Transcript Energy flow in a community - Sonoma Valley High School

3-2 Energy flow
Producers
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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
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CO2 + H2O + sunlight
Light energy
powers reactions
that convert CO2
and H2O into
sugars + O2
On land: plants
Oceans: algae,
cyanobacteria
C6H12O6 + O2
Chemosynthesis
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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
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Must eat to survive.
Omnivores: eat
plants and animals
Detritivores: feed
on dead matter
Decomposers:
break down organic
matter
Food chain
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Energy flows in only one direction- from the sun to
producers, to consumers, etc.
Terrestrial and
marine food
chains
Food webs
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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
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Energy is lost as
heat or used for
growth.
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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?
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