ENERG Y and ECOLOGY: Ecological Pyramids
May 16, 2015
ENERGY and ECOLOGY:
Ecological Pyramids
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
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
Three Types of Pyramids Represent Trophic Levels in Ecology
Pyramids of Energy Pyramids of Biomass Pyramids of Numbers
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
Energy Pyramid
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
Biomass Pyramid
Ecological Pyramids of Biomass
Inverted Biomass Pyramid
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)
Pyramid of Numbers vs. Biomass
Bluebird
Bluebird
ArthropodsLadybirds
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.