The Eco Pyramid
by Michael Stahl
An ecosystem is a community of living organisms interacting with one another as well as with
nonliving things. One very important aspect of an ecosystem is the energy that flows through it.
Energy is exchanged between members of an ecosystem, creating an energy flow and assisting in
the continuation of life. However, not all of the organisms living in an ecosystem absorb equal
amounts of energy. An eco pyramid effectively illustrates the amounts of energy that are absorbed
by the different types of organisms in an ecosystem.
The power of the earth's sun gets the energy flow of most ecosystems going. Solar rays enter the
earth's atmosphere and reach the surface where plants utilize the energy from them. Through a
process called photosynthesis, plants like trees, grass, and bushes, create food for themselves.
Plants are able to take in carbon dioxide from the atmosphere, and their roots absorb water from
the surrounding soil. Plants then use the solar energy and the hydrogen from water to transform
the carbon dioxide into a nourishing carbohydrate. With photosynthesis complete and food and
energy absorbed, the plants release the oxygen part of the water that they had taken from the soil
back out into the atmosphere. Other living things, like human beings, take in oxygen in the
breathing process. The plants of an ecosystem are called "autotrophs," which means "selffeeders." They are also called "producers" in an ecosystem.
The carbohydrates that were produced by the photosynthesis process give the plant energy to
continue on living. Herbivores are animals that eat mostly, if not strictly, plant life. Termites, koalas,
field mice, and deer are a few examples of herbivores. Deer feed on leaves and grass, consuming
the green plant life's energy. To consume means to eat something and absorb its nutrients for
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The Eco Pyramid
survival. After eating the plants of their choice, deer will then digest the plants and use whatever
nutrients the plant had stored inside to create energy so that they can continue to live. The
herbivores of an ecosystem are called "primary consumers." Some of the energy that the
herbivores use is lost in the ecosystem when they create body heat. For example, when deer run
and their bodies warm up, the excess heat within their bodies escapes into the atmosphere. If that
did not happen, the deer's bodies would get too hot and their organs would fail to work any longer.
Energy is transferred again in an ecosystem's energy flow from primary consumers to "secondary
consumers." Carnivores, or meat eaters, act as secondary consumers. Lions, tigers, and polar
bears are carnivorous. They eat the meat of the herbivores after a hunt. When tigers eat their
prey's meat, they go on to digest it and use the energy from it for their own survival. Like the
herbivores in the previous section of the energy flow, carnivores also give off heat energy when
their bodies warm up from exercise. Unfortunately for the carnivorous secondary consumers, they
too will eventually find themselves targeted for their energy by other members of their ecosystem:
the tertiary consumers.
Secondary consumers are carnivorous predators, meaning that they hunt down other animals and
kill them for food. However, these animals are not at the very top of the food chain and they too
can be hunted and utilized as a meal. Tertiary consumers are predators who lie at the top of the
food chain. Human beings are the most obvious example of a tertiary consumer. Unlike the
secondary consumers, tertiary consumers are not normally preyed upon by other members of the
ecosystem.
Like the primary and secondary consumers, the tertiary consumers give off body heat. That
energy is released into the atmosphere. Even if consumers or producers aren't hunted or eaten, all
living things eventually die. When they do, they decompose. Bacteria and fungi attach themselves
to a dead producer or consumer and begin to break down the matter of the body, releasing
nutrients into the soil. These nutrients are then used to give life to new plants so that new energy
from the sun can flow through the eco pyramid.
Which sentence best describes why the image of the eco pyramid is included in this selection?(1 point)
Responses
The image of the eco pyramid clarifies any misunderstandings for the reader.
The image of the eco pyramid clarifies any misunderstandings for the reader.
The image of the eco pyramid introduces the main characters of the passage.
The image of the eco pyramid introduces the main characters of the passage.
The image of the eco pyramid shows the reader a symbolic representation of the information described in the selection.
The image of the eco pyramid shows the reader a symbolic representation of the information described in the selection.
The image of the eco pyramid describes the setting of the passage.