The Web of Life

Objectives

1. Students will be able to identify some animals and plants found at in a coastal habitat community or related wetland areas and to describe how they are interdependent on each other.

2. Students will also be able to describe what happens to the rest of the food web when one or more organisms disappears due to a natural or manmade disturbance to the ecosystem.

Materials

1. food web cards

2. one or more large balls of yarn or string

Background

A food web is a combination of all the food chains found in an ecosystem. It begins with the producers, or plants that use sunlight, carbon dioxide, and water to make the sugar glucose. The animals that eat plants, herbivores, are known as the primary consumers. The animals that eat the herbivores, the carnivores, are known as secondary consumers. This goes on and on to tertiary and quaternary consumers. Other organisms are important as the decomposers, who feed on dead or waste material and recycle nutrients back into the habitat. Removing any one of these organisms can have a disastrous effect on the ecosystem, causing a partial collapse of the food web.

Procedure

1. Read the background material aloud in class. It may be helpful to draw an example of a food chain or food web on the board, and to make a diagram with producers on the bottom, with the primary consumers above them, the secondary consumers above the primary consumers, and so on. Make food web cards (from the list below) on large index cards. Punch 2 holes in each card to put string through and laminate.

2. Either go outside or push desks back to allow a large area for your "web".

3. Have students stand in a circle.

4. Hand out the food web cards with attached string to go around the students' necks. You now have your web components.

5. Starting with the algae and other plants, give these students the end to a ball of string.

6. Ask "Who eats this plant?" When the right animal has been named, unravel the string to reach that student as they stand in the circle. Have them wrap the string around their wrist once.

7. Then ask "Who eats this animal?" Do the same with that student, unraveling the string across the circle to reach that student, who then wraps string once around their wrist. Ideally, many students will end with more than one string wrapped around their wrists, showing they eat more than one thing.

8. Continue until a web is formed. Have the students notice how everything is interconnected.

9. Then explain to the students that there has been an oil spill that contaminated and killed all the birds. The student who represents birds must drop that string and anyone connected to him or her must also drop their string. Have students notice how many of them are affected by this.

10. Have a brown tide kill off the grass and see who is affected. Then have a red tide bloom kill off the fish to show the difference in the effects of two tides

Create Food Web Cards with the following names:


Seagrass


Rattlesnake



Sun


Rain



Oyster


Blue Crab



Peregrine Falcon


Marshhay Cordgrass



American Oyster Catcher


Periwinkle
Snail



Algal Mat


Coyote



Red-tailed Hawk


Pocket Gopher



Turkey Vulture


Grass Shrimp



Red Drum


Great Blue Heron



Speckled
Trout


Roseate Spoonbill



Mourning Dove


Jackrabbit



Swamp Sparrow


Piping
Plover





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