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Daily Do

How Do Shrimp Live in a Closed System?

Crosscutting Concepts Disciplinary Core Ideas Environmental Science Is Lesson Plan Life Science NGSS Phenomena Physical Science Science and Engineering Practices Three-Dimensional Learning Middle School High School Grades 6-8 Grades 9-12

Welcome to NSTA's Daily Do

Teachers and families across the country are facing a new reality of providing opportunities for students to do science through distance and home learning. The Daily Do is one of the ways NSTA is supporting teachers and families with this endeavor. Each weekday, NSTA will share a sensemaking task teachers and families can use to engage their students in authentic, relevant science learning. We encourage families to make time for family science learning (science is a social process!) and are dedicated to helping students and their families find balance between learning science and the day-to-day responsibilities they have to stay healthy and safe.

Interested in learning about other ways NSTA is supporting teachers and families? Visit the NSTA homepage.

What is sensemaking?

Sensemaking is actively trying to figure out how the world works (science) or how to design solutions to problems (engineering). Students do science and engineering through the science and engineering practices. Engaging in these practices necessitates students be part of a learning community to be able to share ideas, evaluate competing ideas, give and receive critique, and reach consensus. Whether this community of learners is made up of classmates or family members, students and adults build and refine science and engineering knowledge together.

Introduction

By middle school, students are coming to understand that organisms rely on their ecosystems to provide the matter and energy needed to survive. Students begin to make sense of how matter and energy move through ecosystems and how to use food web models to represent these movements. Today's task, How do shrimp live in a closed system, provides an opportunity for students and their families to engage in science and engineering practices and use science ideas to make sense of how the marine shrimp in an EcoSphere (closed system) can get the matter and energy they need to survive.

Shrimp in Bubble

Many people express their love of living things by maintaining aquaria that range from simple fishbowls to highly complex reef systems. Some of these can require intensive maintenance to ensure that organisms have what they need to thrive. In contrast to the typical home aquarium, ecospheres are designed to sustain the included organisms with no inputs (except sunlight) or outputs and do not require maintenance. An ecosphere can be constructed as a DIY project or purchased commercially. EcoSphere Closed Ecosystems, as shown in the photograph and video above, are commercial products that enclose filtered seawater, algae, bacteria, and marine shrimp in glass spheres. The video shows shrimp in an EcoSphere that have survived for 17 months (so far).

Note: EcoSphere is a commercial product. We use the term ecosphere to refer to any closed ecosystems (glass or plastic container with air-tight lid).

Presentation of Phenomenon (What am I exploring today?)

Use the "Surviving Inside the EcoSphere" handout to guide student thinking throughout this task. This task is adapted from Dr. April Maskiewicz's Ecosphere Problem Tasks. Show students the photograph above to introduce them to EcoSpheres, and then have them answer question 1: How long do you think the shrimp can survive inside the EcoSphere, and why do you think so? Their answers and justifications will vary based on their background knowledge. After students answer this question and share their reasoning, show them the video. This video shows shrimp thriving in an EcoSphere 17 months after purchase, and a comment from the EcoSphere owner indicates the shrimp were still "alive and well" 6 years after purchase. After viewing and discussing this second video, have students provide an initial answer to the "Big Question:" Based on your observations of the EcoSphere, how can the shrimp get the matter and energy they need to survive when they are closed within this system?

Surviving Inside the EcoSphere

Initial Sensemaking: Ecosystem Cycles

You can prompt students’ thinking about the movement of matter and energy in ecosystems by using the “Ecosystem Cycles” formative assessment probe from Uncovering Student Ideas in Life Science, Volume 1. (You can learn more about using formative assessment probes by reading the “Why is my shadow always changing?” Daily Do.) These probes are best used in three steps.

  1. Use the probe to activate students’ prior knowledge.
  2. Engage students in experiences during which they acquire evidence and new information.
  3. Have students use what they discovered to revisit, revise, and extend their initial thinking.

Ecosystem Cycles

In this case, students will acquire evidence from the data analysis task.

Share the “Ecosystem Cycles” probe with your students. Read through the probe with students or give them time to read through it. Have students share their initial answers and reasoning. If you are working with multiple students, it might be helpful to have them write down their initial responses before sharing. Prompt students to clarify their thinking, but be careful not to give away the explanation at this point. Ask students to relate their ideas to the shrimp inside the EcoSphere. Then tell them, "We are going to look at some data that will help us figure out how matter and energy move in the EcoSphere."

Analyzing and Interpreting Data: EcoSphere Data Analysis

Direct students to the second page of the "Surviving Inside the EcoSphere" handout, which provides data for four different scenarios. The first scenario includes all the normal components of the EcoSphere, while the remaining three scenarios provide data for systems where one component was not present. The data used in this task are simplified from the original source to make them more accessible to middle school students. The original tasks provide additional data in its full complexity, and the tasks address multiple question about matter and energy transfer and cellular respiration. These tasks are suited for high school students, but it might also benefit middle school students to examine the original data after they make sense of patterns in the simplified data.

Data Analysis Handout

Ask students examine the data carefully and look for patterns that can help them understand and explain how the shrimp obtain the matter and energy they need to survive. Point out to students that the final column in each data table jumps from Day 30 to Day 100, so it represents a longer timespan that the previous columns. You can use the following questions to prompt student thinking, and students may need to obtain information through online research to support their sensemaking.

  • For each water quality factor listed in the first column of the data tables, why it is important to the organisms living in the EcoSphere?
  • What do the numbers in the Acceptable Range column mean? What might happen when values are outside of this range?
  • For each water quality factor, describe any patterns you see in the data for that factor as time passes. Are the values increasing, decreasing, staying the same, or going up and down?
  • For each scenario where a component was removed from the system, why did removing that component lead to the observed changes in the water quality data?

Students should notice the following patterns. These patterns point to roles that each group of organisms plays in the system and to the interactions among living (biotic) and nonliving (abiotic) components of the system.

  • With all components present in the EcoSphere turbidity, oxygen, and carbon dioxide levels fluctuate slightly but remain within acceptable limits over time.
  • When algae are removed from the system, oxygen levels decline well below the acceptable value.
  • When bacteria are removed from the system, turbidity levels increase beyond the acceptable range, oxygen levels increase over time, and carbon dioxide levels seem to be slightly lower than normal.
  • When shrimp are removed from the system, turbidity levels decrease and then stabilize, oxygen levels increase, and carbon dioxide levels remain stable but seem to be slightly lower than normal.

After students analyze the data, revisit the “Ecosystem Cycles” probe. Give students time to reread and respond to the probe. Then have students share their responses and thinking. At this point, you want to press students to use evidence from the data to justify their explanations. If a student is committed to an explanation other than Felicia’s, then press them to revisit the evidence.

The best answer is Felicia’s: “I think only matter cycles through an ecosystem.” Matter and energy both move through an ecosystem. However, only matter cycles back and forth between organisms and the environment; energy moves only in one direction, with much of it being dissipated into the environment as heat. Both matter and energy can be transferred from one organism to another or from an organism to the environment; but only matter cycles within ecosystems, being used in various forms as it moves through food webs, water, soil, and the atmosphere.

Developing a Model and Explanation: How can the shrimp get the matter and energy they need to survive?

Now that students have built knowledge by analyzing the data and possibly conducting online research, you will want to support them in applying this knowledge to answer the guiding question by developing a model of the EcoSphere system and constructing an explanation of how the shrimp get the matter and energy they need to survive. See pages 3 and 4 of the "Surviving Inside the EcoSphere" handout.

Explanation Scaffold

Provide the following guidance to help students develop their model.

  • Show all the important living and nonliving components of the system.
  • Show the source(s) of energy for each group of organisms in the system.
  • Show how both matter and energy move into, out of, and/or within the system. It may be useful to use different colors or symbols to represent the movement of matter and energy.
  • Think back to the "Ecosystem Cycles" probe. Does matter flow through or cycle within the system? Does energy flow through or cycle within the system

If you are working with multiple students, have them compare their models and discuss similarities and differences. Students can then revise their models based on this discussion. Alongside the ecosystem model, students will develop a written explanation that answers the guiding question. Page 4 of the handout provides a scaffold that students can use to organize their thoughts as they develop this explanation.

NSTA Collection of Resources for Today's Daily Do

NSTA has created a How do shrimp live in a closed system? collection of resources to support teachers and families using this task. If you're an NSTA member, you can add this collection to your library by clicking ADD TO MY LIBRARY located near the top of the page (at right in the blue box).

Check Out Previous Daily Dos from NSTA

The NSTA Daily Do is an open educational resource (OER) and can be used by educators and families providing students distance and home science learning. Access the entire collection of NSTA Daily Dos.

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