Constructing Ecosystem Models

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SWBAT make a model of an aquarium ecosystem and a terrarium ecosystem.

Big Idea

In this lesson, students will attach two large plastic bottles to create a ecocolumn, with an aquarium ecosystem in the bottom bottle and a terrarium ecosystem in the top bottle.

Lesson Overview

Inquiry Based Instructional Model

To intertwine scientific knowledge and practices and to empower students to learn through exploration, it is essential for scientific inquiry to be embedded in science education. While there are many types of inquiry-based models, one model that I've grown to appreciate and use is called the FERA Learning Cycle, developed by the National Science Resources Center (NSRC):

1. Focus

2. Explore

3. Reflect

4. Apply

A framework for implementation can be found here

I absolutely love how the Center for Inquiry Science at the Institute for Systems Biology explains that this is "not a locked-step method" but "rather a cyclical process," meaning that some lessons may start off at the focus phase while others may begin at the explore phase. 

Finally, an amazing article found at, How Inquiry-Based Learning Works with STEM,very clearly outlines how inquiry based learning "paves the way for effective learning in science" and supports College and Career Readiness, particularly in the area of STEM career choices. 

Unit Explanation

In this unit, students will first develop an understanding of the biotic and abiotic factors within ecosystems, the characteristics and classification of living organisms, and how plants and animals obtain and use energy to fulfill their needs. 

Then, students will delve deeper into the NGSS standards by examining the interdependent relationships within an ecosystem by studying movement of matter between plants, animals, and decomposers by creating models of food chains and food webs. 

At the end of this unit, students will study ways that individual communities can use science ideas to protect the Earth's resources and environment.  

Summary of Lesson

Today, I will open the lesson by asking students to use yesterday's research to revise their team's ecosystem definitions. Students will use the rest of the lesson time to attach two large plastic bottles to create a ecocolumn, with an aquarium ecosystem in the bottom bottle and a terrarium ecosystem in the top bottle.

Next Generation Science Standards  

This lesson will support the following NGSS Standard(s):

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.  

5-LS1-1.    Support an argument that plants get the materials they need for growth chiefly from air and water.  

5-LS2-1.    Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.  

Scientific & Engineering Practices

For this lesson, students are engaged in the following Science & Engineering Practice(s):

Science & Engineering Practice 2: Developing and Using Models

Students will develop a model of real world ecosystems in order to better understanding of larger, naturally occurring ecosystems.

Crosscutting Concepts

To relate ideas across disciplinary content, during this lesson I focus on the following Crosscutting Concept:  

Crosscutting Concept 4: Systems and System Models

Students will begin defining their system models as a "terrarium" and "aquarium." Later on, they will use this model to examine the functions of individual parts within each ecosystem.

Disciplinary Core Ideas

In addition, this lesson also aligns with the Disciplinary Core Ideas

PS3.D:  Energy in Chemical Processes and Everyday Life

The energy released [from] food was once energy from the sun that was captured by plants in the chemical process that forms plant matter (from air and water). (5-PS3-1)

LS1.C:  Organization for Matter and Energy Flow in Organisms

Food provides animals with the materials they need for body repair and growth and the energy they need to maintain body warmth and for motion. (secondary to 5-PS3-1)

Plants acquire their material for growth chiefly from air and water. (5-LS1-1)

LS2.A:  Interdependent Relationships in Ecosystems

The food of almost any kind of animal can be §traced back to plants. Organisms are related in food webs in which some animals eat plants for food and other animals eat the animals that eat plants. Some organisms, such as fungi and bacteria, break down dead organisms (both plants or plants parts and animals) and therefore operate as “decomposers.” Decomposition eventually restores (recycles) some materials back to the soil. Organisms can survive only in environments in which their particular needs are met. A healthy ecosystem is one in which multiple species of different types are each able to meet their needs in a relatively stable web of life. Newly introduced species can damage the balance of an ecosystem. (5-LS2-1)

LS2.B:  Cycles of Matter and Energy Transfer in Ecosystems

Matter cycles between the air and soil and among plants, animals, and microbes as these organisms live and die. Organisms obtain gases, and water, from the environment, and release waste matter (gas, liquid, or solid) back into the environment. (5-LS2-1)

Choosing Science Teams

With science, it is often difficult to find a balance between providing students with as many hands-on experiences as possible, having plenty of science materials, and offering students a collaborative setting to solve problems. Any time groups have four or more students, the opportunities for individual students to speak and take part in the exploration process decreases. With groups of two, I often struggle to find enough science materials to go around. So this year, I chose to place students in teams of three! Picking science teams is always easy as I already have students placed in desk groups based upon behavior, abilities, and communication skills. Each desk group has about six kids, so I simply divide this larger group in half. 

Gathering Supplies & Assigning Roles

To encourage a smooth running classroom, I ask students to decide who is a 1, 2, or 3 in their groups of three students (without talking). In no time, each student has a number in the air. I'll then ask the "threes" to get certain supplies, "ones" to grab their computers, and "twos" to hand out papers (or whatever is needed for the lesson). This management strategy has proven to be effective when cleaning up and returning supplies as well!  


20 minutes

Lesson Introduction & Goal 

I introduce today's learning goal: I can make a model of an aquarium ecosystem and a terrarium ecosystem. I explain: Today, each science team will work together to build an ecocolumn. Referring to the following Eco-Column Diagram, I continue: An ecocolumn is made up of two, 2-liter bottles. The bottom bottle is set up as an aquarium. This is a water ecosystem as "aqua" means water. The top bottle is set up as a terrarium, which is a land ecosystem as "terra" means land. During our ecosystems unit, it is important to have models of ecosystems on hand so that you can actually observe the interactions between the plants and animals as well as the changes that occur over time (instead of just reading about them). 

Revising Definitions 

Before we start building our ecocolumns, let's return to our ecosystem definitions from yesterday (Student Ecoystem Definitions). Why is revision an important part of both the writing and science process? Students offer, "Because revisions help make your writing better," and "Now that we know more, we can change our sentences to match our thinking." 

As a side note, anytime I can integrate the writing process into science, I do, as it helps bring relevancy to language arts. 

I ask one student from each group to grab their definitions and for each team to use their notes from yesterday's research to revise their definitions. Once finished, students tape their revised definitions back up on the front board. 

Monitoring Student Understanding

Once students begin working, I conference with every group. My goal is to support students by asking guiding questions (listed below). I also want to encourage students to engage in Science & Engineering Practice 7: Engaging in Argument from Evidence

  1. What is an ecosystem?
  2. Why do you suppose ____? 
  3. Has your thinking changed? 
  4. Can you use a more precise word?
  5. Can you explain how your research supports your thinking?

Student Conferences 

During this conference, Making Clear Definitions, the students explain that an ecosystem is "where living and nonliving things live." I ask: Are nonliving things alive? Is a rock alive? How can you change your wording? I want to encourage this group to attend to the clarity of their definition. 

This group, Developing Precise Definitions, is trying to decide if an ecosystem is the same thing as a habitat. One text that they read yesterday explains that a habitat (home for a species) can be an ecosystem. However, it doesn't point out that an ecosystem can have more than one habitat. I try to guide the students as they construct meaning around these two terms. If we had more time, I would have them look it up. However, having done so myself, I know how challenging it is to find a resource that simplifies the comparison between these concepts! 

Sharing Definitions

After students revise their definitions, they tape them back on the board. We take about 5 minutes to read and discuss each definition. I wished we would have had more time, but I knew that we needed to devote as much time as possible to building student eco-columns!

With each definition, I continually ask students questions to encourage student engagement: Do you agree? Did anyone else use the terms amitotic and biotic? 


70 minutes

Ecocolumn Bottles

To have enough materials for each group to construct an Ecocolumn, I collect and cut 20 two liter bottles so that each group would have 2 two liter bottles: Cutting Bottles.

The Bottom Bottle (Aquarium)

For one bottle, I cut off the top couple of inches, including the cap. A sharp pair of scissors surprisingly works great! At first, I cut too many inches off, as you can see in this picture: Enlargening the Aquarium. The bottle on the right is my first try, but I want the aquarium to be larger. After all, students will be placing two goldfish in this part! The bottle on the left turns out to be perfect. I simply cut about 1.5 inches above the label line. 

I also drill a little feed hole into the wall of this bottle (at the very top) so that students can feed their fish. Later, I'll find out that this hole doesn't work very well for flake food so I'll make a trip to the store to buy goldfish pellets!!! 

The Top Bottle (Terrarium)

For the other bottle, I drilled a hole in the cap and cut around the bottle about 5 inches up (Cutting Bottles). I left about a half inch uncut so that the bottle could flap open for easy assembling. 

Setting up

Today's lesson takes a lot of preparation! I actually ask if any students would like to volunteer to set up for science during lunch recess. It takes at least ten excited student volunteers to set everything up! 

Team Boxes

In each of the labeled Team Boxes, we place the following Team Supplies:

  • three handheld magnifying lenses
  • an 8 inch piece of yarn 
  • a 100 mL graduated cylinder
  • a 1/2 cup of pebbles
  • 1/4 cup of rocks (gravel) 
  • 2 cups of soil
  • a bag of leaves
  • 2 paperclips 
  • a team label (for Labeling Ecocolumns, here are the Team Labels)

Leaves: Even though the leaves are not necessary, I want to provide students with opportunities to make decisions about what to do with the leaves and to inspire conversations about composing! 

Bottles: I place the two types of Bottles at the front of the room. My goal is to make sure all supplies aren't in one location. This can make it more difficult for students to efficiently collect supplies.

Placemats: I also set out Placemats for each team to help control the mess. As a side note, I picked up these placemats at garage sales for really cheap! 

Other Materials

Next, students help set distribute GoldfishSnailsDuckweed, and Elodea into cups. This way, these live materials will be easy for students to grab later on! 

Seeds were also set up along another counter. I cut 40 sheets of paper (4 seeds x 10 teams) and place a small pile of each type of seed on the papers: Corn SeedsBarley SeedsPea Seeds, and Radish Seeds. Students then place a plant label on each paper for labeling ecocolumns later on (Plant Labels). This also makes it easy for students to gather the correct seeds. 

Modeling How to Make the Aquarium

To set students up for success, I invite students to the back table so I can model how to construct the aquarium step-by-step: Making the Aquarium. During this time, I make sure to hit the following points: 

  • How to explicitly add each component
  • Having respect for living organisms
  • Using chlorine-free water (instead of using water from the tap)
  • Completing "terrarium checks" along the way to make sure the cap of the terrarium doesn't hang down into the water 


Getting Materials

Students are excited and can't wait to begin! I ask students to return to their desks and then, I ask my #1 students on each team to get the bottles, #2 students to get their corn seeds, #3 students to get the team boxes, and so on, until all supplies are gathered. This material distribution method works out great!! 

Modeling How to Make the Terrariums

After students have their aquariums built, I show students the following diagram on the board, Seed Diagram, and I explain how to section off the terrarium, dedicating one fourth of the soil to each type of seed. Then I invite students to the back table so I can model how to make the terrarium: Making the Terrarium. Key points that I make sure to include are: 

  • Placing the string up through the soil instead along the side (I'm not sure why! I just remember reading about this recommendation when researching ecocolumns!) 
  • Using the paperclips to hold the terrarium open
  • Planting and labeling seeds
  • Taping the ecocolumn together


Monitoring Student Understanding

Once students begin working, I conference with every group. My goal is to support students by asking guiding questions (listed below). I also want to encourage students to engage in Science & Engineering Practice 7: Engaging in Argument from Evidence

  1. What are you working on? Why?
  2. Why do you suppose ____? 
  3. Has your thinking changed? 
  4. How did you decide what to do with the leaves?
  5. How is this aquarium/terrarium an ecosystem? 

Student Conferences

I have to say that I was unable to conference as much I would have liked to! Lending a helping hand and monitoring the building process took priority! During this conference, Making Science Connections, you'll see that the students were unable to release the goldfish as easily as I was able to during my demonstration. Most groups had to tip their aquariums to pour the goldfish and water into their aquariums. During our conversation, I was happy to hear students making the connection between their ecosystem research yesterday and their models! 

Student Work

Students just barely have enough time to finish their ecocolumns and to clean up! I ask students to place their ecosystem models on the back table. I add clear tape to close the terrariums and duct table to hold the terrarium and aquarium together. Then, I set all the ecocolumns next to the window: Class Ecocolumns and Class Ecocolumns 2

Ooops! We forgot to add water today, so we take some time to do this tomorrow! Students agree to add 100 mL of water. After adding water, most groups have to add more soil to cover the seeds and had plenty of soil left in their team boxes to do this! We then seal up the terrarium with tape and will not need to add water again!