Energy FlowPyramid of EnergyPyramid of Biomass

Definition of terms

Trophic Level- includes a group of organisms that obtain food in a similar manner

Producers

primary consumers

secondary consumers

Tertiary consumers

Quaternary consumers

Decomposers

Laws of Thermodynamics

Energy can neither be created nor destroyed but can be transformed into different forms.

When energy is transformed from one form to another, there is always some loss of energy from the system usually as low grade heat.

10% Law of Energy Transfer(Lindemann 1942)

during the transfer of energy from organic food from one trophic level to the next, only about ten percent of the of energy from organic matter is stored as flesh. The remaining is lost during transfer, broken down in respiration, or lost to incomplete digestion by higher trophic levels.

Only 10% of energy at a particular trophic level is incorporated to the next trophic level.

Rapid loss of energy explains why food chain rarely has 5 links.

Principles of Energy flow

1. Ecosystems are dependent upon the solar energy flow and finite pool of nutrients

2. The primary source of energy for the ecosystem is the sunlight.

3. All Energy content of organic matter is eventually lost to the environment as heat.

Producer

Primary consumer

Secondary consumer

Tertiary consumer

Quaternary consumer

Decomposer

heat

heat

heat

heat

heat

heat

Ecological Pyramids

Pyramid of Energy

Pyramid of Biomass

Pyramid of Energy- shows that as you go higher the trophic levels, the amount of energy decreases

Pyramid of Energy

Tertiary Consumer

Secondary

consumer

Primary consumer

Producer

Energy of a trophic level

utilized

Producing food

Growth and development

including regeneration

Not utilized about 10% for animals

and 20% for plants

Stored as flesh (becomes part of

the biomass)

Available for the next trophic level

Pyramid of Biomass

Biomass- quantitative estimate to the total mass of living material

- amount of given energy at a given time

-standing crop

Measuring biomass: total volume, dry weight or live weight

Pyramid of Biomass- also shows that the biomass decreases with each level of food chain

Secondary Consumer- 2

snakes (40 grams

Primary Consumer- 30 mice (500 grams)

Producer- 100 m² of grasses (10,000 grams)

Biomass of a trophic level

Not consumed consumed

Digested

Body building growth

Gained by the next

trophic level

Released as:

Heat Inorganic nutrients

Undigested

Undigested fecal waste

Trophic detritus

• Only uses samples from populations, so difficult to measure biomass exactly.

• Time of year that biomass is measured affects the result.

• Organisms of the same size do not necessarily have the same energy content.

• Inverted pyramids may result from producers with high turnover rate.