Unit 7

3. variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.
6. the process through which populations of living organisms adapt and change
9. the total genetic diversity found within a population or a species.
11. Structures that have no apparent function and appear to be residual parts from a past ancestor are called
13. a type of reproductive isolation mechanism among sexual organisms in which the differences in the timing of critical reproductive events prevent members of closely related species
16. the identification by humans of desirable traits in plants and animals, and the steps taken to enhance and perpetuate those traits in future generations.
18. natural phenomenon used by plants and animals to blend into their environment
19. any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences
20. how a new kind of plant or animal species is created.
21. the variety of life on Earth at all its levels

1. pertains to the state or quality of being fit, e.g. physically or mentally, as in physical fitness
2. the reduced genetic diversity which results when a population is descended from a small number of colonizing ancestors.
4. the study of the formation and development of an embryo and fetus
5. similar physical features in organisms that share a common ancestor
7. the process by which a species becomes fitted to its environment; it is the result of natural selection's acting
8. The physical separation of members of a population
10. all the inhabitants of a particular town, area, or country.
12. when a population is greatly reduced in size.
14. the superficial resemblance of two or more organisms that are not closely related taxonomically
15. represents the incidence of a gene variant in a population. Alleles are variant forms of a gene that are located at the same position
17. the hypothesis that evolution proceeds chiefly by the accumulation of gradual changes (in contrast to the punctuationist model)