Science NotesProducers,

Consumers and Decomposers

All energy on earth starts from the sun.

The Sun

energy from the sun

plants (producers)

allows plants to make their own food

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.