Presentation on theme: "Water Canaries Assessing Benthic Macroinvertebrates"— Presentation transcript:
1 Water Canaries Assessing Benthic Macroinvertebrates Created by Libby Campbell, BTW Educator, 2003Bridging the Watershed An Outreach Program of the Alice Ferguson Foundation in Partnership with the National Park Service and Area Schools
3 Consider the following when trying to identify an organism
4 Macroinvertebrate Body Characteristics SegmentsWormlike– Isthe abdomenfleshy or havearmored plates?Does it look easilysquishable?Segmented crittersNot wormlikeTiny—in nature, tiny generally means less than a centimeter—test to tell: do you have a hard time seeing anything more than a squiggly line?Large and plump
5 Legs Six true legs plus lateral filaments Six segmented legs Prolegs More than six legs
6 Tails Tail-like projection Featherlike tails No tail or tiny tail Two tails
7 Details to notice: gills Abdominal filamentous gillsAbdominal gillsInternalgills
8 Practice ID Visible Gills? Legs? Number? Length? Placement? Details? Antennae? Eyes? Wings? Tail?
9 DirectionsYou will be shown pictures/drawings of 15 different types of organisms.Each slide will be visible for 2 minutes.Use your worksheet to draw each specimen.Begin with basic body shape and most important details.If there is more than one image on a slide, choose one to draw.Each organism or set of organisms represents one category thatcorresponds to the data sheet you will use in your field study.
16 Specimen 7Damselfly nymph: note three tails that are featherlike, broader than a mayfly tail.
17 Specimen 8Scud: note more than 6 legs, curled, shrimp-like, flattened side to side
18 Specimen 9Net-spinning caddisflies. Note the six legs, three dorsal plates, and filamentous gills on the underside.
19 Specimen 10Crane fly, a True Fly larva. Usually quite large, with tail-like projections.
20 Specimen 11Dragonfly larva: note the tiny three tails and variable body shapes.
21 Specimen 12Beetles. This category is highly variable.
22 Specimen 13Lunged snails, with opening on the left. Flat coiled snails are also lunged snails.
23 Specimen 14Black fly larva. Very small, with bulge at one end where it has a suction cup, with which it attaches itself to rocks, and then waves the projections at the other end to catch food.
24 Specimen 15Fish fly larva. Note the lateral filaments, or “fake” legs. Sometimes very large (up to 4 inches) with sharp biting jaws.
25 End of Drawing Activity Use your drawings and reference materialto identify your organisms.After students have had the opportunity to try to identify their organisms, go back through the specimens to be sure they have identified them correctly.
26 This key corresponds to the categories used on the Tally sheet students will use in the field study.
27 Benthic macroinvertebrates can be classified according to their sensitivity to pollutants.
28 Sensitive Mayfly larvae Stone Fly larvae Most caddisfly larvae Beetles (adults and larvae)
29 Somewhat Sensitive Dragonfly and damselfly larvae Netspinner caddisfly larvaeCrayfishGilled snailsAquatic sowbugsScudsClams and musselsTrue fly larvaeHellgrammites, Fishfly and Alderfly larvae