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Chapter 17 - The History of Life
Across
1. process by which unrelated organisms independently evolve similarities when adapting to similar environments
3. process by which a single species or small group of species evolves into several different forms that live in different ways; rapid growth in the diversity of a group of organisms
5. method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock
6. distinctive fossil used to compare the relative ages of fossils
7. theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms
8. pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
9. length of time required for half of the radioactive atoms in a sample to decay
10. event in which many types of living things become extinct at the same time
Down
1. process by which two species evolve in response to changes in each other
2. technique in which scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains
4. large-scale evolutionary changes that take place over long periods of time