Ecosystems and Conservation Biology

Chapter 36

Part 2

36.2

• Energy flows through ecosystems

Productivity of Ecosystems

• Only about 1% of the sun’s energy is harnessed by photosynthesis

• Still enough to produce Earth’s biomass– Organic material

Productivity of Ecosystems

• Primary productivity– Rate at which producers in an ecosystem

build biomass

Ecological Pyramids

• Follows transfer of energy through ecosystem

Energy Pyramids

• Emphasizes energy loss from one trophic level to the next

• In general, only 10% transferred each time

Biomass Pyramid

• Represents actual biomass (dry mass of all organisms) in each trophic level

Pyramid of Numbers

• Number of individual organisms in each trophic levels