This activity is a part of the Misunderstood Microbes unit.

1. Project a series of visuals to show the variation and relative scale of microbes.

• Use the slideshow featuring electron microscope pictures of microbes found at the top of the Small, Small World article to introduce students to the small scale of microbes. Emphasize the variation in the microbes’ body forms.
• Then use the Cell Size and Scale interactive to further solidify students’ understanding of the miniscule scale at which microbes exist. Point out the cells and other structures that are present in the interactive, which students will be familiar with from the activities in the Getting Organized lesson.
• Prompt students to connect to their thinking about relative scale from the cell investigation in Activity 1.4. Ask students to discuss with a partner and then elicit their ideas via a whole-class discussion: How does this visualization relate to our cell investigation in the previous activity? (Possible responses: The different magnifications of the microscope allowed us to zoom in and out of seeing the cells, similar to this visualization.)

2. Organize students into jigsaw groups to become experts on a specific body system and how microbes help that system.

• Distribute and review the Microbes: Our Best Frenemies handout, which students will use to structure their learning throughout the Microbes In or On Humans lesson.
• Explain the purpose for reading: Learn how microbes impact specific body systems and our health.
• Arrange students into “expert” groups of four, to closely read one article about microbes and its interactions with a particular body system. Provide students in each group access to one of the following articles; the expert group will work together to complete Part A of the handout. Depending on the size of your class, there may be multiple expert groups per article.
• Armpits Are "Rain Forests" for Bacteria, Skin Map Shows (integumentary System—skin)
• Feeling Anxious? Have a Pickle (nervous / digestive Systems)
• What’s Up with the Bacteria in Your Gut? (digestive System)
• Antibiotic Found in Noses—Here’s What You Need to Know (respiratory System)
• Encourage groups to chunk the reading into sections, take turns reading those sections aloud, and stop to discuss each section and add relevant information to the handout before moving on. Model this approach as needed to prepare students.
• While the expert groups are reading, prompt students to discuss the main ideas of what they read and ensure they are successfully completing the table in Part A of the handout.
• As you circulate, press students to identify evidence in the text to support their ideas, especially about how microbes are beneficial.
• Reorganize students into jigsaw groups that have at least one expert from each article:
• Review the purpose for reading: Learn how microbes impact specific body systems and our health.
• Each group member is now an expert on a different body system and microbe and should share out to the rest of the group. The other group members will listen, ask questions, and take notes on the remaining body systems in Part A of the handout.

3. Lead a discussion to debrief students’ ideas about how microbes help the systems of the human body and address open questions on the class Know & Need to Know chart.

• Elicit and discuss students’ ideas from the previous step about how microbes are helpful to different body systems.
• Review some of the questions students generated in the Need to Know column of the class Know & Need to Know chart, which will likely include questions related to microbes’ impacts on the human body.
• Prompt students to decide if the ideas they shared from the readings help to answer some of these questions.
• Add any new questions that students have about microbes and the human body.
• Additionally, resolve any open questions in the Need to Know column that students now can answer as a result of completing the activities in the Getting Organized lesson.
• Explain that although students have some of the information to address part of the Unit Driving Question (Which microbes should we protect or eradicate to keep our bodies healthy?), they will be able to fully answer the question after the remaining two activities in the Microbes In or On Humans lesson.

4. Analyze a PSA to prepare for project work in the Misunderstood Microbes unit. 

• Remind students of the project they will undertake in this unit: Small groups will collaborate to create a public service announcement (PSA) with an online animation app (teacher’s choice) that introduces a particular microbe to their community. Their PSA will include an evidence-based argument regarding the value of eradication for the microbe based on how it impacts the systems of the human body.
• Explain that to prepare for making their own PSA, students will be watching and analyzing a variety of example PSAs throughout the Microbes In or On Humans lesson.
• Remind students that the purpose of a PSA is to inform or persuade the public and that effective PSAs use engaging visuals and text to communicate important information to the audience.
• Explain that students will critique how well this PSA conveys information and see if they can identify the target audience.
• Remind students that effective feedback is specific, helpful, and kind.
• Distribute the PSA Design Analyzer. Model for students how to use the design square to note the effectiveness of different design elements as they watch the first sample PSA. In the first design square, students should take notes about each of the following elements in the designated part of the square:
• Visuals / Animation
• Text
• Information
• Call to Action
• Show the How the Food You Eat Affects Your Gut PSA, prompting students to take notes on the first design square during and after watching.
• Ask students to share some of the effective and less-effective design elements that they noticed, either in small groups or as a whole class. (Possible responses: Students will likely point out many positive elements such as great animation and narration. Areas that could use improvement include sections with complicated information that might be hard for viewers to understand quickly. Also, while the purpose of the PSA becomes clear by the end of the video (it promotes understanding of how healthy food choices support healthy gut microbes) the key message is delayed; the call to action could be introduced much earlier.

5. Present options for the focal microbes students can select for their project work during the Introduce a Microbe to the World! lesson.

• Direct students to read the opening paragraphs about the following microbes on the CDC website:

1. E. coli (bacteria)
2. Botulism (bacteria)
3. Measles (virus)
4. Giardia (protozoan)
5. Valley Fever (fungi)
6. Ringworm (fungi)

• Ask students to rank their first, second, and third choices for which microbe they want to focus on in their projects. Explain that you will use their rankings to make project groups in the Research a Microbe and Develop an Argument About its Eradication activity. 

1. Students learn about harmful microbes from a PSA about foodborne disease that presents a case study about Escherichia coli, known as E. coli.

• Prepare students to watch the PSA by building background knowledge about E. coli. Show a picture of E. coli (See "Scanning Electron Microscope (SEM)" image in the slideshow at the top of this page) and ask what students know or can predict about this particular microbe.
• Build on students’ prior knowledge as you provide the following information about E. coli: Scientific name: Escherichia coli
• Scientific classification: Bacteria; one species that is further broken down into specific strains.
• Where it is found: Normally lives in the intestines of humans and animals and are harmless.
• Impacts on humans: Certain strains of it can make people sick.
• How transmitted: By consuming water and food contaminated by infected feces.
• Prompt students to consider the following questions as they watch the Foodborne Diseases video:
• What is the purpose of this PSA?
• Who is the intended audience?
• What is its call to action?
• Analyze the PSA and discuss the potential harm caused by E. coli microbes: discuss the following questions in a Think-Pair-Share or whole-class format:
• What is the PSA’s purpose, audience, and call to action? (Possible responses: The purpose is awareness and responsibility for prevention; intended audience is consumers; and the call to action is that understanding various factors that can lead to foodborne illness (farm, processing, transportation, vendors, consumers) helps us protect ourselves and communities.)  
• Based on what you know about bacteria and other microbes, which parts of our food system could help transmit E. coli? (Possible responses: Warm temperatures during transportation and unhygienic conditions at farms and vendors provide optimal environments for bacteria to survive and reproduce.)
• During the outbreak discussed in the PSA, lettuce, tomatoes, and sprouts were all considered possible sources. Why do you think fresh vegetables could be carriers for E. coli? (Possible responses: Vegetables that have been exposed to contaminated water or another source of E. coli need to be washed thoroughly or cooked to eradicate the bacteria; this sometimes does not happen with vegetables that are consumed raw.)
• Support students in understanding how E. coli infiltrates and impacts the human body, through the lens of body system organization discussed in the Getting Organized lesson.
• Direct students to the PSA Design Analyzer. Prompt students to use the second design square to note the effectiveness of different design elements in this PSA. Discuss as needed.

2. Students learn about specific types of microbes that have harmful impacts on the human body through a jigsaw.

Expert groups collaborate to learn about specific types of microbes that can be harmful.

• Prompt students to return to their Microbes: Our Best Frenemies handout, which students will continue to use throughout this lesson.
• Use the same jigsaw structure and groupings that you used in the Helpful Microbes activity, follow the steps below to have students engage with and share about different parts of the Infectious Agents infographic.
• Assign each expert group to one type of the following infectious agents. Depending on the number of groups, it is likely multiple groups will be assigned to the same agent.
• Bacteria
• Protozoa
• Viruses
• Fungi
• Since parasitic worms are not microbes, use this part of the infographic to model how students should make sense of the reading and transfer key ideas to Part B of the handout.  
• Provide time for expert groups to read about their assigned infectious agent.
• As you circulate to support understanding, prompt students to discuss the main ideas of what they read, define unfamiliar terms, and ensure they are focusing on how microbes are harmful to particular body systems.

Jigsaw groups share what they have learned about harmful microbes.

• Reorganize students into their jigsaw groups. Each group member is now an expert on a different type of microbe and should share out to the rest of the group. Group members should take notes on the remaining microbes listed in Part B of the handout.

3. Introduce the immune system and how it helps protect the body from infection or disease caused by microbes.

• Elicit students’ initial ideas about the immune system and how it works.
• Then show the Innate Immune System video to introduce the body’s first line of defense against microbes that cause infection or disease.
• Ask: How does the immune system help the body to protect against the type of microbe that you became an expert in?
• Then show the Adaptive Immune System video to introduce the body’s second line of defense. This is relevant for all pathogens, but will especially help students whose focal microbe was a virus.

4. Analyze two sample PSAs about microbes’ harmful impacts to help prepare students for their project work.  

• Remind students about the project they will undertake in this unit: Students collaborate in small groups to create a public service announcement (PSA) with an online animation app (teacher’s choice) to introduce a particular microbe to their community. Their PSA will include an evidence-based argument regarding the value of eradication of the microbe, based on its various impacts on the systems of the human body.
• Explain that they will watch and analyze two more sample PSAs.
• Direct students to the PSA Design Analyzer. They should use the third and fourth design
• squares to analyze the following design elements:
• Visuals / animation
• Text
• Information
• Call to action
• Show the Fight BAC (Bacteria) PSA, prompting students to take notes on the third design square during and after watching. Since this PSA is short (30 seconds), it may be helpful to show it a second time.
• Next, show the Fight the Bite: Lyme Disease PSA, prompting students to take notes on the fourth design square during and after watching.
• Encourage students to discuss the design elements that they noticed in the sample videos, either in small groups or as a whole class.

This activity is part of the Misunderstood Microbes unit.

1. Introduce the idea of eradicating microbes and consider the implications of eradication.

• Project the short article about the eradication of smallpox: This Day in Geographic History: Smallpox Eradicated. Read the article to the class; model active reading as you pause to discuss unfamiliar terms as needed.
• Lead a brief discussion about the implications of eradication. Guiding questions:
• Eradication means to totally destroy the existence of something. What else can you think of that’s been eradicated or should be eradicated? (Possible response: Other diseases (polio and rabies are considered nearly eradicated), some invasive species, students might also suggest large-scale goals, such as eradicating world hunger or poverty.)
• Why do you think scientists focused on smallpox for eradication? (Possible response: Because smallpox had a high mortality rate, it did not have a cure, and it was highly contagious.)
• Based on what you have learned about microbes in the past two activities, do you think eradication is always positive? (Possible responses: Yes, because so many microbes cause disease and infection in humans. No, because the vast majority of microbes are helpful to humans.)

2. In preparation for their project work in the Introduce a Microbe to the World! lesson, read about the connections between microbes, a disease or condition that afflicts humans, and our efforts to eradicate the microbe.

• Explain that students will work with a partner to learn about two to three diseases and microbes on The Microbiome and Disease site and take notes on Part C of the Microbes: Our Best Frenemies handout.
• Highlight how students will think about the relative need to eliminate each disease or health condition by ranking it on a scale of importance. Provide two contrasting examples for students to consider. Ask: 
• How important is it to eradicate acne for all people? 
• How important is it to eradicate cancer for all people?
• Introduce the ranking scale (critical, important, debatable, unimportant) and prompt students to articulate a reasoning statement for their eradication rankings.
• Work with the class to select or assign diseases; ensure that all 15 diseases on the list will be read by at least one partner group.

3. Create a class Microbe and Disease Eradication Spectrum for students to visualize their rankings of which diseases and microbes should be eradicated.

• Draw a spectrum on the board that reflects the importance ranking for eradication that students used for their diseases:

1. Critical         
2. Important         
3. Debatable        
4. Unimportant

• Have representatives from each partner group come up to the board and write their health condition/microbe where they think it should belong on the spectrum. For health conditions that were read about by more than one partner group, be sure they distinguish their rankings from each other.
• Elicit reasoning ideas from students for their rankings for particular health conditions/microbes, especially those with the debatable ranking. 
• As students share their reasoning, prompt them to share more about the biology of that particular microbe.
• Note that many of the readings focus on the benefits and harmful aspects of microbes. If students are having trouble determining or reaching consensus for a ranking, have them present their viewpoints to the class and lead a brief discussion to show how microbes can be both beneficial and harmful.
• Additionally, emphasize that studying microbiome and microbiology is an emerging field; press students to consider other possible uses or benefits that their microbe may have, that humans do not yet know about.
• Explain that this activity is preparing students for their project work in Introduce a Microbe to the World! lesson, during which they will decide if another type of microbe should be eradicated.

4. Show two sample PSAs related to the complications involved in trying to eradicate microbes, to help prepare students for their project work in the Misunderstood Microbes unit.  
If needed, remind students of the project they will undertake in this unit:

• Students collaborate in small groups to create a public service announcement (PSA) with an online animation app (teacher’s choice) to introduce a particular microbe to their community. Their PSA will include an evidence-based argument regarding the value of eradication of the microbe, based on its various impacts on the systems of the human body.
• Explain that they will watch and analyze two more sample PSAs.
• Direct students to the fifth and sixth design squares on the PSA Design Analyzer to analyze the following design elements:
  • Show the Antibiotic Resistance (short) PSA, prompting students to take notes on the fifth design square during and after watching.
  • Since this PSA is short (30 seconds), it may be helpful to show it a second time.
• Then show the Threat of Antibiotic Resistance (long) PSA, prompting students to take notes on the sixth design square during and after watching.
• Consider having students share out some of the design elements that they noticed in the sample videos, either in small groups or as a whole class.