Lesson 6 of 7
Objective: Students will be able to recognize the role of evolution in antibiotic resistance.
Warm-Up: Many insects become resistant to pesticides. In which population of insects would you MOST expect pesticide resistance to develop?
- A population that is never exposed to the pesticide
- A population that reproduces very slowly
- A population that is completely killed off by the pesticide
- A population that reproduces quickly
This question serves as a review of concepts addresses in evolution 1 and evolution 2. Make sure that students possess an understanding of the term, resistance before they attempt to answer the question. Sometimes a lack of vocabulary acquisition makes it difficult for students to identify a correct answer, even when they might understand the concept but can’t identify a correct answer because of vocabulary deficits.
Once the meaning of the term, resistance is established, look for students to be able to identify that a population that reproduces quickly is more likely to have more genetic variation or differences so there would be greater resistance in the group than the others.
This question also sets the stage for the coming discussion on antibiotic resistance by introducing the concept of resistance.
Introduce New Material
Inform students of the learning targets:
- I can explain the role of evolution in antibiotic resistance.
- I can explain how antibiotic resistance might be helping the spread of disease.
- I understand how antibiotic resistant bacteria multiply and why they are a problem.
Introduce the vocabulary associated with the lesson: mutation, speciation, variation, antibiotic, antibiotic resistance, trait, and microbe. Plan to explicitly teach the vocabulary associated with the lesson at the appropriate times within the lesson. Make sure that students add the bolded terms to their vocabulary maps as has been practiced throughout the year for terms that have Greek or Latin root words, prefixes or suffixes.
Begin with a brief animation on antibiotic resistance that provides a simple and easily understood explanation of antibiotic resistance. Note: I like this short clip because it has a student-friendly presentation while still being informative.
Make sure students know the purpose for viewing by previewing the questions that they should be able to answer after viewing the clip:
- What is an antibiotic?
- How does antibiotic resistance occur?
- What does antibiotic resistance mean?
- How is resistance transferred to other bacteria?
Review the questions and responses whole group after the brief clip. Allow students to share their thoughts. Be sure to re-state correct responses so that all students gain an understanding of the correct response to each question.
Explain that students will watch a video, Hunting the Nightmare Bacteria to gain a real-world and current perspective of the issue.
Establish the viewing expectations before starting the video, making sure that students know that they must write at least 10 things that they learned from the video. If time does not allow for a complete viewing of the video, shorten viewing to the first 30 minutes. Note: Although this video is a long segment, students will find it highly engaging and interesting.
After the video, reinforce the learning from the video by engaging students in a “round robin” sharing of facts, ensuring that each student in the class shares at least one fact that they learned from the video.
Inform students that they will participate in an antibiotic resistance simulation.
Using a LCD projector, model how to access and navigate the site. Distribute computers and assign students to work in groups of two to use the site to see how resistance occurs and how treatment occurs for antibiotic resistance bacteria. Note: To save time, have the laptops on the tables before class begins.
Display simulation questions that students should answer while participating in the simulation:
- What is a latent infection?
- How does TB infection spread?
- What is the impact of treating resistance bacteria?
- Why should we complete the doses of an antibiotic?
Inform students that they will have 10 minutes to work through the simulation. Set the timer and walk around to monitor students as they work.
At the end of the time, engage students in a whole group discussion for each of the questions.
Display 3 Constructed Response Questions. Inform students that they will work independently to write responses to each the following constructed response questions:
- What can you do in your life to reduce antibiotic resistance?
- How does the overuse of antibiotics lead to resistant strains of bacteria?
- Why do bacteria become resistance more quickly than plants or animals?
Project the RACE writing strategy and encourage students to refer to it as a guide as they construct their responses. Use the LCD to project a timer using a program like cooltimer to help students manage their time. Suggest that students spend no more than 5 minutes on each question.
Walk around and provide assistance to students as they work. Look for students use of the RACE writing strategyy to organize and construct their responses. Encourage students to use their notes from the videos to support their responses.
Collect and read the work products. Look for students' ability to identify activities that will reduce their susceptibility for infection like hand-washing. Also, students' responses should indicate that natural selection favors bacteria that are less susceptible to antibiotics. Also, look for students to identify that because bacteria reproduce asexually, they reproduce more quickly that organisms that reproduce sexually. Student work 1 and student work 2 both show student responses that display an understanding of these concepts.
Because most of today's assignment has involved listening and writing, give students an opportunity to engage in academic discussion as the lesson close.
Instruct students to "turn and talk" with a seatmate about one thing that they take-away from today’s lesson. Encourage students to each speak for 1 minute before switching to the other student. Project and set the timer for one minute. Walk around and listen to students’ comments as another way to determine if students did gain an understanding about the role of evolution in antibiotic resistance, how antibiotic resistance expands and why this is a problem.