Importance of Darwin's contribution in providing a new way to understand the structure of nature. Darwin's lack of knowledge about how variation was produced severely hindered his studies. Understand how variation is produced, why there is variation, why variation is relevant to evolution. Growth, replacement, pathology. Reproduction, production of variation that can be restructured by evolutionary processes.
Chromosomes consist of long strands of DNA that typcially code for proteins.
Amino acids attached to tRNA, then assembled into protein.