BACKGROUND:
An ecosystem illustrates the relationship of plants and
animals with each other and with the environment. Ecosystems can
be as large as the ocean or as small as an aquarium. The only factor
in determining an ecosystem is the exchange of nutrients, gases, or processes
that aid or overcome another organism. Simply, an organism will help
another one to survive by doing something essential to the other's survival
or to survival of the environment, or will simply kill or eat the other.
Irrespective of the size of the ecosystem, plants and animals will continuously
live in a never-ending cycle of life.
The first step in the ecosystem begins with the Sun. The
majority of primary producers are plants whether they are in, the water
or on land. Plants use the energy from the sun to produce food
in the form of simple sugars. Photosynthesis, is very vital to the
survival of animal life. Animals depend just as much on photosynthesis
as plants do. The plants that produce sugars by photosynthesis are
called producers. The producers are then eaten by several different
kinds of organisms. The animals that eat primary producers are called
primary consumers. In the water, fish and other animals eat tiny
green plants called algae. The algae are primary producers and the
animal and fish are consumers.
As the cycle continues, the small fish that eat the algae will
be eaten by larger fish. This cycle that exists from producer to
different consumers is called the food chain.
PROCEDURE:
- Discuss with students the food
chain and food web.
- If you have an aquarium in your classroom, you
may want your students to use that instead of the worksheet. The
purpose of this worksheet is to determine the food chains that might be
in an aquarium. For instance, in the worksheet one food chain is:
Sun - algae - protozoa - insect - fish. Ask the students if there
are more than one food chain in the aquarium? Yes, another food chain
would be Sun - algae - newt. Sun-algae -snail - fish, may be another
food chain. Together they create a food web, which also takes into
account that the fish might actually eat the poop of the snail. Food
webs can be intriciate.
- If you discuss a real aquarium, you would have to discuss
the different types of fishes because some fish eat other fish. Also,
when fish have babies, they are usually eaten by bigger fish.
