water bugs

Evaluating Our Water Biodiversity (t)

In this activity students analyze, identify, and categorize the organisms from the samples collected in the previous activity, Sampling for Water Biodiversity. Just as different sampling techniques were used to collect different types of organisms, there are also distinct methods of analysis for each type of sample. Groups of students will view microorganisms, categorize aquatic plants and macroinvertebrates, and count fecal coliform and other bacteria colonies. For each class of organisms—including the insects and animals observed during field work—students will determine a biodiversity index.

Materials

Water Biodiversity Lab Work
tweezers or forceps
team sheets
glass slides and cover slips
Water Biodiversity Lab Work
compound microscopes
data sheet
hand lenses
How to Use a Compound Microscope
small, clean glass jars
local field guides
protective gloves
pipettes (or eyedroppers)
3- x 5-inch index cards protective goggles
color pencils or crayons (optional)shallow white trays (cafeteria trays are ideal)
GL Journals

Activity-at-a-Glance

* Students use microscopes, magnifying lenses, and local field guides to observe and categorize organisms.
*Students compile biodiversity data for the different types of organisms found in their body of water.

Classroom Management and Preparation

Collect local field guides to help identify your aquatic plants and macroinvertebrate populations. Local libraries and often, local wildlife, fish, and game departments or water management organizations will have such guides. If not, students will still be able to categorize their findings according to shape, color, identifiable features, etc.

This laboratory activity can be done by the same student teams that worked together during the field trip.

Depending on your students’ experience, you may want to demonstrate creating slides and using the microscope. The Microscope Hints teacher background sheet provides additional ideas to support this activity.

Student Preparation Reading

Water Biodiversity Lab Work team sheets

How to Use a Compound Microscope

Recommended Procedures

1. Student teams begin their lab work and describe their findings in their journals.
The laboratory procedures are described in Water Biodiversity Lab Work team sheets. You may also want to remind students to fill in their classification index cards carefully since they will be used to complete a food web later.
Encourage students to write down all observations, thoughts, and ideas in their journals. Encourage them to “think aloud” in their writing. They will need this information when creating a food web. Tell the students they should ask one another for help if necessary. This should be a collaboration between teams, not a competition, especially because they are looking at samples from the same body of water.

2. Have students share their data with any partner teams.

Homework

Ask them: Why do you suppose the biodiversity as great or as small as it is in your body of water? How sure are you of your answer?

Remind students that they do not need to be artists to participate in this activity and should not spend too much time perfecting any one drawing. The idea is simply to have visual representations of what they see. You may also want to remind students of the importance of following protocols and creating accurate records of their work.

Extensions

1. Students can use more advanced field guides and microbiology textbooks to classify and identify the organisms. They can begin their local field guide.
2. Have students calculate a biodiversity index for their samples. They will need access to the lists their team created documenting the species and number of individuals in their samples.
3. Students can do further research on biodiversity indices and form a more sophisticated index of their body of water.

Assessment

Students’ ability to cooperate and work efficiently in the lab should be quite strong by now. You may want to make a formal assessment of these skills during this activity using an observation checklist.

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