Evidence for Evolution

• When did brachiopods first appear in rocks?

  500 million years ago
• How does natural selection explain pesticide resistance?

  Resistance occurs when individuals with advantageous traits survive and reproduce
• What are vital proteins found in all living things?

  DNA polymerase and RNA polymerase
• Why is Clostridium difficile not a problem for healthy people?

  Healthy gut bacteria keep it in check
• How can antibiotics affect Clostridium difficile?

  They can kill off helpful gut bacteria, allowing it to survive and reproduce