Genetics and Evolution

2. A thread-like structure of nucleic acids and protein found in the nucleus.
6. Similarity in characteristics resulting from shared ancestry.
9. A trait that only appears when two copies of the gene are present.
10. One of two or more alternative forms of a gene.
11. The preserved remains or impression of a prehistoric organism.
13. An early type of animal or plant from which others have evolved.
14. The observable physical characteristics of an individual.
15. When a population is separated, often leading to the birth of a new species.
18. A genetic trait that masks its partner; the "louder" allele.
19. The evolutionary process by which new biological species arise.

1. The complete set of genetic material present in a cell or organism.
3. A "typo" in the genetic code; a change in DNA sequence.
4. The genetic makeup of an organism, as opposed to its physical appearance.
5. The offspring of two plants or animals of different species or varieties.
7. A structure that has lost all or most of its original function (like a human tailbone).
8. Darwin's "natural" process for determining survival.
11. A measure of an organism's ability to survive and provide for the next generation.
12. A unit of heredity; a segment of DNA that codes for a trait.
16. A trait that helps an organism survive and reproduce in its environment.
17. A sequence of species each of which is considered to have evolved from its predecessor.