Across
- 1. The small differences in traits.
- 3. The study of the history of Earth (and life on Earth) as recorded through rocks and the fossil record.
- 6. In this type of selection, humans select which variations they find useful and breed those specific individuals to change the traits of populations over time.
- 8. An organism’s ability to survive and reproduce.
- 9. A variation of a trait that helps an organism survive and reproduce in its environment (increases its fitness).
- 10. The process by which organisms in nature best adapted to their environment survive and leave more offspring is called _________ selection.
- 12. The study of the development of embryos across different species.
- 14. According to the principle of common decent, all species descended from ________ ancestors, and exhibit diversity due to adaptation and natural selection.
- 16. The law of this states that new rock forms on top of old rock, thus fossils found deeper in rock layers are older.
- 17. The preserved remains or traces of ancient organisms in rocks.
Down
- 2. A method of dating how old a fossil or rock is by comparing it to the layers of rock around it.
- 4. As organisms evolve there are often these remaining structures that haven’t fully disappeared, but have lost most or all of their original purpose, such as the leg bones in whales or tailbones in humans.
- 5. The first species, an amphibian, to walk on land. All land animals are descended from it.
- 7. These structures look similar in various species, but have different functions, and provide evidence that they share a common ancestor. An example are the forelimbs of mammals.
- 11. A method of dating how old a fossil or rock is by measuring the amount of radioactive isotopes remaining and calculating the age based on the element's half life.
- 13. This naturalist discovered the theory of evolution by natural selection.
- 15. The change in a species’ inheritable characteristics over many generations.