Stream Study: An Investigation of an Aquatic Ecosystem

This activity is designed for students to:
1. Develop scientific explanations
2. Undertake a scientific investigation
3. Recognize that variables may influence results.
Some higher order thinking skills involved are those of collecting and analyzing data, developing scientific thinking, summarizing findings, comparing data and explaining results.
The sills developed include: observation, oral presentations, field techniques and equipment use.
Key concepts:
1. Scientific investigations involve a testable hypothesis.
2. Ecosystems are dependent upon the interactions that occur within them.
3. The biotic and abiotic factors of an ecosystem determine which populations that exist within that ecosystem.
Vocabulary:
-Testable hypothesis
-Variable
-Ecosystem
-Population
-Biotic factor
-Abiotic factor
-Interdependency

Grade level: 7 and up
Class size: approximately 30 or less
Institution: School and nearby stream
Field Study
Time required: 40 minutes or more

Special Equipment:
-Water test kits
-D nets for macro invertebrates
-Turbidity tube
-Tape measure
-Meter sticks
-Stop watch
-Thermometer
-Insect nets
-ID keys
-Field notebooks

Skills or concepts needed:
1. Drawing skills
2. Protocol procedures for students
3. Observational skills
4. Wonder

This activity is at the beginning and end of the school year. (Fall and Spring)
Adapting this to other surroundings might be difficult- it is more specific to streams.

My 7th grade students will visit a nearby stream for 9 weeks (weather dependent) to conduct field studies based upon their choice of study. The studies include: Chemists, (ph, phosphates, nitrates, dissolved oxygen) temperature and turbidity, rate of flow, width and depth, macro invertebrates, terrestrial insects, terrestrial plants and plankton. They will be shown an image of the area (from GoogleEarth) they will be going to and told they are going to visit this area in the fall and the following spring. They will get to choose their mode of investigation for this stream after being given a brief description of the different investigations. All areas of study mentioned above will be conducted. Complete protocols will be distributed after the investigations are chosen. Group size will be 3 at maximum and 2 at minimum. The materials for the investigations will be determined by the group's choice of investigation and what is needed based upon their protocols. All protocols will be discussed in the classroom. The groups will generate an investigation based upon their area of study. Their investigation will be correlated with another group's investigation. The groups will write a scientific procedure to be investigated at the stream after the first trip to the stream. The first trip to the stream will be observational and preliminary in nature so that students can become somewhat comfortable conducting their investigations. The students will receive the data from their associate group each week. At the end of the 9 week period students will present their findings to the class noting particularly if a correlation exists between their area of study and their associates. Grading will be based upon a rubric developed by the instructor. This activity is adapted from the Bell Museums "Rivers" program from about 10 years ago.

You might need to get a bus driver's license and permission from your transportation director if a stream isn't close to you school. The first few weeks of this activity are hectic because students like to play before they actually collect data. In the past we never try to correlate our findings with each other in order to talk about the ecosystem as a whole.

Students will be assessed individually for:
1. Data from the stream
2. Contributions to their group
3. Lab notes for me
Collectively as a group for:
1. Presentation to the entire class
2. Experiment they propose to the class and defense of this experiment.

I. History and Nature of Science
B. Scientific Inquiry
1. The student will formulate a testable hypothesis based upon prior knowledge.
2. The student will recognize that a variable is a condition that may influence the outcome of an investigation and know the importance of manipulating one variable at a time.
3. The student will write a specific step by step procedure for a scientific investigation.
IV. Life Science
C. Interdependence of Life
2. The student will define a population as all individuals of a species that exist together at a given place and time.
3. The student will define an ecosystem as all populations living together and the physical factors with which they interact.
4. The student will explain the factors that affect the number and types of organisms an ecosystem can support, including available resources, abiotic and biotic factors and disease.