What is a Feedback Loop, Anyway?
Lesson 4 of 9
Objective: SWBAT to explain the concept of a feedback loop and give specific examples of feedback loops in the human body systems.
The idea of a feedback loop is a big part of human physiology and one that most students don't clearly understand through their individual and group project work. I believe it to be a fundamental concept related to homeostasis and this activity is a great way to relate stories to content in a way that engages students in higher level thinking.
To honor our Common Core implementation this year, I am adding an additional individual writing component to the original activity which includes a group poster creation and presentation and have created a rubric for the writing piece as well.
This lesson is one I am still tweaking for the best impact on my students. I will look forward to hearing your ideas to enhance it further for student learning!
1. Ask student lab groups to discuss the following prompts:
What is a feedback loop?
Give an example of something you think might be a feedback loop.
2. Using the spokesperson protocol, allow students to share out their responses briefly.
- Note: Students will not necessarily have a lot to say about feedback loops. They might be able to tell you that there is an action and then a response but not always. Sometimes, if I prompt them with an example of fight or flight (adrenaline/noradrenaline), that will get students thinking about them with more insight. If you have a class that understands the basics of feedback loops, challenge them with an additional prompt contrasting negative and positive feedback loops.
3. Announce that today we will be investigating the concept of feedback loops and how they relate to homeostasis.
4. Show this five minute video clip as an introduction to the activity. Tell students to listen carefully to the video with our prompts about feedback loops in mind:
5. After this video clip ends, ask students to again look at the prompts from the start of the class and to discuss any changes in their answers since finishing the video clip viewing session.
6. Using the spokesperson protocol, ask students to share out their new and improved responses. Students should be able to tell you that feedback loops are way for the body systems to continually monitor and respond to changes that might affect homeostasis and that every feedback loop system has two opposite responses ready to offset shifts away from homeostasis in either direction (too much or too little of anything).
7. Tell students that today they will be learning more about homeostasis and feedback loops in human body systems by investigating and representing specific feedback loops found in the human body systems.
1. Tell students that they will be working in their lab groups to create a poster to present to the class later in the class period describing a feedback loop associated with a specific scenario.
2. Give students their start and end time, show where the paper and markers are located in the room, and ask one representative from each group to come up to get their group's scenario. All scenarios are found on this human body systems Feedback Loops for Homeostasis Scenarios document. This document contains page references where students can find information about their feedback loop in our textbook, Campbell's Biology: Exploring Life textbook published by Pearson/Prentice Hall.
3. Before dismissing students to move to their lab tables and begin working, point out the board prompts students will be using to present their scenario. Remind students that each group will receive 1:10 minutes and that each person must contribute to the oral presentation in some way. Remind students of our basic oral presentation guidelines posted on the board and on this presentation guidelines document.
4. Observe groups as they work, allowing them to work through challenges as a team as much as possible
5. Announce time for students to keep them on track. This is not supposed to be an art gallery worthy diagram! Stick to your timeframe and students will be able to meet those expectations with your frequent and gentle reminders.
- Note: Check out this feedback loop poster student work sample for guidelines about visual quality level. In terms of content, this poster shows the basics of the feedback loop that happens when a person's body temperature becomes elevated. From this work, I can see that additional questioning about the specifics of how it ties into a negative feedback loop could be a helpful clarifying conversation for students. I can also ask students for more detail in terms of what blood vessels are dilated (typically, arterioles) and I can also ask for or offer the names of chemicals that the hypothalamus use as messengers to start that process throughout the body.
1. Announce that each group will present their feedback loop by addressing the following questions posted on the board:
- What was your scenario? (read it)
- What system, organs, hormones, and/or neurotransmitters are involved?
- What happens?
- Is this a negative or positive feedback loop and why?
- How does this relate to homeostasis?
Note: all group members must contribute to the brief oral presentations. Set a timer for 1:10 minutes for each group to keep the teams on track!
2. With the remaining minute, address any concerns or questions student may have. Students will be curious about positive feedback loops and when they might occur. I give two classic examples from the female reproductive system: milk production and uterine contractions. The conversation at that point will turn to the observation that there are a lot more negative feedback loops as a regulating mechanism. This is also a good time to bring up how specific medications work, specifically neutrotransmitter replacements for the treatment of depression symptoms.
1. Pass out the feedback loop scenario writing prompt document.
2. Tell students that this prompt document is their individual follow up work for this lesson.
3. Give students the remaining time to discuss their scenarios within their lab team, look up information in their textbook, and/or plan out their writing. In this SW feedback loop conclusion statement,the student shows a basic understanding of the main parts of a feedback loop. I would add revision suggestions here to prompt the student to add more detail about the specific body system mechanisms involved in his chosen feedback loop example.