Living in Leaves
Duration: 30 to 45 minutes
Vocabulary: invertebrate, life cycle, decay, detritus
Summary: Students will gather leaves and create an environment inside the classroom in which the animals that live there can be captured and studied with a dissecting scope.
Objectives: Students will gain a understand that there are many types of habitats, and even something that seems “useless” like a pile of leaves can be important habitats, and many small animals live in these areas.
Materials: collected leaves (stored in bag), large funnel, light, jar filled with ethanol OR dry container, invertebrate I.D. information
Decaying leaves and plant material create an important habitats. It gives both food and shelter to a variety of plants, fungi, invertebrates, and other animals. Bacteria and fungus arrive first and start to break down the plant material. After the bacteria, macroinvertebrates come along to eat the dead plant material. Insects, worms, and fungi break down bigger leave particles and eat the organic matter. Other invertebrates, like millepedes, are present in these leaves because they eat the organisms eating the plant matter. Bigger still, you can sometimes find salamanders and toads living under piles of wet leaves because 1.) there are plenty of insects to eat and 2.) the moisture held in the leaves keeps their skin damp and helps them breath. Finally, birds, snakes, and other small carnivores/insectivores come looking for the larger insects and amphibians. Pretty soon, you have a whole food chain that all started with the plants and nutrients that fall to the forest floor.
Ask students to imagine what forests would look like if nothing ever decomposed. What would happen? What role to decomposers and other small organisms play in our lives?
Explain the basic properties of the food chain to students if they are unfamiliar with it.
Explain to students that they will be interacting with the base of the food chain and doing a collection of the organisms that eat plant matter, and the ones that eat those. Take students to an outside location to collect a pile of damp leaves. Try to get ones that are damp. Bring these leaves back to the classroom and put them in a funnel that goes into a jar. The jar can either be dry, if you would like students to just observe with the naked eye/magnifying glasses and release again, or filled with ethanol if you want students to be able to look at these organisms with a dissecting scope. Put a light over top of the funnel and wait.
As the leaves dry out, the heat from the lamp should drive any living creatures in the leaves down through the funnel and into the jar. Once you have a significant amount of organisms trapped in the jar or preserved in ethanol, have students examine the invertebrates that they captured. Have students record how many there are total, as well as how many are different kinds. If possible, have them examine the organisms with a dissecting scope and identify as much as possible.
If the insects were not preserved in ethanol, take the class to release them and return the pile of leaves to the location where you found it. Have students then pick a different organism found and research what they do and how they are a beneficial part of the ecosystem.
Ask students to explain the food chain, and give an example. Ask students to explain whether they think the organism found in the leaves are important and why. Also have students share what they learned about their individual organism with the class.
Have students gather leaves from different types of locations, like in a forest, beside a stream, or in a field and compare what kinds of invertebrates are living in each type.