Evolutionary History

4. the process by which the distribution of traits in a population changes over many generations
5. a random change to a gene that sometimes results in a new trait
7. a group of organisms of the same kind (in one or more populations) that do not reproduce with organisms from any other group
10. a specific characteristic of an individual organism
13. the very long time that spans the history of Earth, from the very first cellular life to the present
15. to classify based on scientific examination
16. having died out completely and no longer alive anywhere on Earth
18. a graph that uses bars to show how characteristics or values are distributed within a group
20. a scientist who studies fossils in order to understand the ancient history of life on Earth
22. living things, such as plants, animals, and bacteria
25. population an older population from which two or more newer species descended

1. a group of individuals born and living at about the same time
2. a more recent species that evolved from an ancestor population
3. structure a part of an organism (for example, one or more bones)
6. a group of the same type of organism living in the same area
8. everything (living and nonliving) that surrounds an organism
9. sharing a common ancestor population
11. evidence of life from the past, such as fossilized bones, footprints, or leaf prints
12. a body structure in two or more species that features the same parts (for example, the same bones)
14. a trait that makes it more likely that an individual will survive in a specific environment
17. the process by which species adapt to environmental changes over a very long time
19. to receive genes from a parent
21. an organism's arm, leg, or wing
23. the process by which one population evolves into two or more different species
24. a related organism from a previous generation
26. when something stays mostly the same over time