Which group of macroinvertebrates might you find in a stream with good water quality?

A. caddis fly larva, mayfly larva, and dragonfly larva
B. damselfly, stonefly larva, and damselfly larva
C. rat-tailed maggot, midge larva, and dragonfly nymphs
D. maggots, rat-tailed maggots, and snails

In the space below, explain how scientists use macroinvertebrate populations to monitor the health of an aquatic ecosystem.

In the space below, explain why just looking at a stream does not always reveal its water quality.

Benchmarks: Grades 3-5 — SC.G.1.2.7, SC.G.2.2.1, SC.G.2.2.3; Grades 6-8 — SC.D.2.3.2, SC.F.1.3.7, SC.G.1.3.2, SC.G.2.3.3, SC.G.2.3.4

Difficulty Level: Grades 3-5 — Hard; Grades 6-8 — Medium

Macroinvertebrates are mostly insects. They also include worms, shrimp, clams, and crawfish. They don’t have skeletons on the inside. Some macroinvertebrates are very picky about living in good quality water. If picky macroinvertebrates are living in a stream or wetlands, then the water quality must be pretty good. If only the non-picky macroinvertebrates are living in the stream or wetlands, then the water quality probably isn’t as good. Sometimes picky macroinvertebrates just go away, and sometimes they die if the water quality is bad enough. When scientists count the numbers and different kinds of macroinvertebrates over and over, they can make predictions about what’s happening to the ecosystem in which the stream or wetlands occurs.

2-Point Response

1. The student demonstrates an understanding that water quality influences the presence and/or numbers of macroinvertebrates living in an aquatic environment.
2. The student demonstrates an understanding that macroinvertebrate populations are indicators of general ecosystem health.

1-Point Response

1. The student demonstrates an understanding that water quality influences the presence and/or numbers of macroinvertebrates living in an aquatic environment.

OR

1. The student demonstrates an understanding that macroinvertebrate populations are indicators of general ecosystem health.

Benchmarks: Grades 3-5 — SC.G.1.2.2, SC.G.1.2.7, SC.G.2.2.1, SC.G.2.2.3; Grades 6-8 — SC.D.2.3.2, SC.F.1.3.7, SC.G.1.3.2, SC.G.2.3.3, SC.G.2.3.4

Difficulty Level: Grades 3-5 — Medium; Grades 6-8 — Easy

Some things in a stream, like oxygen, can’t be seen with your eyes. You have to run a special test to see how much oxygen is in stream water. Other things you can’t see with your eyes are fertilizers, germs, and wastewater from sewer plants. Even the number of macroinvertebrates doesn’t always tell how good stream water is. You have to actually look at them and see what kind they are. Some macroinvertebrates can live in really yucky water. Other macroinvertebrates need the best quality water. If you find the ones that like really good water, then the water is probably really good quality. Sometimes how water looks can be misleading. It’s sort of like the saying, “You can’t judge a book by its cover.”

4-Point Response

1. The student demonstrates an understanding that constituents not visible to the naked eye can impact water quality.
2. The student demonstrates an understanding that specialized testing is necessary to indicate the presence and measure amounts of some water components.
3. The student demonstrates an understanding that other ecosystem components, such as macroinvertebrates, can indicate the quality of water in an aquatic ecosystem.
4. The student provides specific examples to support his or her points.

3-Point Response

1. The student demonstrates an understanding that constituents not visible to the naked eye can impact water quality.
2. The student demonstrates an understanding that other ecosystem components, such as macroinvertebrates, can indicate the quality of water in an aquatic ecosystem.
3. The student provides specific examples to support his or her points.

2-Point Response

1. The student demonstrates an understanding that constituents not visible to the naked eye can impact water quality.
2. The student demonstrates an understanding that other ecosystem components, such as macroinvertebrates, can indicate the quality of water in an aquatic ecosystem.

OR

1. The student demonstrates an understanding that constituents not visible to the naked eye can impact water quality.
2. The student provides specific examples to support his or her points.

OR

1. The student demonstrates an understanding that other ecosystem components, such as macroinvertebrates, can indicate the quality of water in an aquatic ecosystem.
2. The student provides specific examples to support his or her points.

1-Point Response

1. The student demonstrates an understanding that constituents not visible to the naked eye can impact water quality.

OR

1. The student demonstrates an understanding that other ecosystem components, such as macroinvertebrates, can indicate the quality of water in an aquatic ecosystem.

Benchmarks: Grades 3-5 — SC.G.1.2.2, SC.G.1.2.7, SC.G.2.2.1, SC.G.2.2.3, SC.H.1.2.2, SC.H.2.2.1, SC.H.3.2.2, SC.H.3.2.4, MA.B.2.2.1, MA.B.4.2.2, MA.E.3.2.2; Grades 6-8 — SC.F.1.3.7, SC.G.1.3.2, SC.G.2.3.3, SC.H.1.3.5, SC.H.2.3.1, MA.B.2.3.1, MA.B.4.3.2, MA.E.3.3.1

Difficulty Level: Grades 3-5 — Hard; Grades 6-8 — Medium