Evolution and Natural Selection

5. asexual reproduction by a separation of the body into two new bodies
6. one of two or more versions of a gene
7. the dying out of a specie
8. evidence of organisms that have existed.
11. any cell or organism that possesses a clearly defined nucleus.
14. the drifting of the frequency of an allele relative to that of the other alleles in a population over time
16. occurring without the sexual union of male and female gametes
17. the process through which populations of living organisms adapt and change.
18. the study of the formation and development of an embryo and fetus
20. a permanent change in the DNA sequence that makes up a gene

1. an extreme example of genetic drift that happens when the size of a population is severely reduced
2. the process by which a species becomes fitted to its environment
3. the influence of closely associated species on each other in their evolution.
4. the reduction in genetic variation that results when a small subset of a large population is used to establish a new colony
9. occurs when the sperm from the male parent fertilizes an egg from the female parent, producing an offspring
10. choosing parents with particular characteristics to breed together and produce offspring with more desirable characteristics
12. A person's skin color, hair color, dimples, freckles, and blood type
13. the formation of new and distinct species in the course of evolution.
15. microscopic living organisms, usually one-celled, that can be found everywhere
19. the introduction of genetic material from one population of a species to another