I. Energy Flow

A. Producers Make their own food through

photosynthesis using sun, water, and carbon dioxide

Plants, algae

B. Consumers Feed on other organisms, cannot

make their own food Example: humans, bear, fox, cow,

insects

C. Decomposers Break down dead organisms, recycling

chemicals to soil, water, & air Example: fungi, bacteria, certain

insects like earthworms, centipedes, sow bugs

D. Energy enters ecosystems as LIGHT is converted to CHEMICAL ENERGY by producers and exits the ecosystem as HEAT.

II. Food Chain

A. Trophic levels

Feeding level, represents

position in food chain/food web

B. Food Chain pathway of food transfer from one trophic level to another

You always start with PRODUCERS on the left/bottom of a food chain.

C. Producer --> Primary Consumer--> Secondary Consumer--> Tertiary

Consumer

D. Decomposers are found at EACH trophic level.

III. Food Web

A. Definition: pattern of feeding represented by

interconnected branching food chains- more realistic representation of feeding relationships.

B. Draw a simple food web

IV. Three Kinds of Ecological Pyramids

A. Energy pyramid Description: diagram representing energy

loss from one trophic level to the next

10% Rule- an average of 10% of the available energy at a trophic level is converted to biomass in the next higher trophic level.

B. Biomass Pyramid Description: represents the actual

dry mass of organisms at each trophic level

C. Pyramid of Numbers Description: the number of

individual organisms in each trophic level of an ecosystem

V. Chemical Cycles

A. Basic plan Producers Consumers Decomposers

B. Carbon-Oxygen Cycle

CO2 Used for photosynthesis

Product of photosynthesis is sugar and oxygen

During cellular respiration, sugar is broken down in presence of oxygen, and CO2 is release into air

The Carbon Cycle

The Carbon Cycle

C. NITROGEN CYCLE

Nitrogen found in amino acids, make

proteins

80% of it is in atmosphere

Nitrogen Fixation- certain bacteria “fix” nitrogen gas into ammonium

Found near peas, beans, alfalfa

Nitrification- other bacteria convert ammonium into nitrate

Plants can USE nitrate

Eutrophication!

The Nitrogen

Cycle

The Nitrogen

Cycle