3-2 Energy flow

Producers

The sun is the main energy source of life on earth. Some types of organisms rely on the energy stored

in inorganic chemical compounds. Autotrophs can make their own food

Photosynthesis

Light energy powers reactions that convert CO2 and H2O into sugars + O2

On land: plants Oceans: algae,

cyanobacteria

CO2 + H2O + sunlight C6H12O6 + O2

Chemosynthesis

Some bacteria can use the energy in H2S to make food

Found in sulfur vents, hot springs

Tube worms in an underwater thermal vent

Consumers/ heterotrophs

Must eat to survive. Omnivores: eat

plants and animals Detritivores: feed

on dead matter Decomposers:

break down organic matter

Food chain

Energy flows in only one direction- from the sun to producers, to consumers, etc.

Terrestrial andmarine food chains

Food webs Several food chains

linked together Shows how energy

moves through a community

A change to one part of the web affects all the others

Salt marsh food web

Energy pyramids

Energy is lost as heat or used for growth.

Only 1/10th of the energy is available for the next trophic level

Biomass pyramid

Some questions

What happens to a community if the number or output of the producers is lowered, say in a drought?

What would happen if the decomposers died?

What happens if the top predators are killed by man?