Stream invertebrates

Background for Teachers

What is in the stream macroinvertebrate community? What do stream macroinvertebrates eat and how do they survive? Do culverts affect macroinvertebrate communities?  In order to develop more specific questions, and hypotheses, about that question your students will need to know about stream macroinvertebrates. This activity is an introduction to stream macroinvertebrates.

In this activity your students:

  • Become resident experts on one or two particular types of stream invertebrate
  • Present their information to the class and
  • Create a class stream foodweb

After becoming the resident expert on one or two types of organisms your students need to recognize that different macroinvertebrates have different environmental needs and that there are different feeding strategies from organism to organism.

See Unit 1, Activity 1: An Introduction to Stream Ecology for an overview of macroinvertebrates.

How your students present the information about their macroinvertebrates is up to you and them, we have provided a template for a two-slide presentation, you may want to use the information requested on the template as guidance for what your students will add to their final product.


    Students will understand the basics of stream foodwebs and know some of the organisms in an aquatic foodweb


  • Students research one or two aquatic organisms
  • Students can identify the four major functional feeding groups of aquatic macroinvertebrates
  • Students, in pairs, will research and report on one or two aquatic organisms
  • Working together students will create a model aquatic foodweb
  • Students will develop questions about aquatic invertebrates or foodwebs

Where does this lesson happen in the Project?

  • This is the first activity in Unit 2- Stream Invertebrates Culverts, and the Stream Environment.

Getting Ready

Some students may already be familiar with aquatic organisms. Solicit information that students already have. If students have experiences with collecting particular macroinvertebrates ask them to describe where they found the macroinvertebrates (small stream or large, water warm or cold? green stuff growing on the rocks? organism right on top, or did they have to flip over rocks to find it? murky bottom? rocky bottom?).

Remind students that macroinvertebrates do not have backbones, and that not having a backbone allows these organisms to arrange their bodies sometimes very differently than land organisms.



    Student Resident Expert worksheet
    Questions worksheet
    Presentation template

Student Prerequisites

Students should:

  • Already have an understanding of a basic foodweb
  • Know the difference between a foodweb and a food chain
  • Understand that all the energy comes from the sun, but that material animals need for survival, growth and reproduction comes from eating other organisms (dead or alive; plant, animal, a combination or other)

Time needed

  • Two class periods

Doing the Activity

Hand Resident Expert worksheet out to students and have them select the organisms they would like to research.

After pairing the students get them started on their research. The research should take approximately 45 minutes. Encourage students to use the paper Macroinvertebrate Guides as this may save time spent on potentially fruitless Internet searches.

Have the students present their invertebrate information to the class.

If you are using the Presentation Template there are two slides for every organism. (Presentations should be very brief—no more than 5 minutes per organism).

Using a picture (from the Resident Experts) for each organism create a stream foodweb to add to the stream system diagram from Unit 1.

If possible leave time at the end of this activity for students to record questions they have.



Ask a question; design a way to answer the question.

Using the Question Worksheet, ask students, individually, or in groups, to write down as many questions as they have about macroinvertebrates (individual species, interactions, competition, food preferences, habitat preference, etc.). From the list of questions have the students choose one or two. Ask the students to design a method to answer the question.  If there is time- present some of the questions and designs and discuss the merit of the research design.

Ask your students to present their Resident Expert information to their families or another class.

Lesson Extensions and Supplements

Watch Macroinvertebrate Lunch:

With teacher’s guide ( Middle school students in Missouri made this movie in 2003. It’s a great movie, however, the focus is on using macroinvertebrates as pollution indicators- and as this it not the focus of our research this resource is better as a supplement.

There is a pollution-related game -- The Macroinvertebrate Game -- which involves a lot of running around!

Lesson Resources

    Student Resident Expert Worksheet
    Presentation template
    Question Worksheet
    Family-Level Identification Guide for Riffle-Dwelling Macroinvertebrates of Connecticut (Note: although this is a guide for Connecticut it is still a good introduction to macroinvertebrates and has information your students will need to become Resident Experts on their macroinvertebrate)
    General background information on macroinvertebrates

application/pdf iconResident Expert Worksheet
application/ iconPresentation template
application/pgp-keys iconPresentation template
application/pdf iconQuestion Worksheet
application/pdf iconMacroinvertebrate Guide
application/pdf iconGeneral background information on macroinvertebrates