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species a group of similar organisms whose members can mate with one another and produce fertile offspring
evolution the gradual change in a species over time
natural selection the process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species
adaptation a characteristic that helps an organism survive in its environment or reproduce
scientific theory a well-tested concept that explains a wide range of observations
variation any difference between individuals of the same species
fossil the preserved remains or traces of an organism that lived in the past
sedimentary rock a type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together
relative dating a technique used to determine which of two fossils is older
absolute dating a technique used to determine the actual age of fossils
half-life the time it takes for half of the atoms of a radioactive element to decay
fossil record the millions of fossils that scientists have collected
extinct a species that does not have any living members
gradualism the theory that evolution occurs slowly but steadily
punctuated equilibria the theory that species evolve over short periods of rapid change
homologous structure body parts that are structurally similar in related species; provide evidence that the structures were inherited from a common ancestor
branching tree a diagram that shows how scientists think different groups of organisms are related
Created by: skrebbeks