Sherri

Sherri S. Breland Bogalusa High School 100 M.J. Israel Drive P.O. Box 580 Bogalusa, LA 70427 MAINTAINING A BALANCED AQUARIUM OVERVIEW
When living things interact, each organism contributes its own special properties to another. These organisms work together to benefit the environment in which they are a part of. Using this experiment, we will see how homeostasis can be achieved in an aquarium.

EXPECTED OUTCOMES
The students should be able to determine if homeostasis has been established in the aquarium.

BACKGROUND INFORMATION
Students need some background understanding of invertebrate and vertebrate animal interactions within the nine Phyla. Students need to have knowledge of graphing. Teachers need TI-83 calculator and CBL unit with pH probes and dissolved oxygen probes. (NOTE: If CBL and probes are not available, this lesson can still be used to show how animals interact together in the aquarium.)

TIME FRAME
Depending on depth of study of this experiment, this lesson could can be done in one day or expanded over any length of time at teacher's discretion.

MATERIALS
    Large glass jar with lid or small aquarium
    Clean gravel
    Aged tap water
    4-5 guppies
    2-3 snails
    1-2 water plants
    If available:
    TI-83 calculator
    CBL with pH and dissolved oxygen probes
    Overhead projector and screen
    LCD panel

PROCEDURE
    Either teacher or students will set up aquarium and place near window where it will receive indirect light. Teacher will give demonstrated lecture of a balanced aquarium and give students a list of questions to answer. Teachers may want to assign groups to discuss list of questions about aquarium. (SEE BELOW)
    After initial set-up of aquarium and students understand concept of the interaction, they may use the pH probes and dissolved oxygen probes to record data and graph. This can be done over period of time allotted by the teacher. At the end of the allotted time, the students can compare graphs to determine if homeostasis has been established and maintained.
    This lesson could be expanded to show students how to make proper adjustments to the pH level or oxygen level in order to maintain homeostasis.

SAMPLE QUESTIONS ABOUT AQUARIUM
    1. What do snails use for food?
    2. Why are plants important to this environment?
    3. What do fish provide to the environment?
    4. Describe the interaction of the plants, guppies and snails
    5. Why is indirect sunlight important?