Lesson Three: The Wetland Foodchain

Title of Lesson: The Wetland Foodchain

Subject(s): Science, Math

Grades: K-4

Teacher(s): Susan Kusunoki, Hedy Kaneoka

I. Stardards Addressed through the lesson:

Domain II: Organisms and Development

Content Standard: Interdependence

• Students describe, analyze and give examples of how organisms are dependent on one anoher and their environments.

II. Goals of the Lesson: (How is this lesson a specific way for students to address the more general standards?)

Students will explore the feeding relationships of wetland animals and identify their interconnectedness in a food web.

III. Content: (Content standards,, background knowledge)

• Students describe, analyze and give examples of how organisms are dependent on one anoher and their environments.

Background information:

Wetlands are many different things to many different people. Some people have never heard of or thought about wetlands, while others are working actively to protect wetlands because of their importance to water quality and as habitat. Wetlands include saltwater marshes, wet meadows, swamps, and alpine bogs.

Wetlands have traditionally been misunderstood and regarded as wastelands, partly because of their inaccessibility to people and their perceived lack of economic value. Indeed the imagery created by many cultures exemplifies how people have traditionally shunned wetlands. The Creature from the Black Lagoon and the Swamp Thing feed on a belief of wetlands as bad places. Slang in the English language reinforces negative images of wetlands: when stressed we get "bogged down" or "swamped" with work.

Yet, wetlands are among the most important ecosystems on Earth, serving as "kidneys of the landscape" for their complex role in regulating hydrologic flows in the watershed and in purifying water. As "biological wonderlands", wetlands are the nurseries of hundreds of life forms, both on land and in the sea. Located at the boundaries of two vastly different ecosystems, terrestrial and aquatic, wetlands are home to a huge diversity of organisms unlike their dry land or aquatic neighbors. Wetlands truly are uniquely important to plants, animals, humans and the entire environment.

Because of the abundance of food, vegetative cover (shelter) and water found there, most wetlands are rich in diverse wildlife species. Coastal and inland marshes, for example, provide breeding, resting and wintering habitats for thousands of migratory birds - including ducks, geese, cranes and shore birds. Many species of fish that are important commercially spend part, or all of their life cycle in fertile wetlands adjacent to larger, more open bodies of water. These fish include freshwater fish like bass, salmon, walleye, perch and ocean fish like shrimp, bluefish and mullet. A wide variety of reptiles, insects, amphibians and crustaceans also breed and live in wetlands. Frogs, toads, turtles, salamanders, dragonflies, water spiders, clams, and crayfish flourish in wetland habitats. Many mammals depend on wetland areas.

The importance of vegetation associated with wetlands cannot be overlooked. Plants absorb nutrients and help cycle them through food webs. Plants also help keep nutrient concentrations from reaching toxic levels. Plants slow down water flow, causing silt to settle out. The dense "jungle" underwater provides a refuge for young and small fish hiding from predators. Through photosynthesis, it converts solar energy into an energy source available to other life forms as food. Plants remove carbon dioxide and add oxygen into the system. They control flooding by dampening flood surges in the watershed, a characteristic especially important to towns and cities near rivers. When runoff from rains are high, wetland areas slow down the water and absorb excess flows until it gradually drains. In drier periods, wetlands can hold precious moisture long after open bodies of water have disappeared.

Wetland ecosystems contain an intricate community of organisms. Bacteria are at the base of the food web, promoting decay of the deceased plant and animal material, in a process that creates detritus. Snails and small fishes also feed on this partially decomposed detritus, and in turn these detritus feeders become food for larger organisms. At the top of the food web are the migratory birds that move through the area seasonally, feeding on fish that live in the waters of the wetlands.

IV. Student Learning Objectives: (Objectives start with verbs giving student outcomes that are observable and/or measurable. Include objectives that address changes in cognitive (content knowledge), affective (values, attitudes) and psychomotor (hands-on) domains.)

The student will be able to demonstrate and understanding of the concept of interconnectedness of the organisms in a wetland ecosystem and the heirarchy of the food chain.

V. Resources and Materials:

1. A classroom ecology
2. Large illustration of the food web in a wetland setting.

VI. Instructional Procedures: (Focus on what teacher does.)

Present a short lecture on the wetland ecosystems : with cultural perceptions; as regulators of hydrologic flows; with a rich diverse wildlife; with the importance of vegetation; and as a community of organisms.

Conduct the Observation lessons, identifying the components; then role play of the system.

• Have the students gather around the Living Machine so that all can see the animals and plants in the water.
• Have the students name all the animals and plants they can see. Create a list of these organisms on a large poster next to the ecosystem.
• After all plants and animals have been named, remind them that two of the most important members of the food web that is missing in the model are the migratory birds and the sun.
• When the list is complete, divide the students into groups of predators (1/5 of the class), detritus eaters (4/5 of the class)and one sun.
• Have the students arrange themselves into the food chain based on the list of organisms created in step 2. this arrangement may be a simple line, or a more accurate "web".
• Ask each student or group to explain their function in the food chain.
• Explain an environmental situation that would remove one member of the food chain. An example, is the polluted waters that kill the baby mullets. Remove the student representing the mullet.
• Ask the students to explain the implications of removing that organism from the food web. Guide their responses through the ecological effects of altering the feeding dynamics in the system. Discuss population dynamics, such as the effect on population of organisms that feed on the removed species, and the rapid growth in population of those organisms that were once eaten by the removed species. Emphasize the role of the sun as the primary source of energy ( channeled through the plants via photosynthesis) that drives the food web.
• Repeat the exercise a few times, varying the disruptions to the food web. Include a scenario in which a new, non-native species in introduced to the web and becomes an invasive element.
• To close the activity, gather around the classroom ecology and identify within the tanks the animal and plant roles each student played in the food web game.

VII. Student Learning Activities: (Focus on what students do. What do you want students to learn?)

Students will be able to observe and identify the key elements of the living Machine by constructing a meaningful food chain.

Students will demonstrate an understanding of the dynamics of the wetland ecosystem as determined by the population dynamics and food chain.

Students will surmize from evidences and the logic of the food chain the effects of removing a resource link in the chain.

Students will participate in active role play of the parts of a wetland ecosystem.

Students will draw one good habitat with the food chain intact: Students will draw the results of a part being removed and its impact on the system.

VIII. Assessment: (How are benchmarks and objectives assessed? Do students help develop rubrics? Do peers assess each other? Is parent assessment included?)

Assessment will be based on:

• student participation in role playing
• student participation in discussions
• student drawings of the food web comparing and contrasting a healthy and unhealthy ecosystem,

• Include a piece of student work or photo if possible.

IX. Teacher and/or Student Evaluatiohn of Lesson: (Your reflections/comments/cautions/encouragement.)

This activity should take place in one period.