Part of Lesson Plan: Environmental Microbiology and development of antibiotics

Activity Overview / Details

Our class has been contacted by the County Health Department to conduct a survey of microorganisms at school.  Ask class "What types of bacteria are harmful?"  See if they can identify pathogenic microbes and what problems they cause.  Ask them "Which microbes have you been vaccinated for?"  

Additionally, this is a good time to talk about the usefulness of microbes.  Ask students "Do you know of any beneficial uses of microbes?"  Prompt them for applications in food and medicine production.  "How is yogurt made?"  Sauerkraut (Germany) and Kimchee (Korea) use cabbage and Lactobacillus acidophilus.  This bacteria breaks down some of the food and releases lactic acid which acts as a preservative preventing other microbes from growing.  It also thrives in the human vagina keeping this environment acidic.  Ask the class "What can happen when a woman takes antibiotics?"  This is how yeast infections can happen.  Other microbes can take over when the environment is no longer acidic. "How can the L. acidophilus" bacteria be re-established?"  Eat yogurt!

Humans can't live without them!  Share EO Wilson's law which stresses the importance of the living environment for our long term health.  Much of the living environment he talks about is actually the microbial environment: "If you save the living environment, then you will automatically save the physical environment too,” because in order to save the living environment, you have to save the physical environment. But if you continue to focus on just the physical environment and you take care of that only, you’re eventually going to lose both of them because the living environment is essential for human life and it’s essential for the water, the soil, and the air."

Although the microbes can’t always see them, microorganisms are present in almost all environments. Many can be grown in the laboratory on plates containing a solid, nutrient-rich medium (agar plates). After several days, a single bacterial cell grows into a population of bacterial cells that is visible to the naked eye. This population of cells is called a microbial colony. In this exercise we will test for the presence of microorganisms on our hands and on objects we are in contact with in the lab and other locations at school.