LESSON 2 Activity 2

Buckets of Bugs

Grades:

4th - 7th

Objective:

Students become familiar with several types of the macroinvertebrates they may find in a stream. This activity also shows students how to determine the level of impact that pollution has had on a stream. By looking for certain types of macroinvertebrates, students will be able to decide if a stream is "impacted" or "non-impacted".

Method:

Each group of students will be given a fictitious stream sample on cards. They will identify each specimen and follow a set of screening criteria to analyze their stream's health.

Materials:

Six (or more) plastic sour cream containers (16 oz.), cut-outs of the macroinvertebrates Page 1 and Page 2 cards, copies of the Biological data sheet, and Stonefly picture for each student, overheads (Biological data sheet, Stonefly, Mayfly, and Caddisfly), and crayons.

Time:

Preparation Time: 30 minutes
Class Time: 30-45 minutes

Procedure:
  1. Preparation: Make nine copies of each macroinvertebrate card sheet. Cut out along the lines. Divide up the cards into the different buckets, putting at least 10 in each bucket. We suggest that you purposely create one or two buckets representing non-impacted streams, and at least one group have an extremely impacted stream. This is accomplished by strategically placing certain cards. Non-impacted streams would include: mayflies, stoneflies, caddisflies, water pennies, and hellgrammites. A very impacted stream would consist mostly of aquatic worms. A somewhat impacted sample might have mayflies, stoneflies, and caddisflies along with aquatic worms. Create some of these as well.

    Note: Crayfish and crane fly larva can survive in both impacted and non-impacted water. These can be placed in any containers.

  2. Begin by reviewing the three body segments of an insect, as well as the differences between the mayfly, stonefly, and caddisfly. Hand out the large stonefly drawing. Students will color each segment a different color: head=red, thorax=green, abdomen=blue. Legs, wing pads, antennae, etc. are part of the segment to which they attach and should be colored accordingly. Use the stonefly overhead to point out the three segments.

  3. Explain how the body segments are used for identification: The STONEFLY has gills on its thorax, whereas the MAYFLY has gills on its abdomen. You can't always go by the number of tails; some mayflies have only two. Show the caddisfly overhead and ask a student to point out the thorax. The thorax/abdomen boundary is less clear on the caddisfly, so you need to emphasize that the part with legs is the thorax; everything behind that is the abdomen.

  4. Tell the class that they are going to be given a bucket with specimens collected from a stream. Their job is to sort through the aquatic insects and determine whether their stream is IMPACTED or NON-IMPACTED. Introduce these two terms. IMPACTED means a stream has had some impact from pollution. NON-IMPACTED means that there is no sign of any pollution. These streams have the highest water quality. There are many degrees of how impacted a stream is, from very impacted, to just slightly impacted, to not impacted.

  5. Once the difference between impacted and non-impacted is clear, divide the class into groups of no more than four. The number of groups should equal the number of buckets.

  6. Each student should have a copy of the Biological Data Sheet, and each group should now have a stream sample container. Put up the overhead of the Biological Data Sheet, and have them fill out the upper portion. Explain how to fill out the data sheet based upon their sample, up to the Screening Criteria section. This section will be done as a class.

  7. Instruct the groups to sort and identify the invertebrates. Note that not all cards have names on them, but the students should already be familiar with how to identify those that do not. After they have the types and numbers recorded, they can add up the totals for their group.

  8. When all of the groups are finished and the buckets have been collected, explain the section on the data sheet entitled Screening Criteria For Non-Impacted Streams. This method for classifying streams is used by the Department of Environmental Conservation (DEC).

    Note: Ignore the 3 species of mayflies for this activity. Also, make sure the students understand that they should only check the box that deals with worms if they do not have any. It is the opposite of the other four boxes.

  9. After you have gone through each criterion with the class, ask each group how many boxes they have checked, and what that means in terms of impacted and non-impacted.
Assessment:

  1. What types of macroinvertebrates would we need to find in a stream to classify it as non-impacted? What types would classify it as an impacted stream?

  2. What are some sources of pollution that could impact a stream?

  3. What are some activities you do that could affect what types of macroinvertebrates are living in a stream?

NYS Learning Standards:

Math, Science, and Technology
Standard 1 - Analysis, Inquiry, and Design: Scientific Inquiry 1
Standard 4 - Science: The Living Environment 1,5,7


Source: Activity devloped by Nathan Chronister.