1. Viruses!!!
Incredibly small! Obligate intracellular parasites; have a “host range” “lock-and-key” fit between proteins on outside of virus and receptors on host cell; some viruses have wide range (like West Nile); others like measles / polio very narrow; many infect only certain types of cells

2. Viral Life Cycle: The Lytic Cycle
Culminates in death of the host cell; virulent phage; but bacteria have restriction enzymes for defense!

3. Viral Life Cycle: The Lysogenic Cycle

4. Animal Viruses: HIV
Culminates in death of the host cell; virulent phage; but bacteria have restriction enzymes for defense!

5. The raw material for evolution is….

6. Sources of Genetic Variation?

7. Bacterial Reproduction

8. Other Sources of Genetic Variation in Bacteria:

9. Transposable Elements