Litter "Critters" (FBCEC)

Summary:

Participants will collect leaf litter and discover what life exists there. They will discover how these organisms help in the decaying process and how it adds nutrients to the soil. They will identify the different organisms they find and observe their habits.

Grade Level:

4 - 8

Recommended Setting:

Indoor and outdoor classrooms

Outdoor Activity:

No

Location:

Fred Berry Conservation Education Center, Yellville, AR

Contact:

Education Program Coordinator, 870-449-3484

 

Duration:

45 minutes - 1.5 hours

Suggested Number of Participants:

Up to 20

Special Conditions:

Weather permitting.

Objectives:

  • Identify samples of organisms found in leaf litter.
  • Describe the importance of the organisms to the decaying process and how the products of the organisms enrich the soil.

Key Terms*:

Berlese funnel

Decomposer

Humus

Larva

Leaf litter

Soil

*See glossary for definations

Materials:

Berlese funnels

“Crickwing” by Janell Cannon

Empty 6 oz. can cylinders

Magnifying glasses

Rulers

Small hand trowels

Stakes and string

Stereomicroscope

Tweezers or small paint brushes to move the organisms

White paper

Ziploc bags

 

 

 

Background:

A sample of leaf litter is abundant with tiny living organisms such as bacteria, larvae, centipedes, mites and insects which act as decomposers, breaking down leaves and organic matter. The life processes of these “litter critters” results in a soil rich in humus.

Procedure:

  1. Give each participant a trowel, two Ziploc bags, a can cylinder, a ruler and four stakes with string. Tell them they will be collecting leaf litter, but make sure they understand what leaf litter is. Have them predict what they will find in the litter.
  2. Participants will go to two sites. Half the group will collect samples at site one and the other half will collect at site two. Have each group measure and mark off a 10-centimeter square. Next, they should push the can 5 centimeters into the soil within the square to collect a sample. Label this sample “core.”
  3. With the trowel, collect a similar amount of litter from the square and place it in the second bag, labeling it “litter.”
  4. Tell half the participants to place their core sample in a Berlese funnel and have the other half put their litter samples in a funnel. Leave the funnels alone while participants turn their attention to their other sample.
  5. All remaining samples are to be poured onto sheets of white paper. Use forceps or paint brushes to sort through the “litter critters.” Use hand lenses and dissecting microscopes to zoom in.
  6. Give the participants a picture key and an identification sheet that will help identify the animals they find.
  7. The participants can sort the organisms into groups and record in tables and graphs the type and number of organisms revealed.
  8. Finally, repeat the sorting and identification steps for the Berlese funnel samples.
  9. Count and discuss the animals found, even the smallest. Emphasize the role they play in making and enriching the soil. What eventually happens to the leaf litter? Will it always be in the same state they found it in? What would happen if the organisms that eat and live in the leaf litter disappeared?

Modifications:

Younger participants can collect leaf litter and use the funnel as well. They can sort the animals they find in a less detailed way. It is usually easy to find beetles, worms and pill bugs in the litter. The participants can choose one of the organisms they found and make one with construction paper and crayons. These can be cut out and placed on a graph titled “My Favorite Litter Critter.” The lesson can also include stories such as “A Pill Bug’s Life” or “An Earthworm’s Life” by Jim Himmelman.

Review:

  • Explain the role of decomposers in decay and soil formation.
  • Name some “critters” found in leaf litter.

Resources:

  • Fredericks, Anthony D. (2001). Under One Rock, Dawn Publications.
  • Lavies, Bianca (1993). Compost Critters, Dutton Children’s Books.
  • Silverstein, Alvin and Virginia (1972). Life in a Bucket of Soil, Dover Publications, Inc.

Glossary:

Berlese funnel – A device in which soil is placed while heat and light are applied from above, forcing mites, collembolans and other soil organisms into a container below

Decomposer – an organism that breaks down large chemicals from dead organisms into small chemicals and returns important materials to the soil and water

Humus – dark organic part of soil formed from decaying plants and animals, often called topsoil, which improves the soil’s fertility and water-holding ability

Larva – the immature form of an animal that looks very different from the adult

Leaf litter – a combined mix of soil, decaying leaves, compost material and micro critters

Soil – the upper layer of earth that may be dug or plowed and in which plants can grow