Exploring Ecosystems

Anthony D. Fredericks

An ecosystem may be as large as the Sonoran desert or as small as that found under a single rock. This month’s column explores the complex relationships of living things to their natural environment and to each other. The activities suggested here will help students appreciate the interrelationships and interdependencies within communities—whether that community is in their own backyard or across the country.

This Month’s Trade Books

Under One Rock: Bugs, Slugs, and Other Ughs
By Anthony D. Fredericks.
Illustrated by Jennifer DiRubbio.
32 pp. Dawn Publications. 2001.
ISBN: 1-58469-028-3 (HB);
1-58469-027-5 (PB)
2002 Ecology and Nature Award
2003 Teacher’s Choice Award

Synopsis

Through this creatively illustrated book, readers can make some amazing discoveries about an ecosystem right in their own backyard. In the story, a boy lifts a rock to reveal a dynamic community of organisms that reside on and in the ground. Using a rhythmic verse based on “The House That Jack Built,” the book introduces the organisms and describes something about their habitat or behaviors (i.e., “This is the spider with her eight-eyed face/Who builds a home in this cool, dark place”).

Around One Cactus: Owls, Bats, and Leaping Rats
By Anthony D. Fredericks.
Illustrated by Jennifer DiRubbio.
32 pp. Dawn Publications. 2003.
ISBN: 1-58469-051-8 (HB);
1-58469-052-6 (PB)

Synopsis

Around One Cactus introduces readers to the Sonoran desert environment. A young boy spends the day watching the happenings that take place in and around a single Saguaro cactus. There’s not much going on at the cactus, so near the end of day, the boy leaves. But, that’s when all the activity begins! Rattlesnakes, elf owls, kangaroo rats, scorpions, and other desert creatures come out to “play and prey” at night. The desert community is an active one—it’s not often seen by visitors, but it’s filled with lots to discover.

Curricular Connections

An ecosystem is a dynamic entity consisting of a group of living organisms (plants, animals, and microorganisms) that interact with one another and with the nonliving environment (air, water, rocks, and energy). To learn about ecosystems is to learn about the relationships of living things to each other and to their natural environment. These complex relationships commonly involve food, shelter, and reproduction.

These books are part of a series that explores the relationships and interdependencies in nature. According to the National Science Education Standards, students in grades K–4 should be developing understandings of the way organisms live in diverse environments and depend on varying resources (NRC 1996). Upper elementary students need to understand that ecology centers both on the various components of nature as well as how the components work together as a whole. Students also need to know that the interactions that take place in a desert ecosystem, for example, share some basic similarities but are also different from those in other ecosystems.

Trade Book–Inspired Investigations

Each book in this series focuses on an individual involved in scientific inquiry. Each main character uses basic scientific processes (e.g., observing, classifying, predicting) to learn about a specific ecological community (e.g., under a rock, around a cactus). The unifying importance of the books is that any young reader can make similar discoveries—in their own backyard, on a day trip, or during a family vacation.

For Grades K–3: Observing Other Worlds

The ideal way for students to make these connections between organisms and their environments is through direct observation of the natural world. Try the suggestion below in concert with Under One Rock: Bugs, Slugs, and Other Ughs to build on your students’ natural curiosity.

Take a field trip or a walk around the school grounds with students, looking for one or more flat rocks. (If there aren’t any suitable rocks, try looking under a log, or pick another “mini-ecosystem” that you can directly observe.) While on your walk, ask students to point out characteristics of the environment, asking such questions as, “Do you see signs of insect activity?” or “Do you see any animal homes?”

When you locate an appropriate rock, ask students what they think might be beneath the rock. Carefully lift the rock and ask students to describe what they see. What does this habitat look like—is it dark, wet, etc.? What types of organisms are hidden there? What do they look like? Where do you think the organisms find food, water? What do you think would happen if the rock were removed, changing the environment? Have students draw and describe some of the organisms they see in a field journal or on paper for later classroom discussion. When students have finished their drawings, carefully replace the rock and continue the walk. Ask, “What other habitats do you observe? How do they differ from the rock habitat?”

Back in the classroom, read Under One Rock: Bugs, Slugs, and Other Ughs. Compare the organisms found under your rock with those in the book. Challenge students to discuss the differences and similarities (physical features, behavior, size) between and among organisms living beneath a rock. They can also list the living and nonliving components of the rock ecosystem.
Encourage each student to select one of the animals from the book. Read aloud or have students individually read the “Field Notes” (at the end of each book) pertaining to their selected creature. Then, ask students to create a sentence or a short story told from the perspective of their selected animal, describing why they chose their habitat and how they interact with other organisms they encounter. You can also collect additional library or Internet resources on the organisms for a classroom display or activity center, further introducing students to the diversity of life found “under one rock.”

For Grades 4–6: Investigating Relationships

Older students are better able to understand the ways populations and communities interact with each other. Students will be fascinated to learn about the adaptations and interrelationships that exist within the community “around one cactus.”
Collect photographs of various mammals, birds, reptiles, insects, and spiders found in a desert (e.g., kangaroo rat, elf owl, long-nose bat, rattlesnake). You will also need pictures of desert plants.

Discuss and/or review the basics of a food chain: Sun—plant—animal—animal, explaining that food webs are a good way to represent many of the complex, overlapping relationships within an ecosystem. For example, predators rely upon more than one type of prey, and plants feed many types of consumers.

Create a chart with two columns: producer (makes its own food) and consumer (eats other plants or animals). (Consumers can be further divided into herbivores, omnivores, and carnivores.)

Next, read Around One Cactus: Owls, Bats, and Leaping Rats, taking note of the relationships between the featured organisms. Discuss with students where desert organisms obtain their food. Which organism are the others most dependent upon? (Plants are primary producers.) As a class, fill in the producer and consumer chart with examples from the photographs you collected.

After reviewing the roles of various desert animals, students can take the members of the desert ecosystem and place them into a food web. Present students with the photographs, including the photographs of plants, and have them tape them on the board (make sure you include the Sun), connecting them with arrows to show the relationships.

Have a blank piece of paper ready for the next part of the discussion: Cover one of the members of the food web at random. Ask students what would happen if this member were eliminated from the food web. Questions should stress the interaction between the different species of the ecosystem, such as, “Which organisms would be affected the most?” and “Which missing factor would have the most effect?”

Discuss how members of the desert community are able to live in the same harsh habitat. For example, some species are nocturnal and burrow into the cool ground to avoid the heat of the day; cacti have spines to prevent animals from eating them to obtain water, but some birds are still able to create their nests in the cacti.) What are some other ways that organisms in this ecosystem need one another?

Using the “Field Notes” at the end the book and additional Internet resources, have students choose a desert animal and create an “activity” time line—describing the animal’s activities, habits, travels, and motions over the course of a day. Afterwards, combine the animals’ time lines to create one time line of desert activity all day long. How are the interdependent relationships of the animals in this ecosystem reflected in the time lines?

As an application, challenge students to create food webs and time lines for animals in different environments, such as the organisms profiled in Under One Rock or one of the other books in this series (see Resources). How are the time lines similar or different?

Also, have students consider their local environment. What do we do that affects the local food web? Mosquitoes are annoying. What animals would be affected if we eradicated them? Activities such as these will help students begin to appreciate the diversity in and among biological communities, even the one in which they live!

Anthony D. Fredericks (afrederi@gte.net) is a professor of education at York College in York, Pennsylvania, and an award-winning children’s book author.

Resources

Fredericks, A.D. 2002. In One Tidepool: Crabs, Snails, and Salty Tails. Nevada City, Calif.: Dawn Publications.
National Research Council (NRC). 1996. National Science Education Standards. Washington, D.C.: National Academy Press.

Internet

How Do Animals Survive the Desert?
www.desertusa.com/animal.html
Nature Study in the Sonoran Desert
arizonensis.org/sonoran/fieldguide/index.html
The Saguaro Cactus
www.nps.gov/sagu/guides/saguarocactus.pdf

Click here for PDF file.