CAM 7th/8th Science | CAM 7 Science

Macroinvertebrates & Water Quality Testing


Unit Review:

  1. What is a watershed?
    (An area of land that drains into a body of water ... East Fork Lewis R., Columbia River, Puget Sound)
  2. Why do we need to monitor the water in streams?
    (determine the health of streams; check of habitat/pollution problems; streams used for habitat, recreation, water & food)
  3. What is pollution? What is non-point pollution?
    (anything that has a harmful effect on the environment; non-point is pollution from numerous sources or locations)
  4. What is the riparian zone?
    (area of land along the stream)
  5. What are some physical parameters measured during stream monitoring?
    (depth, width, flow rate, temperature, turbidity, gradient, substrate, sunlight/canopy cover)
  6. What is canopy cover and why is it important?
    (tree branches extending outward over the stream; blocks sunlight & limits aquatic plant growth, shades & cools the stream, provides organic material in the form of leaves ...)
  7. Why is water temperature important?
    (temperature affects metabolism and growth rate of aquatic organisms; affects amount of DO in the water; excessive heat can kill organisms)
  8. What is turbidity and why is it important?
    (clarity of the stream; measures the amount of solid particles in the water which can block sunlight, reduce visibility & in large amounts can bury eggs and clog gills)
  9. What are some chemical tests done during stream monitoring?
    (dissolved oxygen, pH, phosphate & nitrates, salinity, ...)
  10. What is DO and why is it important?
    (many aquatic organisms use gills to remove oxygen molecules dissolved in the water; without sufficient DO they suffcate; adequate DO is especially important for salmon & sensitive macros)
  11. How does oxygen get into the water?
    (molecules transfer from the air; splashing of the surface by waterfalls & rapids; photosynthesis by plants & algae)
  12. What is pH? (What does it measure?) What is neutral on the pH scale?
    (pH measures the acidity or alkalinity of a substance; 7 is neutral; <7 is acidic; >7 is basic (alkaline)
  13. How do phosphates & nitrates affect streams?
    (chemicals that act as fertilizers promoting plant & algae growth in the stream)
  14. What is biological testing?
    (determining the environmental health of an area using living things ... bugs, plants, birds, fish, ...)
  15. What are benthic macroinvertebrates?
    (organisms without backbones that are large enough to be seen with the unaided eye and live on the bottom of a stream or lake)
  16. What part of a stream do we use for collecting macros? Why?
    (macro samples are collected in riffles; better habitat because of higher oxygen & rocky substrate produces more biodiversity; shallower areas of stream that are safer to sample)
  17. What are three groups (orders) of insects that are indicators of good water quality?
    (E-P-T: mayflies, stoneflies, caddisflies)
  18. What are the three body parts of insects? How many legs do insects usually have?
    (head - thorax - abdomen; insects have six legs -- an exception are the larvae of the true flies (Diptera), such as blackflies, craneflies, midge, ...)
  19. What two life cycles might insects experience? Why don’t larvae lay eggs?
    (1) incomplete: egg, nymph, adult; (2) complete: egg, larva, pupa, adult;
    larvae are the immature forms of the organisms, it's the adults that lay eggs)
  20. What is FFG? What are the four groups? What do they eat? Know some examples for each group.
    1. shredders eat CPOM (leaves, cones, sticks, ...) - brown stoneflies, organic case caddisflies, many craneflies
    2. collecters (filterers & gatherers) eat FPOM (organic matter <1mm) - blackflies, netspinner caddisflies, nussels, mayflies, beetles (except predaceous)
    3. scrapers/grazers eat diatom & algae coating rocks - flathead mayflies, snails, mineral case caddisflies
    4. predators eat other living things - mottled color stoneflies, free-living caddisflies, dragonflies, predaceous beetle larva
  21. Be able to identify the following: (Review macros identification using the "Know Your Macros" slideshow, or test your knowledge with one of the "Macro ID Practice Sets." See other examples at's: Freshwater Macroinvertebrates.)
    • mayfly larva
    • stonefly larva
    • caddisfly larva
    • cranefly larva
    • sowbug
    • scud
    • blackfly larva
    • water boatman
    • water beetle (adult & larva)
    • midge larva
    • water mite
    • crayfish
    • aquatic earthworm
    • flatworm
    • snail (right vs. left)
    • mussel

For information, questions, or comments,
email Michael Clapp:
CAM Academy - Battle Ground Public Schools
Modified : 11/16/15