Across
- 2. a group of similar organisms that can mate with each other and produce fertile offspring.
- 4. is a well tested concept that explains a wide range of observations.
- 5. is the process by which individual that are better adapted to their environment are more likely to survive and reproduce than other members of the same species.
- 6. similar structures that related species inherited from common ancestors.
- 8. a hollow space in the sediment in the shape of an organism or part of an organism
- 10. gradual change in a species over time.
- 11. any difference between individual of the same species.
- 13. is a diagram that shows how scientist thin different groups of organisms are related.
- 14. which are unstable elements that decay, or break down, into different elements
- 16. is a copy of the shape of the organism that make the mold.
- 17. minerals dissolved in the water soak into the buried remains, the minerals replace the remains, changing them into rock.
- 19. a trait that helps an organism survive and reproduce
- 20. the time it take s for half of the atoms in a sample to decay.
Down
- 1. fossils that scientist have collected
- 3. account for the gaps in the fossil record. Rapid evolution
- 7. proposes that evolution occurs gradually over time.
- 9. Rocks that are found near the fossil contain radioactive elements, they test this element to determine the age
- 12. can only be used when rock layers have been preserved in their original sequence
- 15. no members of a particular species is still living.
- 18. is the preserved remains or remains of an organism that lived in the fast.