BACKGROUND:
An ecosystem occurs when living animals, plants, and
microbes form a community which includes producers and consumers.
Producers are those organisms that make their own food using sunlight,
nutrients, and water. Producers are autotrophs or organisms that
utilize the sunlight and chlorophyll within the plant to produce energy
for the plant to grow. Heterotrophs are those organisms on the food pyramid
that eat producers.
Students have learned about coral and where they live.
Coral are consumers. In some cases they depend on algae that grow
within the coral for food in what is termed symbiotic relationships.
Coral are also debris feeders and rely upon whatever "falls" into their
tentacles to be put in their stomachs. The eating habits of coral
are complicated.
The food web concept is an extension of the food chain.
The food chain simply traces who eats whom within an ecosystem (a community
of organisms interacting with one another and with their environment.
By itself, it doesn't give the whole picture of what is really going on
in an ecosystem. Many animals feed on several different types of
food, humans eat several different kinds of plants and animals. Because
of these more complex eating patterns, different food chains intermix and
form a "web-like" pattern called the food web.
PROCEDURE:
- Within the food web there are different tropic levels.
Students should cut out the pictures and glue a piece of paper into Producers,
Primary Consumers, Secondary and Tertiary Consumer as in the diagram below.
- Tell the students that energy loss becomes greater as you go
up the pyramid and the number of organisms becoming less in number as you
go up.
- Ask students what the difference between a carnivore
and a top carnivore means. A top carnivore could eat another organism
that is also a carnivore. A herbivore would be the producer.
- The answers are as follows: Producers: 2,3,8; Primary
consumers:5,6,10,11; Secondary Consumers: 1,4,9; Tertiary consumer: 7.
