Energy Flows and Ecosystems The sun provides the energy for all life on earth.

Photosynthesis Green plants trap the suns energy through the process of photosynthesis. Without photosynthesis there would be no life on earth

Productivity Gross primary productivity (GPP) – the total amount of energy absorbed and fixed by green plants through photosynthesis Net Primary Productivity (NPP) – the amount of useful energy fixed by plants after respiration (measured in kg/m2/yr) Plant productivity varies depending on the environmental conditions (light, warmth, water, nutrients)

Gross primary productivity (GPP) – the total amount of energy absorbed and fixed by green plants through photosynthesis

Net Primary Productivity (NPP) – the amount of useful energy fixed by plants after respiration (measured in kg/m2/yr)

Plant productivity varies depending on the environmental conditions (light, warmth, water, nutrients)

Food Chains and Webs

Trophic Levels, Energy Flows and Losses

The Trophic Pyramid

So, which is a more efficient way to feed a population? To grow crops or graze cattle?

Key Terms Summary Photosynthesis Productivity (GPP and NPP) Food chains and webs Producers (autotrophs) Consumers (herbivores, carnivores, omnivores) Decomposers Trophic levels and pyramid

Photosynthesis

Productivity (GPP and NPP)

Food chains and webs

Producers (autotrophs)

Consumers (herbivores, carnivores, omnivores)

Decomposers

Trophic levels and pyramid