Evolution

6. Process by which evolution occurs: Natural _______
7. Principle that states that living species are descended from ancient ones: decent with _______.
9. Required for natural selection to act upon
10. Proposed the theory of evolution by natural selection
11. Natural selection is also known as survival of the _______
13. Process by which unrelated organisms independently evolve similarities when adapting to similar environments (e.g. sharks and dolphin fins)
15. Well supported testable explanation
17. Structures that have no current function
20. Structures in different species that are similar because they share a common ancestor but may have different functions
21. Similarities in functions among unrelated species that result from convergent evolution - differ structurally
23. Comparison that looks at the nucleotide sequence (AGCT) to determine what organisms share a common ancestor
25. Required for new species to form. Reproductive ________.

1. When organisms disappear from the Earth.
2. The name of the ship that Darwin traveled on.
3. Pattern of evolution where a species is stable for a long time then rapidly changes
4. Formation of a new species.
5. Determining the age of fossils by measuring rates of decay of radioactive isotopes.
8. A characteristic that helps an organism survive.
12. Had different shaped beaks depending on the island they were from
14. Determining the age of a fossil by comparing its placement with that of fossils in other layers of rock
16. When one species evolves into many: adaptive _________.
18. Genetic changes over a long period of time
19. Preserved remains of ancient organisms
22. Islands that Darwin visited
24. Embryos of closely related organisms share many similar structures