1. Changes in populations
of organisms (19th Century; Charles
Darwin and Alfred Russell Wallace).
2. Traits inherited by individual
organisms (19th Century;
3. Chromosomal behavior
in cells (20th Century; Walter
Sutton, Thomas Hunt Morgan, Barbara McClintock).
4. DNA interactions
within cells (20th Century; Oswald
Avery, Barbara Hershey and others).
5. The molecular structure
of DNA (20th Century; James
Watson and Francis Crick).