chapter 14

3. structures – Body parts that no longer serve an important function but were useful to ancestors.
4. evolution – When related species become more different over time.
8. – A trait or behavior that helps an organism survive and reproduce.
12. – The idea that Earth’s features were formed by sudden natural disasters.
13. selection – The process where organisms with helpful traits survive and reproduce more successfully.
15. evolution – When unrelated species evolve similar traits because they live in similar environments.
16. with modification – Darwin’s idea that species change over generations and share common ancestors.
18. age – The exact age of a rock, fossil, or object, usually measured in years.
20. – An organism’s ability to survive and reproduce in its environment.
21. – The study of where organisms live and how they are distributed on Earth.
22. selection – Human breeding of organisms to produce desired traits.

1. characteristics – Traits an organism develops during its lifetime that were once thought to be passed to offspring.
2. tree – A diagram showing evolutionary relationships among species.
5. – Layers of rock or soil that form over time.
6. species – Organisms that show traits of both older and newer groups of species.
7. – When two species evolve in response to changes in each other.
9. structures – Body parts with similar structures that come from a common ancestor.
10. structures – Body parts with similar functions but different evolutionary origins.
11. – The study of how embryos develop before birth or hatching.
14. radiation – The rapid evolution of many species from one common ancestor.
17. – The process by which species change over time through inherited traits.
19. age – The age of something compared to another object or event.