Science Notes
Producers, Consumers
and Decomposers
All energy on earth starts
from the sun.
The Sun
energy from
the sun
 allows plants to make their
own food
plants
(producers)
 use energy from sun,
nutrients from soil, and
carbon dioxide from water
and air to make food
 store energy (in the form
of carbon) in leaves, stems
and roots
 all other living things on
earth get energy from plants.
consumers
any form of life on earth
that must eat other things to
survive

cannot make their own food
 many different kinds of
consumers
 labeled by the number of
steps they are away from
plants, in the food chain
primary consumer  eat plants to survive
 get energy directly
from plants
 one step away from
plants
 Ex: caterpillar eats
a leaf (from plant);
elephant eats bark of a
tree; cow eats grass;
squirrel eats
nuts (from Plant)
secondary consumer  organisms that eat
primary consumers
(plant eaters) to survive
 get their energy from
plants second-hand, by
eating the animal or
insect that ate the plant
 two steps away
from the plant
Ex: owl eats mouse
that eats berry (from
plant); spider eats insect
that eats leaf (from
plant); lion eats deer that
eats leaves (from plant)
tertiary consumer  organisms that eat
secondary consumers to
survive
 get their energy from
plants third-hand, by
eating the animal or
insect, that ate the animal
or insect, that ate the
plant
 three steps away
from the plant
 Ex: owl eats the
snake, that ate the
mouse, that ate the
berry(from plant);
spider eats a
dragonfly, that ate the
insect, that ate the
plant;
hawk eats the fish,
that ate the smaller
fish, that ate the
seaweed (plant)
top consumer
 not eaten by any other
consumer
on top of the food
chain
 can be primary,
secondary or tertiary
consumer
decomposers
 break down remains of
dead organisms
 play very important role
in ecosystem
 help release trapped
energy (in the form of
carbon) in dead organism
back to the earth.
 Ex: tree dies,
energy is trapped in
tree stump from when
tree was alive
 mushrooms grow on
dead stump and help
break down
(disintegrate) what is
left of tree
 as tree stump
‘disintegrates’, trapped
energy is released back
into soil and air.