1. ENERGY and ECOLOGY:
Ecological Pyramids

2. Productivity of Ecosystems
Energy is the currency of ecosystem
Most energy is reflected back into space or is absorbed by atmosphere
Only about 1% of sun light that reaches producers is captured by photosynthesis
Producers convert sun (radiant) E into chemical E that is stored in organic compounds (glucose)
This energy captured by producers enables producers to make billions of kg of organic matter (BIOMASS) each year

3. Primary Productivity
Rate at which producers in an ecosystem build biomass
Set the energy budget for ecosystem
Determines maximum amt of E available to all higher trophic levels in ecosystem
We look at “net productivity”
Total amt of organic material produced minus the amount used by the producers themselves

5. Three Types of Pyramids Represent Trophic Levels in Ecology
Pyramids of Energy
Pyramids of Biomass
Pyramids of Numbers

6. Pyramid of Energy Aka food pyramid Energy flow thru trophic levels
Primary producers covert 1% of energy from sun
Only 10% of energy from one trophic level is passes onto the next
The other 90% is used by the organism to carry out its life processes or it is lost to the environment
So much energy required to maintain an organism
Limited to 3 or 4 steps
Cannot be inverted
Emphasizes E LOSS b/t trophic levels

7. Energy Pyramid

10. Pyramid of Biomass
Total dry weight of living tissue at each trophic level
kg of living tissue/ area
Usually follows traditional narrowing form of pyramid
May be inverted
Ex. Aquatic ecosystems
Zooplankton consume phytoplankton very fast that their biomass actually ends up being larger

11. Biomass Pyramid

12. Ecological Pyramids of Biomass
The total dry weight of organisms (standing crop) in a particular trophic level is referenced as biomass. Most pyramids follow the typical pattern of narrowing at each level, however in some aquatic ecosystems, the pyramid may be inverted. In the example, phytoplankton grow and reproduce so rapidly that they can support a large population of zooplankton even though at any one time, the biomass of phytoplankton is smaller than that of the zooplankton.
References
Campbell, N. E., & Reece, J. B. (2002). Biology (6th ed.). San Francisco: Benjamin Cummings.
Holligan, P. M., Harris,R. P., Newell, R. C., Harbour, D. C., Head, R.N., Linley, E. A. S., Lucas, M. I., Tranter, P. R. G., & Weekly, C. M. (1984). Vertical distribution and partitioning of organic carbon in mixed, frontal, and stratified waters of the English Channel. Marine Ecology Progress Series, 14,
Raven, P. H., & Johnson, G. B. (2002). Biology (6th ed.). McGraw-Hill.
Image Reference
Young, M. (2004). Ecology Biomass Pyramid. Baylor College of Medicine, Center For Educational Outreach.

13. Inverted Biomass Pyramid

16. Pyramid of Numbers
Show the number of organisms at each trophic level in ecosystem
Producers at the bottom, higher trophic levels above
Not always a perfect pyramid
Exception is when small organisms eat larger one (insects eating a tree)

20. Pyramid of Numbers vs. Biomass
Bluebird
Bluebird

21. Ladybirds
Arthropods

22. Arthropods feed on tiny algae. Sardines feed on tiny arthropods
Arthropods feed on tiny algae. Sardines feed on tiny arthropods. Dolphins feed on sardines.
Antelope feed on grass. Lions feed on antelope. Fleas live on lions and suck their blood.
Greenflies feed on rose bush. Ladybirds feed on greenflies. Swallows feed on ladybirds.
Zebras feed on long grass. Ticks suck the blood of zebras. Birds sit on the zebras’ backs and eat the ticks.