Ecosystem Roles: Producers, Consumers, Decomposers

Types of Heterotrophs

• Heterotrophs are consumers that obtain energy by consuming other organisms
• Scavengers/Detritivores feed on the tissue of dead organisms (both plants and animals)
• Examples of Scavengers/Detritivores: Vultures, Crows, and Shrimp
• Decomposers absorb any dead material and break it down into simple nutrients or fertilizers
• Examples of Decomposers: Bacteria and Fungi

Decomposers

• Decomposers break down nutrients in the dead material and return it to the soil
• Producers can then use the nutrients and elements once it's in the soil
• Decomposers complete the ecosystem, returning essential molecules to the producers

Ecological Classification

• Ecologically speaking, grasses are classified as producers
• Deer are classified as consumers

Essential Components of an Ecosystem

• Two groups that are absolutely essential to the functioning of an ecosystem: Producers and Decomposers

Energy Source for Producers

• Producers obtain energy from the sun

Requirements for Autotrophs

• Autotrophs require energy, water, carbon dioxide, and nutrients from the environment to make their own food

Food Webs

• Energy flows from one organism to another when it is eaten
• Each step in this transfer of energy is known as a trophic level
• The main trophic levels are producers, consumers, and decomposers
• The flow of energy through ecosystems is linear
• Energy flow occurs in food chains

Food Chains

• A food chain is a simple and direct energy flow from one trophic level to the other
• Food chains always start with a plant
• Example of a food chain: Lettuce is eaten by the slug, the slug is eaten by the bird

Food Webs

• A food web is a more complex and interconnected network of food chains in an ecosystem
• Most organisms eat more than just one organism
• Food webs are more complex and involve lots of organisms

Trophic Level

• Energy flow is linear, or one-way, in ecosystems
• Energy can move along a food web from one trophic level to the next trophic level as long as it is not used to do biological work
• Once energy has been used by an organism, it is lost as heat and is unavailable to any other organism in the ecosystem

Transfer of Energy

• When a zebra eats the grass, it does not obtain all of the energy the grass has
• When a lion eats a zebra, it does not get all of the energy from the zebra
• Only 10% of the energy from one trophic level is transferred to the next
• This is called the 10% law

Energy Loss in a Food Chain

• Only 10% of energy is passed along to the next level in a food chain
• The rest of the energy is lost through waste, heat, movement, and respiration

Identify the different roles in an ecosystem, including producers, consumers, scavengers, decomposers and their functions in the nutrient cycle.