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Stage 1
Identify Desired Results

Catchy Title: Evolving Resistance
Theme/Topic of Lesson: Antibiotic overuse and the evolution of antibiotic resistance in bacteria
Time Commitment: 3-5 45 minute periods
Subject Area(s):
    Science - Biology
Grade Level(s): 6,7,8,9,10,11,12
Standards Alignment:
Class Challenge Question:

How do bacteria resistant to antibiotics evolve? Why is this of concern?


In this lesson students will examine the development of antibiotic resistant bacteria from an evolutionary perspective, discover the potential causes and dangers of antibiotic resistance, and suggest possible solutions to the problem.  This topic is being hotly debated in the news as drug resistant infections  and  antimicrobial household products become more common. Students will first explore the drug resistant strain of tuberculosis which has become common in Russian prisons and explain how the bacteria evolve resistance. They will then learn about antimicrobial household products, readily given antibiotic prescriptions, and subtherapeutic levels of antibiotics in animal feed (antibiotics are put in the feed to prevent, not to treat, diseases). They will analyze these with respect to the evolutionary pressures they put on bacteria to become antibiotic resistant.

Please note: This lesson presents some either/or options. There are many attached documents to support the choices. This is not meant to be overwhelming, but rather to provide options so you can choose what will work best for your students.

Stage 2
Determine Acceptable Evidence

Learning Objectives:

The Students will:
  • explain how resistance to antibiotics may develop if the course of the medication is not completed.

  • describe how antibiotic resistant organisms are selected for in various environments

  • give specific examples from animal feed, household products, and/or medications of situations which could lead to the development and proliferation of antibiotic resistant organisms

  • explain why the development and proliferation of antibiotic resistant organisms is cause for concern

  • list ways in which individuals can help slow the proliferation of antibiotic resistant organisms


Students will be responsible for completing a number of worksheets within the lesson. At the end of the lesson, the students will be responsible for making a public health plan in which they outline one way in which the spread of antibiotic resistant organisms can be controlled and detail why it would be effective. Alternatively they are responsible for making a poster or other type of presentation to educate the audience about one of the aspects of antibiotic/antibacterial use. The poster/presentation can be neutral or take a position on that aspect of antibiotic/antibacterial use.

Stage 3
Plan Learning Experiences


Video(s)Why does Evolution Matter Now

This PBS short video shows how antibiotic resistant bacteria have evolved in Russia's prisons.
Internet SitesThe Danger of Antibiotic Overuse

This article explains why it is dangerous to demand antibiotics to treat many common ailments. You have to allow pop-ups to view this site.
CDC expands campaign against overuse of antibiotics

 This is a CNN article about stopping overuse of antibiotics in medical practices. Click on "fighting the superbug" for a cartoon about the evolution of antibiotic resistance, good to use in the first part of the lesson, or as review at the end.
Using Antibiotics Sensibly

This article from the website of the Mayo Clinic explains the uses and abuses of antibiotics in human medicine.
From bacteria to parasites: understanding the germs that cause infection

An excellent reference article on the various types of microorganisms and what they do that helps and harms us.
Study washes away antibacterial soap claims

 This is an article which reports on a study by the NIH comparing antibacterial soap to regular soap.
FDA advisors say...

 This article reports on an FDA study which compared antibacterial and regular soaps.
Antibacterial Cleaning Products and Drug Resistance

This is an article which reports the findings of a CDC study about use of antibacterials
Antibacterial products play an Invaluable Role

An article from the soap and detergent association
Alliance for the Prudent Use of Antibiotics

An excellent general resource about antibiotic resistance.Good for general background for teachers, or to learn more.
Concerns about Household Use of Antibacterial Soaps

An article about FDA concerns, with a short quote from the soap and detergent association.
Battle of the Bugs

FDA article on fighting over prescription of antibiotics. Slightly more difficult reading level.
Abuse of Antibiotics at Factory Farms

An article from the Sierra Club about abuse of antibiotics on farms.
WHO: Farmers should cut antibiotic use

From the National Cattleman’s Beef Association --a summary of a report on a study in Denmark about eliminating antibiotics from animal feed.
EU bans farm antibiotics

A BBC article which discusses the ban on antibiotics in livestock feed.
Miracle Drugs vs. Superbugs

 An FDA review of the dangers of antibiotic resistance and an overview of the problem of overuse in humans and in animal medicine.
Backgrounder: Antibiotics in Livestock and Poultry Feed

An article from the Food Marketing Institute about the use of antibiotics in animal feed.
Why In-Feed Antimicrobials?

Article from the National Office of Animal Health in Britain?advocating controlled uses of subtherapeutic levels of antibiotics in feed
Microbes: What Doesn't Kill Them Makes Them Stronger.

Excellent kid friendly explanation of antibiotic resistance in general and each of the 3 topics addressed in this lesson from the Why Files
The Problem of Antibiotic Resistance

NIH site with good general information about the consequences of antibiotic resistance and has good links to other resources.

Per class
  • Evolving Resistance--Standards  (View)
  • Evolving Resistance--Answer Sheet for Why Does Evolution Matter Now  (View)
  • Evolving Resistance--Answer Key for The Evolution of Superbacteria  (View)
  • Evolving Resistance--Natural Selection Demonstrations  (View)
as determined by instructor
  • large bed sheet (if not going outside) with many small pieces of colored yarn of at least two different colors, one of which is the same color as the sheet (or green if going outside on the grass).

  • Evolving Resistance--Research Sheet  (View)
  • Evolving Resistance--Natural Selection in a Nutshell  (View)
  • Evolving Resistance--The Development of Superbacteria  (View)
  • See Natural Selection Demonstrations for other ideas needing other easily obtained supplies (Teddy Grahams, utensils, nuts, raisins, m&m's etc.)
Per student team/group of 3-4
  • Computer with internet access and PowerPoint, if students choose to do PowerPoint presentation. If computers with internet access are unavailable, the teacher can print selected documents for students to use for their research.

  • Evolving Resistance Resisting Antibiotics Investigation  (View)
Per Student
  • Evolving Resistance-- Summary Sheet  (View)
  • Evolving Resistance--Presentation Rubric  (View)
  • Evolving Resistance-- Poster Grading-Rubric (can use multiple copies per student if used for students to evaluate each other's work)  (View)
  • Evolving Resistance--The Evolution of Superbacteria  (View)
  • Evolving Resistance--Why Does Evolution Matter Now  (View)
  • Evolving Resistance-Reflection  (View)

  • antibacterial - an antiseptic substance; a naturally occuring or man-made agent that kills or prevents the reproduction of bacteria on the external surfaces of an organism
  • antibiotic - an agent that destroys bacteria: a naturally produced substance that kills or prevents reproduction of bacteria, but has no effect against viruses; also has little or no effect on the host of a bacterial infection and so is used as a medication
  • antibiotic resistant - bacteria that are not kiiled by one or more antibiotics.
  • evolution - the theoretical process by which all species develop from earlier forms of life. According to this theory, natural variation in the genetic material of a population favors reproduction by some individuals more than others, so that over the generations all members of the population come to possess the favorable traits.
  • microbe/microorganism - an organism too small to be seen with the naked eye.
  • prophylactic - protecting against infection or disease; "the prophylactic use of antibiotics" refers to administering antibiotics before an infection is present
  • selective pressure - pressure on species to change in response to a specific change in the environment
  • triclosan - a chemical which kills both bacteria and fungi, used in soaps and other consumer products


Initially, students will watch the video about tuberculosis in Russian prisons. They can watch as a class, or they can watch in groups (or individually) at computers. They will be required to complete THE EVOLUTION OF SUPERBACTERIA or WHY DOES EVOLUTION MATTER NOW while watching. The concept of evolution by natural selection can then be introduced or reviewed. Explain that antibiotic resistance is NOT CAUSED by antibiotics, but is one of many naturally occuring variations among bacteria. This resistance gives those bacteria a competitive advantage when antibiotics are introduced.

The video does not make clear that when a patient takes a full course of antibiotics, the few resistant bacteria which naturally occur are not killed off by the antibiotics. Those are killed by the patient's immune system, which has only those few to deal with. However, if a patient doesn't take a full course of antibiotics the patient's immune system has to try to kill off all the resistant bacteria in addition to any others remaining (not resistant, but missed because of insufficient antibiotics). Often, only a portion of the resistant + other remaining bacteria can be killed off by the immune system. The proportion of resistant bacteria among all the bacteria that are now left is much higher than it was originally. As they multiply and the cycle repeats, and resistant bacteria become the dominant type.

After the discussion of the specific case in the video, students will explore factors which may be contributing to the increased levels of antibiotic resistance we are now seeing. In small groups, they will examine each and decide if they think it is a significant contributor to the problem. They will have to explain the pros and cons of changing that factor so that it no longer contributes to increasing antibiotic resistance. Each group will pose as a public health authority and make a presentation to the class about their findings. Alternatively, each small group can choose one of the factors and make a presentation or poster which explains that issue.

1st day: Evolution of Superbug
Daily Challenge Question: How do antibiotic resistant organisms evolve?
1 45 minute period
Set-up Directions:

Either the whole class can watch the video on one screen using a computer with a projector, or small groups of students can watch it on computers. The computers will need Real Player or Windows Media. Quality on a large screen may be poor.

Each student should have the handout: Evolution of  Superbacteria or Why Does Evolution Matter Now?

Natural selection in a Nutshell and The Development of Superbacteria should be available for all students to see, on the computer, as a handout or enlarged and posted.

per group or class: large bedsheet (if not going outside) and many pieces (4-5 inches long) of at least 2 colors of yarn.At least one of the colors of yarn should be the same as the color of the bedsheet, or should be green if doing the activity outside on the grass.

Teacher Presentation & Motivation:

The video should capture the attention of the students. They will only watch the first minute before doing the activity. The activity will allow students to make evolution by natural selection "happen". Obviously this is quite an oversimplification. Have students connect the video to the  yarn worms activity.

If evolution has to be introduced rather than reviewed this will take more than one class period.

Activity 1 - Naturally Selecting

There are two choices for worksheets to use with the video. They have slight differences. Have the students fill out Part A of  EITHER Evolution of Superbacteria or of Why Does Evolution Matter Now? while watching the first segment of the video.

Stop the video after the line "the helpful ones or the harmful ones" after approximately 1 minute .

Discuss evolution. What does it mean that we play a role in the evolution of microbes? Get the students' ideas, but come to no conclusions.

Do the activity--?Worms in the Yard? (or ?Worms on the Sheet?) Take students to a grassy area or spread a sheet on the floor. Evenly spread out the pieces of yarn (the more you use, the better) over the background. Tell students that they are a predator (such as a bird) and that the pieces of yarn represent prey (worms). Discuss why the ?prey? vary in color (different genes--naturally occuring variation). Allow students to ?eat? as many prey as they can in 1 minute by picking up the pieces of yarn. Students should notice that the yarn that matched the color of the background remained (it was not eaten); these worms were best suited for their environment and thus survived, reproduced, and passed on their genes (natural selection). The surviving ?worms? reproduce (at this point add more of that colored yarn). Discuss how the population of prey has changed over time, from having many colors to only having one.

Make sure they understand the concept here, and show the graphic NATURAL SELECTION IN A NUTSHELL.. Discuss how what happens to the bugs in the graphic is analogous to what happens to chips of the same color, is analogous to what happens to bacteria that are resistant to antibiotics. Use the graphic DEVELOPMENT OF SUPERBACTERIA to help reinforce this.

Return to the idea of how we play a role in microbial evolution--how is this similar to the yarn worms.


Focus for Media Interaction
Focus for Media Interaction: The focus for media interaction is a specific task to complete and/or information to identify during or after viewing of video segments, Web sites or other multimedia elements.

Students will record what a microbe is and explain what role microbes play in disease.

Viewing Activities
What will your students be responsible for while viewing this piece of multi-media or video?


Post Viewing Activities
How will students utilize the information they gathered while viewing the multi-media or video?

Students will do the activity with the yarn worms and describe how it is similar to microbial evolution.

Refer back to the worms that are on the sheet (be sure to have all of the worms back on the sheet). Explain that the yarn now represents bacteria. Briefly discuss why there are differences in the bacteria even though they are all the same type. Tell students that the yarn pieces the color of the sheet represent bacteria that have mutated DNA and so are resistant to antibiotics. Demonstrate the effects of the antibiotics by removing the yarn that does not contain the mutated DNA. Now, what remains are the resistant bacteria that will not be affected by the antibiotic.

Show the graphics again (Natural Selection in a Nutshell and The Development of Superbacteria). Return the discussion to TB and the dangers of incorrect antibiotic use. Remind the students that resistant bacteria are naturally occuring whether antibiotics are present or not. It is the presence of antibiotics that makes the resistant bacteria more "fit" to survive.

Activity 2 - Tuberculosis, Evolution and You

Students will watch the portion of the video which describes tuberculosis and fill in Part B of the Evolution of Superbacteria  or of Why Does Evolution Matter Now? worksheet. Make sure the students understand the main parts: caused by bacteria, spread by coughing, what multi-drug resistant TB means.

Watch the rest of the video and have students complete the comparison on the sheet among the bacteria, the bugs in the diagram and the yarn worms from the activity.. Review this again to make sure they have understood the concepts.


Focus for Media Interaction
Focus for Media Interaction: The focus for media interaction is a specific task to complete and/or information to identify during or after viewing of video segments, Web sites or other multimedia elements.

Students will be responsible for recording specific information about TB, and they will have to compare the evolution of drug resistant TB bacteria to the simpler examples of bugs and yarn worms.

Viewing Activities
What will your students be responsible for while viewing this piece of multi-media or video?

Students will have to Part B of the Evolution of SuperBacteria or of Why Does Evolution Matter Now? worksheet.

Post Viewing Activities
How will students utilize the information they gathered while viewing the multi-media or video?

Students will be able to explain how the bacteria evolve due to the pressures of the antibiotic. They will use this in the next lesson on antibiotics in the environment.

Wrap Up:

Review the comparisons between the bacteria, the yarn worms and the bugs in the graphic. Refer to the end of the video--why do we care what is going on half a world away? Make sure the students understand that in this day and age, nothing is local, and germs may spread very quickly! Review with the student the concept of antibiotic resistance and why it is a problem. Some of the websites listed in resources have excellent overviews of the issues.

2nd & 3rd days maybe more: Wherefore antibacterials?
Daily Challenge Question: What are some of the sources of antibacterials that may be leading to the development of resistanct organisms? What are the advantages to reducing their use? What are the risks of reducing their use?
2-4 45 minute period
Set-up Directions:

Two different options are presented for this portion of the lesson. They have the same aim, but are structured slightly differently. One is described as Activity One, and one as Activity Two. A class should do one OR the other.

For both versions each group of students will need access to a computer with internet access, or articles (from websites) printed out by the teacher. They will also need PowerPoint, or materials to make a poster or oral presentation (this can be teacher or student choice). It will be a time saver if the websites you want students to visit are bookmarked.

For Activity One:  Each group of students will need a RESEARCH SHEET and the PRESENTATION RUBRIC for development and evaluaion of their presentation

Each student will need the SUMMARY SHEET.

For Activity Two:    Each group of students will need RESEARCH OUTLINE.


The class will also need  a number articles printed out, put in folders, and numbered.                                                  

Teacher Presentation & Motivation:

In this part of the lesson students willl investigate selection pressures that may contribute to the development of antilbiotic resistance, and explore the consequences of reducing those pressures.On the first day(s) students will do research, and on the last day the students will present their findings to the class in a PowerPoint presentation, poster, or skit. The three areas to research are: antibiotic overuse in health care, antibiotic use in animal feed, and antibacterial use in soaps and other household items  Students can select one of these topics (making sure that each is covered) or they can be assigned by the teacher (in Activity 2 the students choose), The method of presentation can likewise be determined by the students or by the teacher.

If, after doing their ressearch, students feel that levels of antibiotic/antibacterial use should be maintained that could be the focus of their presentation. If they feel it should be reduced, that could be their focus. They can also take a neutral stance, explaining each position. Two groups arriving at different conclusions can provide a good opportunity to discuss what constitutes good data, understanding bias in data sources, and potential differences in data interpretation. Bias is addressed directly in Activity 2.

The students should be introduced to the difference between and antibiotic and an antibacterial. An antibiotic is a naturally occuring substance that kills or prevents multiplication of bacteria; many are now man-made, but the original antibiotics came mostly from fungi. Antibiotics, by definition, do not harm the host and so are useful for treating infections. Antibacterials kill or prevent multiplication of bacteria on the external surfaces of the body, but cannot be ingested like antibiotics can.. At the end of the lesson this distinction can be reviewed  by the groups that investigated consumer products.

Hopefully the previous day's lesson will spark interest in this topic, and students will be eager to know how they can help prevent rapid development of antibiotic resistance. For some students the animal feed topic will be least relevant to their immediate lives. The relevance of this can be demonstrated by showing the students organic milk, egg, chicken, beef, etc. wrappers that say "no antibiotics in feed" . This topic will help them decide  if this is an importatnt label to look for when purchasing food.

Activity 1 - Research

Students will research their assigned topic using the internet sites provided and present their findings to the class. They will use the RESEARCH SHEET as a guide to what they should include, and receive a copy of the PRESENTATION RUBRIC so they know exactly what is expected.

Focus for Media Interaction
Focus for Media Interaction: The focus for media interaction is a specific task to complete and/or information to identify during or after viewing of video segments, Web sites or other multimedia elements.

For each topic students will use the websites to complete their research sheets on which they should detail:

What the problem is
Why it is a problem
What are the advantages and disadvantages of cutting back on this use 
Their opinion and ideas for strategies to convince people to reduce (or maintain) current levels of use.

Some general websites:

Miracle Drugs vs. Superbugs

Microbes: What Doesn't Kill Them Makes Them Stronger

The Problem of Antibiotic Resistance

 Websites specific to the topics:

antibiotics in animal feed

Antibiotics in Livestock and Poultry Feed

WHO:Farmers Should Cut Antibiotic Use

EU Bans Farm Use of Antibiotics

medical use of antibiotics

The Overuse of Antibiotics

CDC expands campaign against overuse of antibiotics

Using Antibiotics Sensibly

antibacterials in household soaps and cleansers

Study Washes Away Antibacterial Claims

FDA advisors say...

Antibacterial Cleaning Products and Drug Resistance

Antibacterial Products Play an Invaluable Role



Viewing Activities
What will your students be responsible for while viewing this piece of multi-media or video?

While gathering the information, the students will fill out the research sheet. They can decide if the use assigned them constitutes overuse and should be cut back, or if it is justified and the risk of creating antibiotic resistance is worth taking.

Post Viewing Activities
How will students utilize the information they gathered while viewing the multi-media or video?

Students will create a presentation in which they aim to educate the audience about their topic and present logical and scientific arguments to reduce (or maintain) current levels of antibiotic use. They are expected to explain the concerns about reducing (or maintaining) the level of antibiotic use. Students also will be expected to explain how antibiotic resistance is promoted by the use of antibiotics in the way they have researched.

While listening to the presentations of other groups, students can fill out the  SUMMARY SHEET. They can include their own presentation information on it as well. By the end of all the presentations, they should have a good summary of the topic. This can be collected and used as  an assessment if the teacher would like.

Activity 2 - Research--Plan B

Each student should receive a copy of RESISTING ANTIBIOTICS INVESTIGATION worksheet. The numbered  folders with the print outs should be distributed around the room. Students will "speed research" They are given 3-5 minutes with a folder.  They find which general category it fits into (Agriculture, Home,Personal, Medical) and write the source number. They then write direct statements taken from the article in the appropriate column (Pro or Con that use of antibiotic/antibacterial). After 3-5 minutes they switch and do the same with a different article. Each student should be able to review 7-10 articles in a 45 minute class period. Once finished with this "speed researching" students should get together with their group and decide which of the general categories they want to research further.

Going back to the sources they have looked at, and researching others (online if possible), students work on RESEARCH OUTLINE worksheet as a group. The students can also be given a copy of the POSTER GRADING RUBRIC  at this point so they know what is expected.

 In the process of completing the Research Outline, students should evaluate two of the articles they are using for bias. This is addressed in question 10 of the research outline. At some point while students are doing their research, a class discussion about what bias is, how to spot it and why there is bias in articles would be appropriate. Students should be able to cite examples from the resources they have used.

Finally, students work on the final poster, or presentation (the materials attached here are for a poster, but can be modified for a PowerPoint or other presentation type). Once all are completed, they are posted in a central location and each student gets 5  GRADING RUBRICS to complete on 5 different posters. In addition, each student should receive a REFLECTION to complete, grading themselves and the other members of their group. The Research Outline of each group can also be assessed by the teacher.

Focus for Media Interaction
Focus for Media Interaction: The focus for media interaction is a specific task to complete and/or information to identify during or after viewing of video segments, Web sites or other multimedia elements.
Students will identify and describe the issues surrounding one use of antibiotics/antibacterials. In addition, they will look for bias in sources they examine.
Viewing Activities
What will your students be responsible for while viewing this piece of multi-media or video?
In completing the RESEARCH OUTLINE students will define key vocabulary, and write down 5 direct quotes from the sources of important points. They will also examine two sources for evidence of bias.
Post Viewing Activities
How will students utilize the information they gathered while viewing the multi-media or video?
Students will use the completed outline to create a poster or presentation. They will critically evaluate the work of their group, and that of others.

Wrap Up:

Once all groups have made their presentations, review the pros and cons of the limitations of each. This is a very good example of hard choices, but where good scientific data can really help make good decisions. Discuss with students how they can explain the issues to others. Bring the discussion back to evolution and review the process by which each of these factors will promote the evolution of resistant bacteria.

Enrichment Options
Community Connection

Have students go to their doctors' offices and see if there is information about appropriate use of antibiotics.

If there are farms in your area, have students interview the farmers about their use of prophylactic antibiotics.

Conduct a survey of "people on the street" about antibacterial soaps. Prepare a presentation for other children about how to wash their hands properly.

Parent-Home Connection

Have students prepare Fact Sheets about antibiotic overuse and antibacterial soap to bring home and share with their families.

Field Experiences

Go to a local hospital (or have a representative come to your class) to discuss the problem of antibiotic resistant infections.

Cross-Curricular Extensions

Social Studies/Geography--Investigate availability of antibiotics in different countries and the prevalence of resistant organisms in those areas. (If you can get data, this could be a good GIS activity)

Environmental Science--Investigate the environmental effects of Triclosan (the active ingredient in many antibacterial soaps)

Math--Bacterial multiplication rates can be used in math class to explore exponential growth,  and relative numbers of resistant and non-resistant organisms can be used to explore ratios.

Stage 4
Teacher Reflection

Author: Elissa Hozore
Modified by: Larry Sickels, Tim Rhue, Nancy Miller, Sarah Smith
Program: EnviroHealth Connections