Energy Flow Chapter 16 Food Chains, Food Webs, Energy Pyramids

Begins with the SUN Photosynthesis 6CO 2 + 6H 2 O + sunlight & chlorophyll  C6H 12 O 6 + 6O 2

Organisms that use photosynthesis are called PRODUCERS.

Producers use 90% of the energy they make for their metabolic funtion.

The energy not used by producers is passed on to organisms that cannot make their own energy. – 10%

Organisms that cannot make their own energy are called CONSUMERS.

Primary consumers: eat producers eat producers AKA herbivores (plant-eaters)

90% of the energy the primary consumer gets from the producer is used by the consumer. This energy is available for another consumer. – 10%

Some of the energy moves into the atmosphere as heat.

A consumer that eats another consumer for energy: secondary consumer (2 nd eater) May be a predator scavenger

A consumer that eats a consumer that already ate a consumer: Tertiary consumer Tertiary consumer (3 rd Eater) (3 rd Eater) May be a May be a predator predator scavenger scavenger

Consumers that hunt & kill other consumers are called predators. The animals that are hunted are called prey.

Consumers that eat already dead things are called scavengers.

Another way of showing the transfer of energy in an ecosystem is the ENERGY PYRAMID.

Ecological Pyramid Trophic level: energy level Trophic level: energy level ( a step in a food chain or food pyramid) ( a step in a food chain or food pyramid) shows which level has the most energy and the highest number of organisms shows which level has the most energy and the highest number of organisms

Ecological Pyramid

Energy pyramids show the amount of available energy decreases down the food chain

Ecological Pyramid

Vocabulary Parasitism: Parasitism: One organism feeds on another living organism. Require a “host” in order to survive. One organism feeds on another living organism. Require a “host” in order to survive. Mutualism: Mutualism: Both species have a symbiotic or beneficial-to-both relationship. Both species have a symbiotic or beneficial-to-both relationship. Commensalism: Commensalism: One species benefits; the other is not harmed or helped. One species benefits; the other is not harmed or helped.

The transfer of energy from sun to producer to primary consumer to secondary consumer to tertiary consumer can be shown in a FOOD CHAIN.

Food Chain

Food Web Most organisms eat more than JUST one organism Most organisms eat more than JUST one organism When more organisms are involved it is known as a FOOD WEB When more organisms are involved it is known as a FOOD WEB Food webs are more complex and involve lots of organisms Food webs are more complex and involve lots of organisms

Food Webs: Are interconnected food chains They show the feeding relationships in an ecosystem

Food Web

Notice that the direction the arrow points  the arrow points in the direction of the energy transfer, Notice that the direction the arrow points  the arrow points in the direction of the energy transfer, NOT “what ate what” NOT “what ate what”

Food Web

Biomass The total mass of the organic matter at each trophic level is called biomass The total mass of the organic matter at each trophic level is called biomass Biomass is just another term for potential energy – energy that is to be eaten and used. Biomass is just another term for potential energy – energy that is to be eaten and used. The transfer of energy from one level to another is very inefficient (10% Law) The transfer of energy from one level to another is very inefficient (10% Law)

Biomass