Across
- 5. structure -similar structure that related species have inherited from common ancestor
- 9. Darwin-British nationalist who formulate the theory of evolution by natural selection
- 10. - the disappearance of all members of a species from earth
- 12. -the theory that evolution occurs slowly but steadily
- 14. fossil -a fossil formed when minerals replace all or part of an organism
- 15. - behavior or physical characteristic that allows an organism to survive and reproduce in its environment
- 16. - a type of fossil that forms when a mold become filled within mineral that then harden
- 17. - any different between individuals of the same species
- 19. - any change of DNA in the organism
- 20. equilibrium -The theory that species evolve during short periods of rapid change.
- 22. - the gradual change in species over time
Down
- 1. selection-a process by which individuals that are better adapted to their environment are more likely to survive and reproduce than others that are not
- 2. - 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.
- 3. a group of organisms that are physically similar and can mate with each other and produce offspring that can also mate and reproduce
- 4. dating -A technique used to determine which of two fossils is older
- 5. -the time it was ages for half of atoms in a radioactive element to decay
- 6. link -gaps in the fossil record
- 7. theory -a well-tested concept that explains a wide range of observations
- 8. tree -a diagram showing how scientists think different groups of organisms are related.
- 11. - that variety of organisms that inhabit the earth
- 13. dating -process where scientists look at the half-life of chemical contained in rocks around a fossil to determine the age of fossil
- 18. recorder -the million fossil that scientist have collect
- 21. the preserved remains or traces of an organism that lived in the past