The Why Behind Teaching This:
Unit 3 addresses standards related to the transfer of energy and matter between organisms in an ecosystem. The unit begins with identifying what solar energy is and what two forms of energy solar energy provides life on Earth. This is an important foundation for understanding standard 5-PS3-1: Use models to describe that energy in animals' food (used for body repair, growth, motion, and to maintain body warmth) was once energy from the sun. We build on this knowledge throughout the unit in other lessons related to photosynthesis and how animals use the energy they get from food. In this unit students will also be conducting experiments to gather evidence to support their belief that plants get the materials they need for growth from either water, air, or the soil. This is covered in standard 5-LS1-1: Support an argument that plants fet the materials they need for growth chiefly from air and water. Students will also be creating food chains and food webs to describe the movement of matter among organisms in an ecosystem. This is covered in standard 5-LS2-1: Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.
I combined these three standards all into unit 3 because teaching them together allows students to see how they are all connected. The energy that plants get from the sun is stored in their parts until animals consume them. Plants cannot absorb this energy and reproduce without other materials from the environment such as carbon dioxide from the air, and water and nutrients from the soil. The animals that consume the plants, use part of the energy for growth, reproduction, etc. but they also store some of the energy. That energy is then passed on to other animals when they are eaten by other animals. All of the energy that is available in an ecosystem can ultimately be traced back to the sun. Teaching all of these standards together, instead of in isolation of each other, makes that connection easier to see.
This specific lesson addresses standard PS3-1: Use models to describe that energy in animals' food (used for body repair, growth, motion, and to maintain body warmth) was once energy from the sun. They will be using food webs, which is a model, to trace the flow of energy through an ecosystem noting that each food web begins with a producer which gets energy to pass on from the sun.
The goal of this lesson is for students to be able to analyze food webs to determine how changes in one population affect other populations within that ecosystem and to be able to trace the flow of energy from all organisms back to the producer and then to the sun.
Students will demonstrate success by correctly answering all questions on the exit ticket at the end of the lesson.
Preparing for Lesson:
Comparing Food Webs and Food Chains
I begin today's lesson with a review of the last two lessons. I provide each table group with a whiteboard and marker and ask them to create a Venn Diagram comparing and contrasting food chains and food webs. I am doing this to check for understanding of content taught in the previous two lessons and to ensure that students are able to compare the two models. I give them about three minutes to complete the Venn Diagram in their groups while I circulate to listen to conversations.
After about three minutes, I have each group share what they have in the center that are similarities. I draw a large Venn Diagram on the front board to combine the ideas of all groups. After all groups share the similarities, I have each group tell what they had for just the food web and the food chain. I combine the ideas shared by all groups on the diagram on the front board.
Playing the Game
I pull down the overhead screen to show the Food Web Game I created on understanding food webs. The questions require students to differentiate between producers and consumers, be able to trace the flow of energy back to the sun, and determine how the population of organisms will change as a result of the population of others changing. Groups discuss the answers and then record their answer on the whiteboard they still have at their desks. As you can see in the video of students playing the food web game, I asks all groups to hold up their boards at the same time so that others don't see their answers and then read off all answers. Any group that does not hold their board up when I ask for them will not count in that round. As groups answer questions correctly, they get to pick a card from my hand that has different amounts on the back ranging from 100 - 1,000 points. There are a couple of cards that also say, steal a card from another group, and choose a group to give this 300 point card to. Groups keep the cards they earn and add them up at the end to see who has the most points.
Students Create Their Own Questions:
In yesterday's lesson, Food Webs, each group created a poster of a food web for a given ecosystem. The posters created are still hanging up around the room. I give the following directions:
It is your turn to become part of the game. You will be using the food webs you created in the previous lesson to come up with your own game questions. Groups must come up with five questions about their food web that will be added to the game. You must also include the answer to each question on the card. Groups will not be able to earn points for the five questions they create, but all other groups that get the questions correct will. Groups can lose points for their own questions though. If the answer put on the card for their question is not correct, (I will be checking as we go over them), they will lose 200 points.
Having groups write their own questions, with answers, based on the food web they created, challenges students to develop difficult questions so that the other groups will not get the answer correct. It encourages them to really dissect the food web and look at it in a variety of ways. I provide each group with 5 index cards and send them to their poster. I give them about 10 minutes to come up with their questions while I circulate to listen to conversations and to make sure all group members are actively involved.
Groups Present Their Questions
I raise the overhead screen and move group one's poster to the front board where everyone can see it. I have group one ask their first question while all other groups record their answers on their whiteboards. Group one checks their answers and tells me which groups got it correct and get to pick a card for points. I am checking answers along with group one and notify them of any mistakes. If there are any mistakes we spend some time discussing the correct answer. After group one has asked all five of their questions, I move group two's poster to the front board and they present their questions in the same way. We continue until all five groups have asked their questions. I reward the winning team with tickets (our classroom incentive).
I provide each student with a copy of the Analyzing Food Web Exit Ticket to complete. The exit ticket requires them to analyze a food web independently and answer a variety of questions similar to those asked today. After working together with their group, the exit ticket allows me to assess if which students are able to apply what they have learned to a food web on their on. After analyzing the results from the exit ticket, I found that the majority of students missed 2 or less and the most common one missed was number 5. Question 5 asked for the original source of energy for all of the organisms in the food web. Students who missed it either put corn (the producer) or mushrooms (the decomposer). One picture below is an example of a student who put mushroom as the answer for number five. When reviewing the answers with the class, I also reviewed that the term organism refers to all plants and animals so the question is asked how all plants and animals in the food web get their energy. About half of the class answered sun on this question which was correct. The other picture below shows a student who got them all correct.