Describe key events in the development of modern medicine. Understand virulence and how it can evolve. Apply adaptationist thinking to human health issues. Flu virus evolves a million times faster than mammals. Every year there are new strains of influenza that public officials must deal with. Officials must be able to predict these mutations in order to prepare vaccinations for the next season. Vaccines work by exposing patient to dead flue virus and immune system recognizes proteins as foreign and mounts response against/remembers it. Evolutionary biology and modern medicine were born at the same time and have grown in parallel. Proposed that contagious diseases like cholera are caused by germs. Epidemic which killed more than 500 people. Cause is unknown but linked to contaminated water. The evolution is measures in nucleotide substitutions. Flue strains accumulate nucleotide substitution in their hemma genes at a constant rate. Mutations usually happen at the antigenic sites.