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Species a group of similar organisms that can mate with each other and produce fertile offspring
fossil the preserved remains or traces of an organism that lived in the past
adaptation a trait that helps an organism survive and reproduce
evolution the gradual change in a species over time
scientific theory a well-tested concept that explains a wide range of observations
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
variation any difference between individuals of the same species
homologous structure similar structures that related species have inherited from a common ancestor
branching tree a diagram that shows how scientists think different groups of organisms are related
petrified fossils remains that become buried in sediments that are actually changed to rock
mold hollow space in sediment in the shape of an organism or part of an organism
cast a copy of the shape of the organism that made the mold
relative dating a technique used by scientists to tell which of two fossils is the oldest
radioactive dating technique used by scientists that actually determines the actual age of fossils
half-life the time it takes for for half of the atoms in a sample to decay
fossil record the millions of fossils that scientists have collected
extinct no members of a species are still alive
gradualism evolution occurs slowly but steadily
Created by: carlocrew