Section 2: Resources

Reinforcement Activity

The Good, The Bad, and The Ugly: The Many Sides of Bacteria

Most students think of germs, microbes, and bacteria as bad and harmful. They generally have no idea of the beneficial aspects of microbes.⁴ This activity aims to help students recognize that bacteria have many good functions, such as helping to recycle nutrients for plants, helping to make cheese and yogurt, and helping humans digest food, but that bacteria also have some not-so-good functions, such as causing illnesses. After learning about how bacteria are microscopic, living things that act as decomposers, ask your students to think about what they know about living things and what they need to survive. Ask them to think about some of the needs of bacteria. Tell the students that like other living things, bacteria need food, water (or moisture) and a suitable environment in which to thrive. A suitable condition for bacterial growth is typically a moist, warm and dark environment. Explain to students that bacteria cause illnesses such as Strep Throat, tooth decay and food poisoning. Knowing what they do about bacteria growth, have your students brainstorm about ways that people can prevent bad bacteria from causing illness.

Next, discuss the ways in which bacteria are helpful, reviewing their role in decomposition of waste and recycling of nutrients, and introducing students to the idea that bacteria exist in some foods and in the stomachs of humans and many animals. It is bacteria that break down the sugars and make acids that give yogurt its tangy flavor. Many cheeses are made using bacteria. Bacteria also live in the stomachs of humans, cows, and other animals, where they help to break down food that the stomachs cannot digest on their own. Intestinal bacteria also provide many animals with essential vitamins.