1. Energy Flow Pyramids and Trophic Levels

2. Plant material eaten by caterpillar
Does all the energy this caterpillar eats get
passed to the bird who eats him?
Plant material eaten by caterpillar
100 kilocalories (kcal)
35 kcal
Cellular respiration
50 kcal
Feces
15 kcal
Growth

3. TROPHIC LEVELS Determined by the organism’s source of energy
Organisms are identified by their trophic level according to their name.
Autotrophs
Heterotrophs
Decomposers
Decomposers are a specific type of heterotroph.

4. 1. AUTOTROPHS:
Capture energy from the sun (photosynthetic) or inorganic molecules = chemicals (chemosynthetic) and converts it into usable energy.
Also known as PRODUCERS
produces food (make energy storing molecules),
Eg. Plants, algae and some kinds of bacteria

5. 2. HETEROTROPHS-
Obtains the energy to build their molecules by consuming plants or other organisms
Also known as CONSUMERS
Includes not only primary, secondary, tertiary (etc.) consumers, but also include:
decomposers and detritivores

6. 3. DECOMPOSERS A specific type of heterotroph Can be one of two types:
-Scavenger/Detritivore: Eats dead organisms (carcasses) or detritus (dead organic matter)
Eg. Bear, Dog, Vulture, Crab, Worm, Bacteria
-Saprotroph: Digests matter, extracellularly (outside the cell) by spitting enzymes out and then absorbing the digested material.
Eg. Fungi such as mushrooms

7. Pyramid Models:
graphs which illustrate the trophic levels in a community.

8. Energy Pyramid Model Organisms convert food (glucose) into energy.
This energy is given off as heat which is lost to space.
Energy is a one way path. It is not a cycle.

9. Energy Pyramid Model
An energy pyramid is a diagram that compares energy used by producers, primary consumers, and other trophic levels.
As a rule each trophic level receives only 10% from the trophic level below.
In other words each trophic level loses 90% heat to the atmosphere.

10. Energy Pyramid Model Producers: 123,000 KJ Primary Consumers:
Tertiary Consumers:
123 KJ
Secondary Consumers:
1,230 KJ
Primary Consumers:
12,300 KJ
Producers: 123,000 KJ

11. Biomass Pyramid Biomass is the mass of organisms minus water.
Biomass refers to the amount of carbon and other trace elements in an organism’s body contains.

12. Numbers Pyramid
Illustration of the number of organisms at each level

13. It depends on what they are eating.
How can more people be supported on Earth when there is a limited supply of resources?
It depends on what they are eating.