BACKGROUND:
Biomes have physical, as well as biological, characteristics
that one must consider. The biological part of the system usually consists
of four or five energy levels. These are called trophic levels and
are based on how far the original energy has come through the community.
The first level would be considered the producer level.
This is the part of the community that captures and stores solar energy
in photosynthesis and releases oxygen. The rest of the community
is completely dependent upon this level. The rest of the system are
collectively called consumers, which are defined as "eating" their meals.
The second level would consist of herbivores and can range
in size from a small microorganism to an elephant. Any organism that
eats the producer is considered the second trophic level of the food chain.
Carnivores are the third trophic level of the biological system.
The energy is now one more step removed from its original source.
There can be several trophic levels of carnivores. A tiger can eat
other smaller carnivores. Some organisms, like man, are neither true
carnivores nor herbivores, they care classified as omnivores, sometimes
eating plant material and sometimes eating other animals.
Decomposers break down organic structures and substances, releasing
compounds and elements back into the environments. This group would
constitute another trophic level.
PROCEDURE:
- Trophic levels help develop a flow of energy
through any biological system. Students can use the worksheet to
develop their own levels of producers, decomposers, herbivores, and carnivores.
- Read Working on a Food Chain and go over the
vocabulary words.
- Instruct students to group the different organisms by
cutting them out and sorting them into producers, decomposers, herbivores,
and carnivores.
- ANSWERS: Producers (3,8); Decomposers (1,6); Herbivores
(7,9,10); Carnivores (2,4,5,11).
