1. adaptive radiation - 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.
2. coevolution - process by which two species evolve in response to changes in each other.
3. convergent evolution - process by which unrelated organisms independently evolve similarities when adapting to similar environments.
4. endosymbiotic theory - theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms.
5. era - one of several subdivisions of the time between the Precambrian and the present.
6. extinct - term used to refer to a species that has died out.
7. fossil record - information about past life, including the structure of organisms, what they ate, what ate them, in what environment they lived, and the order in which they lived.
8. geologic time scale - scale used by paleontologists to represent evolutionary time.
9. half-life - length of time required for half of the radioactive atoms in a sample to decay.
10. index fossil - distinctive fossil used to compare the relative ages of fossils.
11. macroevolution - large-scale evolutionary changes that take place over long periods of time.
12. mass extinction - event in which many types of living things become extinct at the same time.
13. microfossil - microscopic fossil.
14. paleontologist - scientist who studies fossils.
15. period - unit of time into which eras are subdivided.
16. proteinoid microsphere - tiny bubble, formed of large organic molecules, that has some characteristics of a cell.
17. punctuated equilibrium - pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change.
18. radioactive dating - technique in which scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains.
19. relative dating - method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock.
2. coevolution - process by which two species evolve in response to changes in each other.
3. convergent evolution - process by which unrelated organisms independently evolve similarities when adapting to similar environments.
4. endosymbiotic theory - theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms.
5. era - one of several subdivisions of the time between the Precambrian and the present.
6. extinct - term used to refer to a species that has died out.
7. fossil record - information about past life, including the structure of organisms, what they ate, what ate them, in what environment they lived, and the order in which they lived.
8. geologic time scale - scale used by paleontologists to represent evolutionary time.
9. half-life - length of time required for half of the radioactive atoms in a sample to decay.
10. index fossil - distinctive fossil used to compare the relative ages of fossils.
11. macroevolution - large-scale evolutionary changes that take place over long periods of time.
12. mass extinction - event in which many types of living things become extinct at the same time.
13. microfossil - microscopic fossil.
14. paleontologist - scientist who studies fossils.
15. period - unit of time into which eras are subdivided.
16. proteinoid microsphere - tiny bubble, formed of large organic molecules, that has some characteristics of a cell.
17. punctuated equilibrium - pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change.
18. radioactive dating - technique in which scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains.
19. relative dating - method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock.