Objectives•Analyze the energy pathways through the different trophic levels of a food web or energy pyramid•Evaluate the impact of changes in energy within different trophic levels EQ: How does a farmer’s choice of pesticides affect the health of humans?

Energy flow

What is a food chain?A food chain is series of step in

which organisms transfer energy by eating and being eaten.

What is a producer--autotrophAn organism that creates it’s own food

through photosynthesis

What can you think of that might be the most common energy source for all producers?

The SUN

Producers aka AUTOTROPHSPrimary producers are

“organisms capable of producing their own food”

We can also say that they are photosynthetic, use light energy.

Examples of primary producers include algae, phytoplankton, and large plants.

http://i.ehow.com/images/GlobalPhoto/Articles/4729527/sun-plant_Full.jpg

CONSUMERS AKA HETEROTROPHSAnimals AND fungi are consumers because they

cannot create their own food, they must eat (consume) plants or other animals to get the energy they need.

Click “Here” to video on Phytoplankton

Classify Consumers1. Primary Consumers: Herbivores eat plants

2. Secondary Consumers: Carnivores that eat herbivores

3. Tertiary Consumers: Carnivores that eat other carnivores

Detritivores: Animals that eat dead materials and organic wastes (aka decomposers)

Detritus: waste and remains of dead organism.

What is a food web?A food web is “an interlocking pattern of food chains2”

•Every ecosystem includes both biotic (living) and abiotic (nonliving) factors.

•The biotic factors are organized into trophic levels.

Trophic level: an organism’s position in the food chain

Each trophic level provides 10% of its total energy to the next level.

SUNLIGHT ENERGY

90% of the energy in each trophic level is lost to the environment as heat.

SUNLIGHT ENERGY

Heat Loss

Heat Loss

A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem.

tertiaryconsumers

secondaryconsumers

primaryconsumers

producers

5

5000

500,000

5,000,0005,000,000producers

• A vast number of producers are required to support even a few top level consumers.

Pyramids of Biomass and Numbers

The total amount of living tissue within a given trophic level is called its Biomass

Biomass is usually measured:

# of organic matter _______________________

area

Food Web ActivityWith your group, create a food web with at least 15

organisms using the Marine Food Web Packet. Draw the food web on your poster. The food chain and food web must include a producer, decomposer, and three levels of consumer (primary, secondary, tertiary). Label them (use color coding).

 On the same side of your poster draw a trophic

pyramid using at least 7 of your organisms. Label the producers with 100% energy and then label each of the other levels with how much energy they receive.