Energy in Ecosystems Food Chains, Food Webs and Energy Pyramids Courtesy:

Producers (Autotrophs) Photosynthetic organisms Photosynthetic organisms – Capture energy from sunlight, CO 2 and H 2 O – Most producers are photosynthetic Chemosynthetic organisms Chemosynthetic organisms – Capture energy from chemical compounds in the surroundings

Consumers (Heterotrophs) Herbivores Herbivores – Eat only plants and fungi Omnivores Omnivores – Eat both plants/fungi and animals Carnivores Carnivores – Eat only animals Detrivores Detrivores – Eat dead organic matter Decomposers Decomposers – Break down organic matter into simpler compounds

Movement of Energy Trophic Structures Trophic Structures – Manner in which energy moves through an ecosystem – Each ecosystem has its own unique trophic structure

Biotic Energy Movement Producers Producers – Autotrophs (Photosynthesizers, Chemosynthetic organisms) Primary consumers Primary consumers – Herbivores and omnivores that eat producers Secondary consumers Secondary consumers – Carnivores and omnivores that eat herbivores Tertiary consumers Tertiary consumers – Carnivore eats another carnivore Decomposers and Detrivores Decomposers and Detrivores – Consume decaying producers and consumers

Think Pair Share  Think of at least two animals that fall into each category that we discussed.  How is the energy transferred? What forms might this energy take? Think back to the reading.  Create a simple food chain that includes one organism from each category.  Look at the organisms from the food chain activity last class. Label each with the correct category (primary consumer, producer etc.)

Do This! Glue the image provided onto the next left hand side page. Glue the text to the adjacent right side page. Under the image write 2 – 5 sentences explaining what you think the image is showing.

Food Chain  Energy is lost in each step up a food chain  Only 10 percent of the energy from one level on the food chain is available to the next level  So…from the leaf to the Eagle, what percent of energy remains in the system?

Food Webs Many consumers and decomposers have more than one food source Movement of energy occurs in complex webs rather than in simple chains

Arctic Marine Food Web

A Simplified Food Web?

Energy Pyramids Energy pyramids show the reduction of available energy at each higher trophic level

Biomass Distribution

Why a Pyramid? most Producers must comprise most of the mass of the biotic part of an ecosystem – This is the ONLY place where energy (solar) enters the ecosystem Energy is always lost in the form of heat, so energy transfers are no more than 10% efficient Each trophic level must be supported by a 10/1 energy ratio below it most Producers must comprise most of the mass of the biotic part of an ecosystem – This is the ONLY place where energy (solar) enters the ecosystem Energy is always lost in the form of heat, so energy transfers are no more than 10% efficient Each trophic level must be supported by a 10/1 energy ratio below it

The 10% Rule