely to "win" and live

inheritance of traits

those who live are able to mate and pass their traits on to the next generation

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