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Evolution Vocabulary Definitions
1. Evolution
change in a kind of organism over time; process by which modern organisms have
descended from ancient organisms
2. Species
group of similar organisms that can breed and produce fertile offspring
3. Population
group of individuals of the same species that live in the same area
4. Speciation
formation of new species
5. Hypothesis
possible explanation for a set of observations or possible answer to a scientific question
6. Theory
well-tested explanation that unifies a broad range of observations
7. Struggle for existence
competition among members of a species for food, living space, and the other necessities of
life
8. Survival of the fittest
process by which individuals that are better suited to their environment survive and
reproduce most successfully; also called natural selection
9. Predator-prey relationship
mechanism of population control in which a population is regulated by predation
10. Fitness
ability of an organism to survive and reproduce in its environment
11. Habitat
the area where an organism lives, including the biotic and abiotic factors that affect it
12. Descent with modification
principle that each living species has descended, with changes, from other species over time
13. Common descent
principle that all living things have a common ancestor
14. Artificial Selection
selection by humans for breeding of useful traits from the natural variation among different
organisms
15. Natural Selection
process by which individuals that are better suited to their environment survive and
reproduce most successfully; also called survival of the fittest
16. Extinct
term used to refer to a species that has died out
17. Adaptation
inherited characteristic that increases an organism's chance of survival
18. Phylogeny
the study of evolutionary relationships among organisms
19. Embryo
organism in its early stage of development
20. Fossil
preserved remains or evidence of an ancient organism
21. Geologic Time Scale
scale used by paleontologists to represent evolutionary time
22. Homologous Structures
structures that have different mature forms in different organisms but develop from the
same embryonic tissues
23. Vestigial Organs
organ that serves no useful function in an organism
24. Reproductive Isolation
separation of species or populations so that they cannot interbreed and produce fertile
offspring
25. Behavioral Isolation
form of reproductive isolation in which two populations have differences in courtship rituals
or other types of behavior that prevent them from interbreeding
26. Geographic Isolation
form of reproductive isolation in which two populations are separated physically by
geographic barriers such as rivers, mountains, or stretches of water
27. Temporal Isolation
form of reproductive isolation in which two populations reproduce at different times
28. Gene Pool
combined genetic information of all the members of a particular population
29. Genetic Drift
random change in allele frequencies that occurs in small populations
30. Hardy-Weinberg principle
principle that allele frequencies in a population will remain constant unless one or more
factors cause the frequencies to change