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.