Evolutionary History

3. an organism's arm, leg, or wing
4. the process by which the distribution of traits in a population changes over many generations
5. a group of organisms of the same kind (in one or more populations) that do not reproduce with organisms from any other group
8. to classify based on scientific examination
10. evidence of life from the past, such as fossilized bones, footprints, or leaf prints
14. the process by which species adapt to environmental changes over a very long time
15. a more recent species that evolved from an ancestor population
17. a specific characteristic of an individual organism
18. a trait that makes it more likely that an individual will survive in a specific environment

1. the process by which one population evolves into two or more different species
2. a scientist who studies fossils in order to understand the ancient history of life on Earth
6. an older population from which two or more newer species descended
7. having died out completely and no longer alive anywhere on Earth
9. a body structure in two or more species that features the same parts (for example, the same bones)
11. when something stays mostly the same over time
12. a related organism from a previous generation
13. a part of an organism (for example, one or more bones)
16. a group of individuals born and living at about the same time