Microbes Rule!

Strategies and Activities

The strategies presented are designed to help students practice using models and interact with text to access the extensive amount of information required by the AP Biology curriculum. My goal is that by delivering lessons in this manner, students will not only build these skills, but will interact with the content in a way that will help cultivate the curiosity that will propel them through the unit. In doing so, students will look to use the concepts they are learning to make connections with the big picture ideas and ask the questions that are relevant in society today.

Activity One: Introduction and Immune System

The unit will begin with students activating prior knowledge by looking at a Wordle (see Appendix B) and self-assessing which words they are strongly familiar, somewhat familiar, and unfamiliar. In addition to students being able to access prior knowledge and identify concepts that may prove to be more of a challenge, this will give students the opportunity to preview vocabulary for the unit. Students should also predict the important topics and concepts that will be pertinent to the unit.

Once students have previewed the unit, they should move into the immune system. Since the end goal is for students to make connections between the coevolution of pathogens and their hosts, as well as understanding why HIV vaccines have been so evasive to the scientific community, they will need to have an underlying comprehension of how our immune systems work to protect us against disease. It is likely that, in my classes, some students will have heard the word innate before. After defining the term as a class, it will be applied to immunity and students will brainstorm parts in the human body that make up the innate immune system. I predict that, as a class, students will be able to come up with things like the skin, mucosal membranes, and cilia. It is also likely that they will need to be introduced to terms like macrophages, MHCs, and the immune response. A variety of animations and videos are available online to help students visualize these processes. After being introduced to these concepts, students will be asked to create their own models or outlines of the innate immune system and immune response.

A similar protocol will be used to introduce the idea of acquired immunity. It is pertinent that students have a strong understanding of the humoral acquired immunity since it is the T helper cells that are directly invaded by HIV. To foster student's understanding of immunity, students will complete a POGIL ^TM activity from the POGIL ^TM: Activities for AP* Biology. This resource is available through Flinn Scientific and presents models to students for analysis. The immunity activity uses models to introduce both cell-mediated and humoral acquired immunity. The process is designed so that students work in groups to investigate models. At important intersections, we stop as a class to discuss the material. Particularly important is investigating the questions that emphasize key ideas or higher-level questions. Even with straightforward questions, there are times when the phrasing and vocabulary involved make them difficult for students to access. One protocol we have used in class is to ask students to write out all sub-questions required to answer the question presented. This requires students to create their own scaffolding and build the metacognitive skills required to break down questions and, thus, answer higher-level questions. Upon discussing humoral immunity, I will ask the students the follow up question: "What is the significance of antibody specificity?" It is likely that students will struggle with this question and will need to use the same protocol to decode the question. Questions similar to this one will also help students contrast innate and acquired immunity, which can also be referred to as nonspecific and specific. We will not complete the extension questions of this activity since these concepts will be introduced through the next activity. Upon completion of the POGIL ^TM, students will create a graphic organizer with vocabulary and phrases to help them organize important information. The students should be able to complete the graphic organizer outside of class, but it is recommended that they brainstorm with peers the important topics and contents that should be included.

These activities should take approximately three days but students should have a sound understanding of the processes of innate and acquired immunity. They should be able to contrast the types of immunity and differentiate between cell-mediated and humoral acquired immunity. Students should be able to use vocabulary, such as cell types and their roles, while explaining these processes and identifying the significance of pathogen specificity in acquired immunity. Finally, students should relate pathogen specificity and immune memory to articulate why secondary infections result in rapid and heightened immune responses.

Activity Two: Viruses and their Evolutionary Role

After learning about the immune system, students will be in a place to understand how vaccines manipulate the immune system into protecting a person against a particular pathogen. Since smallpox and HIV will be used as a paradigm to teach the history and functionality of vaccines, I intend to first help students develop stronger understandings of viruses. The first part of this activity will involve students identifying similarities and differences between various viruses that are illustrated in their textbook. The viruses included are: Adenovirus, a bacteriophage, Tobacco Mosaic Virus, and Influenza Virus. These viruses are an excellent sample because they show variety in genetic material, presence of an envelope, viral structure, and include bacteriophages that infect bacteria. By comparing these models, students should be able to identify that viruses all have a genetic material and capsid. This, in general, defines viruses. Viruses are, however, able to infect different cell types, contain different types of genetic material, and can have very different structures, including the presence of a viral envelope. Students will have previously been asked to read the forward and introduction from Carl Zimmer's A Planet of Viruses. Students will be asked what stuck out to them about the reading and how it relates to what we are studying. After a short discussion, we will also look at the images found in the textbook that illustrate the viral life cycle. Students will be asked to write a description of viral life cycles with a partner, being sure to compare and contrast the lytic and lysogenic life cycles of viruses. As part of a whole class discussion, I will ask students which type of a life cycle is more destructive. I predict that most students will identify the lytic life cycle as more destructive. As a follow up question, I will also ask students how the lysogenic cycle of a virus, or any latent stage of an animal virus, could potentially be more destructive to a species? My goal in this exercise is to get students thinking about the infectious aspect of viruses and how latent phases of viruses can actually increase the spread of an infectious disease.

I also want students to have an opportunity to learn more about a variety of viruses while gaining deeper knowledge about the classifications and specifics of viral structure and life cycles. To cultivate this curiosity and foster discovery, I will assign all students to read the Endogenous Retroviruses chapter of A Planet of Viruses while also allowing them to choose an additional chapter from a selection about other viruses including: Rhinovirus ("The Uncommon Cold"), Influenza ("Looking Down from the Stars"), Papillomavirus ("Rabbits with Horns"), Bacteriophages ("The Enemy of our Enemy"), marine phages ("Oceans of Viruses"), West Nile ("Becoming an American"), or SARS and Ebola ("Predicting the Next Plague"). In small groups, students will have to share the type of virus they read about, how it connected to what we've been learning, any hints as to what type of life cycle it has, and any additional information that was of interest. They will also have to discuss why I thought it was important that all students read about Endogenous Retroviruses and identify the main ideas of the chapter. My goal is that students will practice using vocabulary to discuss their reading while also practicing comprehension skills and making connections to the content. Not only will this help facilitate literacy skills, but it will introduce them to a variety of fascinating information and imagery that should propel them through some of the more conceptual topics. Another goal of integrating these readings is that they show the versatility of viruses and begin to touch upon their role in our history as a species. It will also get students thinking about how these viruses will also play a role in our future. Upon completing the partner discussions, we will do a share out with the entire class to verify that all students are on the same page about viruses so far.

The next part of this activity is centered around an additional reading. Students will read pages 15-18 and 31-32 of the article "Role of Viruses on Human Evolution" by Linda M. Van Blerkom. These reading sections include much of the Introduction and Discussion sections of the text. While reading, students will be asked to identify: clarifying questions, main ideas, and points of interest. Once groups have concluded compiling their information, they will be asked to share with one another on posters through the room. This will help students visualize information and guide a group discussion. Students should also be able to make connections to the chapter on Endogenous Retroviruses that they all read from A Planet of Viruses in addition to information from their selected chapter to help them explain the role that viruses and humans play in the evolution of the other. As a facilitator in the classroom, I will be sure to make sure that the discussion defines the concept "pathogen-host arms race" as is referenced in both readings. Upon completion of the activity, students should be able to explain what all viruses have in common while also indicating the differences that can be found within the objects. Within this three-day lesson cycle, students should be able to articulate the life cycles of viruses, including lytic and lysogenic stages, and should indicate how these life cycles can impact the pathogen. They should also be able to articulate the impact of latency on the ability of a virus to "survive." Finally, students should be able to explain how the relationship between pathogen and host results in a continuous evolution of each.

Activity Three: Vaccines

Once students have had an opportunity to investigate viruses in more detail, they are ready to go back and make the connection between the pathogen and immune system. The development and mechanism of vaccines is a great way to tie these concepts together. As the first vaccine and the only virus to be eradicated from the planet, smallpox is an excellent paradigm through which to teach students vaccines. I intend to begin this discussion with having half of my class read "Edward Jenner and the history of smallpox and vaccination" by Stefan Riedal and the other half read the chapter on smallpox, "The Long Goodbye," from A Planet of Viruses. These articles look at the history of smallpox and the creation of vaccines from two different lenses, while still emphasizing the process of vaccine development and the role they have played in our history.

To facilitate a discussion, I intend to use a fishbowl protocol that has been tweaked by faculty at my school to integrate technology and increase engagement. As per a normal fishbowl activity, half of the class will begin in the inner circle, with the other half of the class seated in a circle surrounding their peers. The "inner circle," however, will actually have two tables that face each other. One table will include students that read the article, while the other table will seat students that read the chapter. These students will be asked to share with each other the main ideas and supporting details that were presented in each of their readings. They may also share concepts that students felt were important or interesting. In fact, each article contains its own commentary on social or ethical interests, which will likely draw in students during reading. I expect that these commentaries will also help liven discussion. The students on the outside of this circle, will be able to use computers or their cell phones to access a program or website, such as Todays Meet ^© at www.todaysmeet.com. This website allows you to create a room for your class in which students are able to enter their own name and submit comments in real time. By connecting a computer displaying the site to a projector, the students on the outer circle will be able to silently participate in the discussion by adding their own comments or reactions to the discussion. At this time in the school year, students will have already participated in enough discussions that they will know the classroom norms. Still, we will review them prior to beginning the discussion. Additionally, students will be reminded how they get credit for participation in a discussion. This will include participating at least once in which they directly reference a page or quote in the text and explain the significance of that selection. They will also have to react to another student's comment and will receive credit for following norms.

Once students have had time to participate, I will request that the inner and outer circles exchange places. The inner circle will then be expected to discuss the crosscutting concepts that they heard based on the discussion of the previous group. They will also be asked to identify implications of the content discussed from the readings. Again, students in the outer circle will be able to participate in this discussion by adding their thoughts or reactions to Todays Meet ^©, which will be projected on the board. This type of facilitation enables students to interact with each other, even if they are not all part of the inner circle. In the case that a student has high anxiety in participating in front of the class, students can also get credit for their Todays Meet ^© contributions and/or by posting a reflection and reaction to the class webpage. Upon completion of this discussion, we will end the class by connecting this information to how vaccines work. Students will be asked to answer the question "How do the mammalian immune system and the structure of viruses explain the use of vaccines?" Students may need time to talk through their thoughts with a partner before settling on an agreement as a large class. Optimally, this activity will take two days to complete with the intended outcome being that students are able to answer the aforementioned question by linking the structure of viruses and the mechanisms of mammalian immune systems.

Activity Four: Understanding HIV

Before students will be ready to have academic conversations about the struggle to develop vaccines for HIV and theorize what can be done to solve this problem, they need to have a strong background knowledge on the structure and life cycle of HIV, as well as why it is such an area for concern of the human species. Students will begin their introduction by reading the chapter on HIV in A Planet of Viruses, entitled "The Young Scourge." This chapter provides a very basic overview of the virus, the impact it has had on the human population around the world, its origin, and a brief description of how it infects cells. After students read the chapter, they will have a chance to share their reflection of the reading, but this will be brief.

They will then spend approximately three days on an activity that I will modify from the National Center for Case Study Teaching in Science created at the University of Buffalo. This particular activity, entitled "Resistance is Futile—Or is it?: The Immunity System and HIV Infection," is written by Annie Prud'homme-Genereux from Quest University in Canada and is available online (see Appendix B). In Part I, I do not intend to give my students the diagram of HIV infection but, instead, will change question 1c to require students to diagram this process on their own. Additionally, I will ask my students why the illustrators chose to use a key to represent gp120. This will help students develop a stronger understanding of the role of this protein but will also remind them of the intentionality of model design. I do not plan to spend much time reviewing the immune system, as we will have covered this in depth, so I do not plan on asking my students to complete any of question 2. I will also remove part of question 3 and all of question 4. For time's sake, I do not intend to ask students the questions that pertain to Part II, but will use it as an introduction to the next section. The reason I am particularly excited about the remainder of this activity is because it requires students to use their science skills to understand immunological advantages that some individuals have against HIV. It uses actual data from research studies and has students interpret the methodologies, make predictions, and interpret results. All of these methods build science skills while also preparing students to interpret more in-depth scientific papers that they may encounter later in life. Students should complete this activity with a thorough understanding of the structure of HIV and impact that it has on the human immune system. They should be able to use both of these concepts to explain why some individuals have observed immunity or stronger defenses against HIV infection and, thus, AIDS contraction.

While the case study will provide students with a detailed understanding of genetic mutations that provide advantages to certain individuals, I want to make sure that my students are also able to discuss the various aspects of HIV that make it so evasive to scientists who are trying to create vaccines for the general public. The students will participate in a jigsaw reading activity with their lab groups. This will also require students to dive into a vocabulary heavy research study and identify main ideas of certain sections. Different groups will receive a section from "Implications of Recombination on HIV diversity" by Ramirez et al. Each group will be assigned one of the following sections to read and interpret: Introduction (Section 1), Recombination in HIV: requirements and mechanistic outputs (Section 2), HIV Classification and Figure 2 Interpretation (Section 3.1), Recombinant forms in the epidemics & Limits to recombination (Sections 3.2 & 3.3), and Recombination, the host, and antiviral treatments (Introduction to Section 5). The level of reading in this article will be extremely challenging for students. They will be asked to work in groups to grasp the main idea without worrying about the specific details. Once all groups have shared the main idea of their reading with the entire class, I will ask the class to answer the following questions:

• "What factors allow HIV to evade the immune system?"
• "How do these attributes make it difficult to create a vaccine?"
• "How do the mechanisms described relate to evolution as a driving force?"
• What implication might the geographic distribution of HIV genetic forms have on vaccine development?

This cycle should take approximately 5 days to complete but will thoroughly prepare students to discuss why it has been so difficult for scientists to create a vaccine to prevent the spread of HIV. They should be able to create a model of an HIV vaccine and its infection of human immune cells, articulate all of the ways that HIV is able to evade the immune system, and describe the ways in which some people have increased defense or even immunity against HIV.

Activity Five: Culminating Socratic Seminar

The culminating activity of this unit will be a Socratic seminar in which students will revisit all essential questions and will formulate all concepts learned throughout the unit to draw some relevant conclusions about HIV and vaccines. Before students participate in the seminar, they will be given one of two readings. The readings include an NBC News article written by Dr. Anthony Fauci entitled "Fauci: Why there is no AIDS vaccine" and a reading from the resource library of the Understanding Evolution website created by the University of California's Museum of Paleontology entitled "A chink in HIV's evolutionary armor." Both of these articles have different approaches to the progress made and challenges faced by scientists trying to develop an HIV vaccine. Students will be required to write a brief summary of the article in preparation for the discussion and will need to write out talking points for each of the essential questions of the unit.

In the true sense of a Socratic seminar, it will be the responsibility of students to lead the discussion, incorporate the readings, and refer to concepts that were learned. My goal is to encourage them to use all of the resources they accessed to learn the concepts in their discussions about background and next steps. To stimulate the conversation, I will also ask extension questions or provide prompted reminders to students at advantageous times. For example, I will remind them about the reference in A Planet of Viruses to the Merck vaccine that was developed and abandoned. If students do not remember this, they will have access to the text to look it up. I will also ask them if, based on what they learned about more virulent diseases like Ebola hemorrhagic fever, whether it would be ethically acceptable to genetically modify HIV so that it would become more virulent? A prompt like this will require students to activate their understanding of the concepts that apply and make connections between multiple activities. It is likely that a Seminar such as this one will not find resolution. However, before the class ends, I will present them with the news article from Huffington Post released in September, 2013 entitled "HIV Vaccine: Western University Researchers Report Success in Trials." If time remains in class, students will have a chance to reflect on the article. Otherwise, I will encourage students to react to the article on our class webpage. My hope is that by ending the unit in this manner, students will have an opportunity to demonstrate their full understanding of the content learned but will also become more active citizens by engaging in discussions around a very real, and relevant, concern in the scientific community.