*Energy* in Ecosystems

Producers- an organism that uses energy from the sun to produce their own food. Producers are the source of all food in an ecosystem.

Consumers- organisms that must consume other organisms because they cannot make their own food

Primary Consumers- Organism that gets its energy from producers (plants)

Secondary Consumer- a consumer that gets its energy from other consumers. Example: Mouse (consumer of grass) gets eaten by a cat

Tertiary Consumer- a high level consumer (usually a top predator in an ecosystem). Example: Insects (primary consumers) are eaten by frogs (secondary consumers) frogs are eaten by jaguars

Quick Review- Types of Consumers  Herbivore- eat only plants  Carnivore- eat only meat  Omnivore- eat meat and plants  Scavenger- eat dead organisms

Decomposers- breakdown waste and other dead organisms and return raw materials (carbon, nitrogen, oxygen) to the ecosystem.

Decomposers Decomposers act as nature’s recyclers. If an ecosystem did not have decomposers, the raw materials of life would be wasted rotting in the bodies of dead organisms. Luckily decomposers, such as bacteria and mushrooms fulfill their need for energy by decomposing the bodies, and at the same time return simple molecules of oxygen, carbon, and nitrogen to the environment. Since all organisms have a limited lifespan, all food chains and webs end with decomposers.

Food and Food

What is a chain? Food chain- a series of events where one organism eats another to obtain energy. There are normally three to five links in the chain.

Food Chains The first organism in a food chain is always a producer (grass). The second organism feeds on the producer and is called a first-level consumer or primary consumer (mouse). The secondary consumer (snake) feeds on the primary consumer. The tertiary consumer feeds on secondary consumer. The arrows always point in the direction that the energy is flowing, or to the organism that is consuming the energy.

What is a web? Food web- many overlapping food chains in an ecosystem. In a food web you can see how everything is connected to each other.

Food Web A food chain only shows one possible path energy can travel. Just as you do not eat the same thing every day, neither do many organisms. Most producers and consumers are a part of multiple food chains. Organisms can play different roles in different food chains. For instance, an omnivore such as the grouse is a primary consumer when it eats berries and a secondary consumer when it eats butterflies.

Energy Pyramid Energy Pyramid- a diagram that shows the amount of energy that moves from one feeding level to another in a food web. The further along the food chain you go, the less food (and hence energy) remains available. This is why it appears like a “pyramid”

Energy Pyramid