Evolutionary History

4. a more recent species that evolved from an ancestor population
7. an organism's arm, leg or wing
9. a scientist who studies fossils in order to understand the ancient history of life on Earth
11. when something (like a population or a trait) stays mostly the same over time
15. everything, living and nonliving that surrounds an organism
17. a random change to a gene that sometimes results in a new trait
18. the process by which one population evolves into two or more different species
19. having died out completely and no longer alive anywhere on Earth
20. to classify based on scientific examination

1. a graph that uses bars to show how traits and values are distributed in a group
2. a body structure in two or more species that features the same parts (for example, the same bones)
3. sharing a common ancestor population
5. an older population from which two or more newer species descended
6. a related organism from a previous generation
8. the process by which the distribution of traits in a population changes over many generations
10. a part of an organism (for example, bones)
12. the process by which species adapt to environmental changes over a very long time (thousands to millions of years)
13. living things, such as plants, animals and bacteria
14. the very long time that spans the history of Earth, from the very first cellular life to the present
16. evidence of life from the past, such as bones, footprints or leaf prints
18. a group of organisms of the same kind (in one or more populations) that DO NOT reproduce with organisms from any other group