Evolution and Natural Selection

4. The reproduction of viruses using a host cell to manufacture more viruses; the viruses then burst out of the cell.
6. A branch of science that is related to the formation, growth, and development of embryos.
9. The process through which populations of living organisms adapt and change.
11. Cell type that does contain a nucleus and most other membrane-bound organelles.
13. The biological mechanism by which organisms adjust to new environments or to changes in their current environments.
14. Different organisms vary in how they look and function because they have different inherited information.
15. The complete disappearance of a species from Earth.
17. Asexual reproduction by a separation of the body into two new bodies.
19. One parent copies itself to form a genetically identical offspring.
20. Cell type that does not contain a nucleus and most other membrane-bound organelles.

1. An organism combines the genetic information from each of its parents and is genetically unique.
2. A type of structural modification made to a part of the body.
3. The reduction in genomic variability that occurs when a small group of individuals becomes separated from a larger population.
5. Something an animal does usually in response to some type of external stimulus in order to survive.
7. A large group of single-cell microorganisms.
8. When germs like bacteria and fungi develop the ability to defeat the drugs designed to kill them.
10. The change in frequency of an existing gene variant in the population due to random chance.
12. A permanent change in the DNA sequence that makes up a gene.
16. When a group within a species separates from other members of its species and develops its own unique characteristics.
18. A term that describes mechanisms of gene transfer from one population to another.