Chapter 7: Change Over Time

2. A group of organisms that are physically similar and can make mate with each other and reproduce.
7. The preserved remains or traces of an organism that lived in the past.
12. A difference between individuals of the same species.
13. The comparison of the structures of different organisms.
14. Body parts that are structurally similar in related species.
15. The process of grouping things based on their similarities.
16. The gradual change in a species over time.
17. The scientific study of how living things are classified.
18. The disappearance of all members of a species from Earth.
20. A classification grouping that consists of a number of similar, closely related species.
22. A scientist who studies fossils.
24. A behavior or physical characteristic that allows an organism to survive or reproduce in its environment.

1. The system for naming organisms in which each organism is given a unique, two-part scientific name.
3. A fossil formed when minerals replace all or part of an organism.
4. The theory that evolution occurs slowly but steadily.
5. A type of fossil formed when a shell or other hard part of an organism dissolves, leaving an empty space in the shape of the part.
6. A type of fossil that provides evidence of the activities of ancient organisms.
8. A well tested concept that explains a wide range of observation.
9. The theory that species evolve during short periods of rapid change.
10. A type of fossil that forms when a mold becomes filled in with minerals that then harden.
11. A process by which individuals that are better adapted to their environment are more likely to survive and reproduce than others of the same species.
19. An organism whose cell contain nuclei.
21. The specific environment that provides the things an organism needs to live, grow, and reproduce.
23. An organism whose cells lack a nucleus and some other cell structure.