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MICRO-ECOSYSTEMS

by Nora C. Doerder


Type of entry:

  • Long term project

Type of Activity:

  • hands-on
  • Authentic assessment
  • group/cooperative learning
  • off-site
  • review/reinforcement

Target Audience:

  • Biology
  • Advanced/AP biology
  • Environmental studies
  • Special needs

Background Information

The Micro-ecosystem activity/project can be used during an ecology unit and can be adapted to a variety of classes and students.It is best to set up the ecosystems early in the school year and to construct them following a field trip. A pond or wetland can provide good sources of "starter" mud and water. Students design an aquatic or terrestrial micro-ecosystem or model local ecosystems in 10 gallon aquarium tanks.

The project may take from one to three weeks depending on the amount of time available for lab and how involved the project becomes. Observations on the micro-ecosystems occur over the school year, and the tanks are left until fall for initial study by a new class. Opening the micro-ecosystems provides materials for labs that may include: doing a biological survey utilizing dichotomous keys, reviewing/studying the five kingdoms, practicing basic microscope techniques, creating microbiological cultures or Winogradski columns. The organisms and materials from the previous year's projects are recycled in the new projects. The micro-ecosystems also include time capsules.

The tanks should be near windows but generally do best with lower levels of light (less chance for a green house effect to cook the interior). The outside designs that students paint also help control light levels. It is possible to stack the tanks with boards and cement blocks or on aquarium stands.


ABSTRACT

This project focuses on the challenge of creating a sustainable, self-contained ecosystem in a ten-gallon aquarium. Students first study the mocro-ecosystems from the previous year's classes. Groups are assigned complete clean-up and cataloging of the available resources. They must propose a design for their own micro-ecosystems and justify their design in terms of matter and energy requirements, trophic levels and population interactions. The tanks are painted with creative biological/environmental designs, and students participate in sealing ceremonies that include a class presentation, a visual interpretation of the structure and functioning of their ecosystem and a written report. Students continue to make observations on the ecosystems during the year.


Lesson/Activity

Materials needed:

  • For Micro-ecosystems:
    • 10 gallon aquarium (1 per 4-5 students)
    • Glass piece cut to fit the top of the tank (ask your building custodian)
    • Duct tape for sealing the lids on the tanks
    • Gravel, sand and rocks
    • Soil (ask your students)
    • Seeds - collect local or purchase seeds - small plants work best
    • Local plants - mosses, ferns, small herbaceous plants
    • Pond samples - plants, water and pond bottom
    • Possible animals - snails, pillbugs, earthworms, minnows
    • Snap-top disposable test tubes

  • For decorating the tanks:
    • Acrylic paints
    • Tempera paint mixed with liquid acrylic polymer (This adheres well and is easy to clean off glass)
    • Assorted brushes (talk to an art teacher)


Student guidelines/worksheet

MICRO-ECOSYSTEMS

Purpose
The purpose of this project is the construction of functional micro-ecosystems that model naturally occurring ecosystems. The underlying principles of the structure and function of ecosystems will be studied and explored in class. The creation of micro-ecosystems will provide you with the opportunity to apply your understanding of these concepts. Ecosystems involve the interaction of biotic and abiotic factors and the establishment of complex relationships between organisms and their environment over long periods of time. Ideally the micro-ecosystems should mimic what occurs I natural systems and should also reach a state of equilibrium or stability at some point.

Groups of 4-5 students will work on a single ecosystem. Study of the micro-ecosystems will occur for the rest of the school year. The micro-ecosystem is limited by the sze of the container and the sealing of the tank so that only sunlight may enter. Careful planning by the group will help in the creation of a functional exosystem. Continuing observations of your ecosystem during the year will enable you to see how well your design actually functions.

PROCEDURES

1. A 10 gallon aquarium will be assigned to your group. The tank will be completely sealed from the outside environment. You can choose to develop any type of ecosystem within the limitations of a 10 gallon tank.

2. Utilize the textbook and any of the class reference books to determine what types of components to consider for your specific ecosystem.

3. Carefully plan the ecosystem with regard to the following: matter and energy requirements, trophic levels and size of populations. Think about the equilibrium which should be established eventually. A plan must be approved before actual construction of the ecosystem begins.

4. Available materials from previous tanks or field trips and any purchased materials will be cataloged in class. Any other materials you decide upon must be provided by your group.

5. Along with considering the internal components of your ecosystem, consider the external container to be a place to make some creative statement about yourecosystem and the study of biology/ecology in particular. Create a design, painting, poem, or statement which reflects your feelings about the unique ecosystem you have designed. Be careful that the design does not disrupt the flow of energy into your ecosystem.

6. Plan an appropriate message for next years students to be placed in a time capsule in the micro-ecosystem.

7.ACTUAL WORK ON ECOSYSTEMS SHOULD BE COMPLETED BY____________________________.
The micro--ecosystems will be temporarily sealed and observed for several days before final sealing. This will allow you to make an "adjustments" if necessary.

Sealing the lids onto the tanks with duct tape wil be performed in class________.

Nothing but sunlight can enter or leave your eosystem after sealing.

8. SEALING CEREMONIES: At the time of sealing, you will be asked to make a short informal presentation of your ecosystem to the class. This presentation should include a description of the nature of your ecosystem as well as any other creative efforts you wish to use to mark the sealing of your system. Each member of the group must participate in the ceremonies.

9. Remember to include each team member's initials and the sealing date somewhere on the ecosystems.

OBSERVATIONS

Written observations of hte conditioons in your ecosystems and the change and interactins between the living things will be continuous and on-going over the course of the year. Try to explain most of the changes that you observe and draw some tentative conclusions concerning the stability of your ecosystem.

ASSESSMENT:

WRITTEN SUMMARY (from group) Due___________________

1. Diagrams/drawings of your micro-ecosystem with the components of your ecosystem clearly labeled for

A. ECOSYSTEM STRUCTURE (Abiotic and biotic parts): Identify all LIVING AND NON-LIVING PARTS of the micro-ecosystem.

B. ECOSYSTEM FUNCTION (matter cycles and energy flow): In a single diagram/drawing (8 1/2 x 11) include the following cycles (color-coded) WATER in BLUE, CARBON in BLACK, OXYGEN in RED, NITROGEN in GREEN. Also indicate ENERGY FLOW in YELLOW.

2. A written prediction (minimum 1 page) for the future of your ecosystem in terms of the processes that you expect to occur. How will your system change through the seasons? What kind of stability can you predict for your micro-ecosystem? How long will this take (1 month? 3 months? 1 year?)


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