1. Population Genetics Hardy-Weinberg Equilibrium Principle An Introduction

2. All Populations Can Evolve! How many of you remember having a bacterial infection, receiving one antibiotic, and when that one didn’t work, you were prescribed a different antibiotic? Why do you suppose this happened?

3. Antibiotic Resistance and Evolution Genetics plays an increasingly important role in evolution Mutations (errors in DNA replication) alter the genetic code within each organism These mutations cause genetic change or variation Mutations can be bad, neutral, or good Evolution relies entirely on good mutations Nature selects good mutations, genetic change occurs, and ultimately new organisms are produced

4. Antibiotic Resistance and Evolution How does this apply to antibiotic resistance? First, antibiotics are substances that are naturally produced by certain microorganisms (fungi) that are used to kill bacteria. Any population of organisms includes variants with unusual traits, even among bacteria. Some bacteria have the trait to withstand an antibiotic’s attack on itself. The drug kills the weak bacteria, leaving behind or selecting those that can resist it. The bacteria then multiply, increasing a million-fold in one day! Always use antibiotics properly and according to doctors’ instructions!!!

5. Vocabulary Evolution…..genetic changes in a population How do we know genetic changes are happening? Look for change in gene frequency. Population…..all members of a species in a certain area Species…..a group of organisms that can interbreed among themselves and are fertile