1. Ecology: Day 3 notes
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2. Ecological Pyramids: Another way of showing relationships in ecosystems, Three Types: 1. Energy Pyramid 2. Biomass Pyramid 3. Pyramid of Numbers

3. Energy Pyramids
Energy pyramid shows how energy is spread out among different trophic levels: They compare energy used by producers and other organisms on different trophic levels

4. Energy Pyramids
Energy used: Between each level of an energy pyramid about 90% of the energy is used up in the organism’s life processes (growing, repairing, moving, getting food, having kids, etc.) All of these use heat, which is then lost to the environment.
90% of the energy of a trophic level is lost as heat to its environment at that level
energy transferred
90% energy
lost
10%

5. Energy Pyramids 10% Energy transferred:
Only 10% of the energy at each level is transferred from one trophic level to the next
energy transferred
10%

6. Energy Pyramids
How much energy do the secondary consumers get? How much energy do the top consumers receive?
0.1% 1%

7. Biomass Pyramids
Biomass is  a measure of the total dry mass (weight) of organisms in an area.
tertiary
consumers
secondary
primary
producers
75 g/m2
150g/m2
675g/m2
2000g/m2

8. Pyramid of Numbers
A pyramid of numbers shows the number of individual organisms at each trophic level in an ecosystem
tertiary
consumers
secondary
primary
producers 5
5000
500,000
5,000,000

9. Pyramid of Numbers- Generally, a large number of producers are required to support even a few top level consumers

10. Pyramid of Numbers
But not always: very large producers, like large trees in forests, can produce a non-“pyramid” shaped pyramid of numbers. One tree can support hundreds of other life forms (insects, birds, squirrels, etc.). This type of pyramid can actually be inverted or diamond shaped.
Many insects
A few very big trees

11. Different shaped Pyramid of Numbers

12. Energy vs. Numbers Pyramid