Natural Selection

5. inactivity resulting from a static balance between opposing forces
8. remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species
10. This type of isolation is a separation of species or populations so that they cannot interbreed and produce fertile offspring
12. ability of an organism to survive and reproduce in its environment
15. a trait that helps an organism survive and reproduce
16. large-scale evolutionary changes that take place over long periods of time
17. dealing with the geographical distribution of animals and plants
18. Natural Selection is the gradual, ____ process by which biological traits become either more or less common in a population as a function of differential reproduction of their bearers
20. form of reproductive isolation in which 2 populations have differences in courtship rituals or other types of behavior that prevent them from interbreeding
22. the perserved trace, imprint, or remains of a plant or animal
26. Process through which early prokaryotic cells are thought to have engulfed other, smaller cells and eventually incorporated them as organelles

1. type of isolation that separates populations as a result of geographic change or migration to geographically isolated places
2. The gradual changes in gene frequencies in a population due to random events
3. the accumulation of differences between groups
4. the branch of biology that studies the formation and early development of living organisms
6. a change or alteration in form or qualities
7. Process by which individuals that are better suited to their environment survive and reproduce most successfully
9. the evolution of a biological species
11. Any change across successive generations in the heritable characteristics of biological populations
13. An English naturalist who established that all species of life have descended over time from common ancestry
14. the branch of biology that deals with the structure of animals and plants
19. A ____ Tree is a chart showing evolutionary relationships as determined by phylogenic systematics
21. These types of structures do not have a common evolutionary origin but are similar in function
23. The theory that evolution occurs slowly but steadily
24. Punctuated Equilibrium is a theory of evolution holding that evolutionary change in the ____ record came in fits and starts rather than in a steady process of slow change
25. type of similar structure found in more than one species that share a common ancestor