Worm Watch

Lindsey Molstad-Duluth Public Schools
Information gathered from Minnesota Department of Natural Resources and Great Lakes Worm Watch
Author Profile

Summary

In this biology field lab, student investigate the types of worms found in the school area. To determine worm species present students will use the flip and strip, midden counting, and liquid extraction sampling methods and then bring them back to the lab to identify.

Used this activity? Share your experiences and modifications

Learning Goals

This activity is designed to:


1) Explain the ecological role of earthworms
2) Identify the type of earthworm species found in the sample area
3) Learn scientific earthworm sampling techniques


Higher order thinking skills:
Observation of samples, identification of worm ecological groups, practice setting up sample areas using measurement tools, and data analysis.

Vocabulary:
-Clitellum
-Setae
-Midden

Context for Use

I present the worm watch lab during a unit on worms. Typically, I start out with an introduction of external and internal anatomy, structure, and function. Students draw and label the worm. Following the drawing, I have the students dissect an earthworm to practice beginning dissection skills and to further identify internal anatomy. The worm watch lab works best in a school yard that has a hardwood forest on or near the property. Usually the lab takes one class (55 minutes) to do the midden count and flip and strip method and a second class (55 minutes) to set up and complete the liquid extraction. If you want to complete this lab by having the students identify the worms collected that will take an additional class (55 minutes) to identify and discuss types of species, and density of populations. This lab works best when ground is slightly moist-not dry. This lab does require mustard seed powder which should be bought in bulk through a food coop rather than a typical grocery store.

Description and Teaching Materials

Lesson Introduction:
Students are previously given an overview of worms, worm anatomy, and have done a worm dissection activity. I go through the Power Point presentation to describe the ecological implications of earthworms, describe earthworm sampling techniques, and provide an overview of the field experiment.
Materials:
A hardwood forest is used for this activity or a school yard with hardwood trees.
Liquid Extraction Sampling Materials:
- Mustard powder (1/3rd cup/per group)
- Gallon jugs (1 per group)
- Funnels
- 1/3 measuring cup
I also have students use a measuring tape, string, and vegetable stakes to mark out their sampling area for the liquid extraction method and to measure out their midden counting area. Sampling area is determined as a class.
Procedure:

Use three sampling methods; flip and strip, midden counting, and liquid extraction to determine types of earthworms and the density of earthworms that are found in the school yard. Once worms are collected they are identified as anecic, epigenic, or endogenic.


Closing/Wrap-Up:
Students will document their findings on a lab sheet and information will be shared with the class to determine which species were found, how many of each ecological group was found, and to discuss which sampling methods were most useful in collecting individual ecological groups. To expand this lab further, worms could be collected and sent in to the Great Lakes Worm Watch research project.
More information can be found at:
http://www.nrri.umn.edu/worms/default.htm Worm Watch (PowerPoint 27kB Sep9 08) Identification Tips (Acrobat (PDF) 112kB Sep9 08) General Identification Chart (Acrobat (PDF) 1.4MB Sep9 08) Earthworm Population Data Sheet (Microsoft Word 32kB Sep9 08)

Teaching Notes and Tips

I generally only have students identify worms at the level of anecic, epigenic, and endogenic. The Canadian Worm Watch website has a classification chart that is more in depth. Another useful website would be the Great Lakes Worm Watch page http://www.nrri.umn.edu/worms/default.htm
Many students express a dislike for touching the worms, usually they get over this in their excitement to collect worms and have more then a neighboring group. Forceps can also be used to collect worms. I also stress the need for only collecting worms in the sampling area so data is relavent.

Assessment

Assessment #1- Labeled anatomy of earthworm
Assessment #2- Lab Dissection worksheet
Assessment #3- Students participate and actively collect earthworm data during lab. Students turn in a lab data sheet.

Standards

Minnesota Academic Science Standards covered:
9-12 IV. Life Science C: Interdependence of Life
4. The student will predict and analyze how a change in an ecosystem, resulting from natural causes, changes in climate, human activity or introduction of invasive species, can affect both the number of organisms in a population and the biodiversity of species in the ecosystem.

9-12 Life Science B. Diversity of Organisms
1. Learning about structure of Earthworm
3. Classification of Earthworms

9-12 History and Nature of Science - Scientific Inquiry
1. Students will design a scientific study to sample earthworms in the school yard.

References and Resources