Food Chains, Food Webs, Energy Pyramids

 A visual representation of how energy is transferred in a system GrassGrasshopperSnakeHawk Producer Consumers Produce their own energy (autotrophs) Depend on other organisms for their energy (heterotrophs)

We call each level of the food chain a “trophic” level – meaning energy level. Each trophic level shows how energy is being transferred from one animal to another. Each level is designated with specific terminology.

Primary producer Make their own food from the energy they gain from the sun.

Primary Consumer Get their energy directly from producers. This level of the food chain is occupied by either herbivores or omnivores – those organisms that eat plant tissue as part or all of their diet.

Secondary Consumer Get their energy directly from other organisms. This level of the food chain is occupied by either carnivores or omnivores – those organisms that eat animal tissue as part or all of their diet.

Tertiary Consumer Get their energy directly from other organisms. This level of the food chain is occupied by either carnivores or omnivores – those organisms that eat animal tissue as part or all of their diet.

Beyond tertiary consumers There is a possibility of another level (quaternary consumers). This is a very rare occurrence. The last trophic level is often referred to as the top-level consumer – this is the consumer that doesn’t have many organisms that want to eat it (like humans).

Is the top-level consumer safe? Just because there isn’t an organism that eats them, there is an aspect of a food chain that takes the energy of the top level consumer and places it back into the food chain system.

Fungi Decomposer These organisms feed from the dead tissue. They break it down into simple nutrients that are returned to the soil that is used by the plants.

A. B. C. D. ABCD

A. Primary Producer B. Secondary Consumer C. Tertiary Consumer D. Quaternary Consumer ABCD

 The food chain implies that our consumers only eat ONE thing, but that is not the case  Just like you, animals of all types like a variety of food…  Therefore we rely on a food web to show us the entire energy transfer that is happening within an ecosystem.

A. Yes B. No

 In truth, only 10% of the overall energy is transferred from one trophic level to another.  How does this affect the number of trophic levels an ecosystem can support?  When you start with a limited supply, each level only gets 10% of that previous level  100%  10%  1%  0.1%

0.1% 1% 10% 100% Primary Producer Primary Consumer Secondary Consumer Tertiary Consumer

0.1% 1% 10% 100% The pyramid shows a picture of less energy at each level The pyramid also represents the amount of organisms that can be present at each level More Energy, large population Less Energy, small population

 Only 10% of the previous level’s energy passes on, so where does the rest go?  Law of Conservation of Energy states: Matter (Energy) is neither created nor destroyed.  Therefore, what is not passed on must be used by the organism  The energy is used for basic function  Breathing  Running  Reproduction  Digesting  Released as heat

A. A food web B. A food chain

A. Being made up of many overlapping food chains B. An organism that converts heat or light energy from the sun into other energy C. A model that shows how energy is lost as it is transferred up the food chain D. An organism that gets its energy by eating plants or animals E. A model that shows one set of feeding relationships between a producer and several consumers F. An organism that breaks down dead plants and animals into simpler compounds

A. Being made up of many overlapping food chains B. An organism that converts heat or light energy from the sun into other energy C. A model that shows how energy is lost as it is transferred up the food chain D. An organism that gets its energy by eating plants or animals E. A model that shows one set of feeding relationships between a producer and several consumers F. An organism that breaks down dead plants and animals into simpler compounds

A. Being made up of many overlapping food chains B. An organism that converts heat or light energy from the sun into other energy C. A model that shows how energy is lost as it is transferred up the food chain D. An organism that gets its energy by eating plants or animals E. A model that shows one set of feeding relationships between a producer and several consumers F. An organism that breaks down dead plants and animals into simpler compounds

A. Being made up of many overlapping food chains B. An organism that converts heat or light energy from the sun into other energy C. A model that shows how energy is lost as it is transferred up the food chain D. An organism that gets its energy by eating plants or animals E. A model that shows one set of feeding relationships between a producer and several consumers F. An organism that breaks down dead plants and animals into simpler compounds

A. Being made up of many overlapping food chains B. An organism that converts heat or light energy from the sun into other energy C. A model that shows how energy is lost as it is transferred up the food chain D. An organism that gets its energy by eating plants or animals E. A model that shows one set of feeding relationships between a producer and several consumers F. An organism that breaks down dead plants and animals into simpler compounds

A. Being made up of many overlapping food chains B. An organism that converts heat or light energy from the sun into other energy C. A model that shows how energy is lost as it is transferred up the food chain D. An organism that gets its energy by eating plants or animals E. A model that shows one set of feeding relationships between a producer and several consumers F. An organism that breaks down dead plants and animals into simpler compounds

A. fungi B. animals C. water D. sunlight