Across
- 1. Process by which two species evolve in response to changes in each other.
- 4. Combined genetic information of all the members of a particular population.
- 8. Separation of a species or population so that they no longer interbreed and evolve into two separate species.
- 11. How well an organism can survive and reproduce in its environment.
- 12. A term that typically describes a species that no longer has any known living individuals.
- 14. Traits controlled by two or more genes and therefore has more than two phenotypes.
- 16. Form of natural selection in which the entire curve shifts to the left or right; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve.
- 19. A change in a species over time.
- 21. Principle that allele frequencies in a population will remain constant unless one or more factors cause the frequencies to change.
- 22. Information about past life, including the structure of organisms, what they ate, what ate them, in what environment they lived, and the order in which they lived.
- 23. A characteristic that improves an individual's ability to survive and reproduce in a particular environment.
- 25. A change in the allele frequency of a population as a result of chance events rather than natural selection.
- 27. Form of reproductive isolation in which two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of water.
- 31. Breeding organisms with specific traits in order to produce offspring with desired traits.
- 32. Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock; does not give the exact age of the fossil.
- 33. Differences between members of the same species, such as different eye colors, different height, etc.
- 34. Form of reproductive isolation in which two populations reproduce at different times.
- 35. A technique used to determine the actual age of a fossil on the basis of the amount of a radioactive element it contains.
Down
- 2. Process by which individuals that are better suited to their environment survive and reproduce most successfully.
- 3. Form of natural selection in which the center of the curve remains in its current position, but the curve gets "taller"; occurs when individuals near the center of a distribution curve have higher fitness than individuals at either end.
- 5. A book by Darwin published in 1859 that proposed the mechanism for evolution that he called natural selection.
- 6. Situation in which allele frequencies in a population remain the same.
- 7. Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change.
- 9. A biologist who developed the theory of evolution of species. He argued that all living species evolved into their present form through the ability to adapt in a struggle for survival.
- 10. An organ that has no apparent function but resembles a structure of an ancestor.
- 13. Process by which unrelated organisms independently evolve similarities when adapting to similar environments.
- 15. Random effect that can occur when a small population settles in an area separated from the rest of the population and produces offspring that have new and unique allelic variations.
- 17. Best adapted individuals survive and adapted genes get passed to offspring.
- 18. Form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle.
- 20. Presented first theory of evolution in 1809 and believed that traits acquired or lost during the life of the organism could be passed down to the offspring.
- 24. Trait controlled by a single gene that has two alleles and therefore has two phenotypes.
- 26. Form of reproductive isolation in which two populations have differences in courtship rituals or other types of behavior that prevent them from interbreeding.
- 27. Earth's history organized into four eras: Precambrian, Paleozoic, Mesozoic, and Cenozoic.
- 28. An evolutionary pattern in which many species evolve from a single ancestral species.
- 29. Similar structures that related species have inherited from a common ancestor.
- 30. Formation of new species.