Ecosystem Notes

Primary Learning Objectives To be able to explain what an energy pyramid is and what it represents.

Ecosystems

Ecosystem: The community of organisms living in an area, along with their nonliving surroundings.

What do the arrows in a food web represent?

Arrows represent the direction of energy flowing through the ecosystem.

Energy When an organism in an ecosystem eats, it obtains energy. The organism uses some of this energy to move, grow, reproduce, and carry out other life activities.

Energy This means that only some of the energy it obtains will be available to the next organism in the food web.

Energy Pyramid A diagram called an energy pyramid shows the amount of energy that moves from one feeding level to the next in a food web. Each level is called a trophic level.

Energy Pyramid The most energy is available at the producer level of the pyramid. As you move up the pyramid, each level has less energy available than the level below.

Energy Pyramid In general, only about 10% of the energy at one level of the energy pyramid is transferred to the next higher trophic level.

Energy Pyramid The other 90% of the energy is used for the organism’s life processes and is eventually released as heat into the environment.

Energy Pyramid

Energy Pyramid Since there is less energy available to the higher levels in the energy pyramid, this means that there are fewer organisms as you go move up the pyramid.

Note that as we go up, there are fewer giraffes than trees & shrubs and even fewer lions than giraffes.

Where do the Producers get their energy from?

Producers get their energy from the Sun.

Energy Energy is unique compared to many other abiotic factors in the environment because it comes to earth in the form of light and heat from the sun and the earth loses energy as it radiates light and heat back out into space.

Energy In Energy Out

All other abiotic factors that essential for life, such as water, must be recycled.