1. Life Science Biological Evolution

2. Adaptation Any feature or behavior that enable an organism to survive and reproduce in its environment. Click here to reveal the definition!

3. Analogous Structure A physical feature possessed by a species that is similar in function to a physical feature possessed by a different species, but that is not related in development or evolutionary origin. Click here to reveal the definition!

4. Animalia A kingdom of multicellular, heterotrophic organisms, most of which can move about freely at some point in their life cycle. Click here to reveal the definition!

5. Archaebacteria A kingdom of bacteria that live totally without oxygen and produce methane; bacteria not classified as Eubacteria. Click here to reveal the definition!

6. Behavioral Adaptation An inherited behavior, such as feeding, mating, breeding, or migrating, that helps an organism to survive in its environment. Click here to reveal the definition!

7. Chemosynthesis The synthesis of organic compounds by energy derived from inorganic chemical reactions. Click here to reveal the definition!

8. Cladogram A diagram used to classify related organisms according to their primitive and derived traits. Click here to reveal the definition!

9. Complete Metamorphosis The change in body structure of some organisms from egg, larva, pupa, and adult. Click here to reveal the definition!

10. Dichotomous Key A key for identifying organisms based on a series of choices between alternative characters. Click here to reveal the definition!

11. Evolution The process by which living things change over time. Click here to reveal the definition!

12. Fitness The capacity of an organism to survive in its environment. Click here to reveal the definition!

13. Fungi The kingdom of heterotrophic organisms that decompose other organisms; yeasts are the only single-celled fungi. Click here to reveal the definition!

14. Homologous Structure A physical feature in an organism that corresponds to another feature in a different species. Click here to reveal the definition!

15. Incomplete Metamorphosis A form of metamorphosis in which the stages are egg, nymph, and adult, and lacking a pupa stage as in complete metamorphosis. Click here to reveal the definition!

16. Monera A kingdom of unicellular prokaryotes that can be either hetero- or autotrophic and that are the most abundant life forms on Earth. Click here to reveal the definition!

17. Mutation Any change in a gene; in gametes, mutations can cause a new trait to appear in an offspring. Click here to reveal the definition!

18. Natural Selection Survival of the fittest; the theory that organisms that are best adapted are the ones most likely to survive and reproduce. Click here to reveal the definition!

19. Physiological Adaptation An evolutionary adaptation that regulates a body function and that can be passed on to offspring. Click here to reveal the definition!

20. Plantae A kingdom consisting of mostly multicellular autotrophs, although some (most red, brown and green algae, for example) are single-celled. Click here to reveal the definition!

21. Population A group of individuals of the same species that occupy the same geographical area and that can interbreed. Click here to reveal the definition!

22. Protista A kingdom consisting of eukaryotic microscopic organisms; can be uni- or multicellular, and either hetero- or autotrophic. Click here to reveal the definition!

23. Species The most specific taxonomic group made up of closely related organisms that can produce offspring that, in turn, can reproduce. Click here to reveal the definition!

24. Structural Adaptation An evolutionary adaptation involving the shape of an organism; an example is the transformation of toes to hooves in horses. Click here to reveal the definition!

25. Variation Differences in inherited traits among members of the same species; variation provides the raw material for evolution. Click here to reveal the definition!

26. Vestigial Structure An unused anatomical feature, such as the human tailbone or appendix. Click here to reveal the definition!