Microbes Rule!

Rationale

In the past I have treated chemistry as a separate science and did not try to incorporate any biological concepts. I am learning to see the value in combining content areas rather than segregating them. Since students in Pennsylvania now have to pass the Keystone Biology test in order to graduate from high school, it has become overwhelmingly clear that I need to use biological examples as much as possible in my chemistry classes. If students do not pass this standardized test in their 9th grade year, then they have to keep taking it twice a year until they do pass. If they did not comprehend biology content while enrolled in the course, then they need every bit of reinforcement that I can offer them. This unit will combine the mechanisms of chemical reactions with the interactions of microbes to see how the two work together to make us who we are. Students will be fascinated to learn about how many microbes are in us and around us without knowing it.

There is an idea called the hygiene hypothesis which seeks to explain why our overly clean modern living environments actually cause us to be less healthy. Essentially, this hypothesis states that the absence of certain infections during our childhood causes our immune systems to become confused, and to turn against us to produce autoimmune diseases. This idea is supported by scientific studies showing a correlation between clean living environments and increased rates of autoimmune diseases, such as asthma and other allergies. In an article written by Robin Anne Smith called "The Worms Within" she quotes Dr. William Parker and his research connecting modern living with our healthy immune systems. ¹This article suggests that our evolutionary history has played host to many wormy guests. These pathogens include hookworms, roundworms, and whipworms. ² They have made their homes in our intestines and have always had a constant supply of food and nutrients. In the developed world these pathogens seem to be lacking but one third of the worlds' population is still infected with these intestinal worms. ³Many intestinal parasites are passed from person to person when tiny amounts of feces get on our fingers or when we walk barefoot on contaminated soil. ⁴ Less than 100 years ago our grandparents were introduced to indoor plumbing, this and water treatment plants have played a major role in the reduction of our exposure to parasitic worms. The parasites that make our gut their home are also known as "helminthes" according to Parker. ⁵Throughout our evolution we coexisted with our parasites. According to Dr. Janette Bradley these adaptations have left a mark on how our immune system is structured and controlled. Bradley also suggested that the reason our immune system overreacts is because when we live in an ultraclean environment without worms it doesn't have enough to do. ⁶ This shows that our immune system needs the chemicals that are produced by the helminthes naturally. Our bodies have evolved to rely on these parasites just as they rely on us. This becomes a problem because they are able to evolve at a much faster rate than we can. ⁷

Students always want to know why they have to take chemistry and why they need to know the content. By using examples that are relevant to them, I hope they will see the importance of understanding the science involved in making us who we are. Every single student at least knows someone who suffers from allergies and/or asthma even if it doesn't affect them personally. I would like to connect the chemistry and biology by analyzing the law of conservation of matter and how in every chemical reaction atoms are just rearranged, never created or destroyed. I would like students to look at the environment they live in and describe how it compares to the environment that was present thousands of years ago. They will look at the prevalence of asthma and allergies and determine what some of the causes of the changes could have been. According to Kathleen Barnes there are two sides of the immune system. The Th1 side deals with bacteria and viruses, and the Th2 side deals with worms. ⁸Dr. Barnes believes that trying to figure out what the helminth-made proteins do inside of our bodies will be incredibly difficult to replicate as a drug. ⁹