2.
5 Decomposers
The food chains and food webs are made up of living organisms.
But what happens to dead organisms, and the waste material
that they produce?
All of these substances contain organic matter.
Many micro-organisms can break down (decompose) organic
matter.
This is where they get their energy.
Organisms that get their energy by breaking down dead bodies
and waste from animals and plants are called decomposers.
Earthworms, fungi, some insect larvae and bacteria are
decomposers.
Organic matter consists
mainly of the living organisms
in the soil (“the living”), the
fresh residue (“the dead”), and
the well-decomposed (or
burned) material physically or
chemically protected from
decomposition (“the very
dead”).
How do decomposers feed?
Inside your digestive system, you produce enzymes that
break down large molecules - such as starch and protein -
into small ones.
The small molecules can then be absorbed through the
walls of your digestive system, and get into your blood.
Decomposers also produce enzymes.
But many decomposers do not have digestive systems.
The diagram shows how a fungus breaks down bread.
The fungus is made of many tiny thread-like structures, called
hyphae.
The hyphae produce enzymes that digest the starch and
protein in the bread around them.
The small molecules that are produced can then diffuse into
the hyphae.
The fungus can use them for energy, or for making new cells
for growth.
.
Mouldy bread seen through a microscope
The importance of decomposers
• Many people feel a little bit sick when they see decomposers
feeding.
• But decomposers are really important.
• All the dead bodies and waste material - including animal faeces -
would just pile up on the Earth.
• When decomposers break down dead bodies and waste, they make
it possible for the atoms in them to be reused by other organisms.
.
• For example, the worms in a compost heap break down dead
leaves.
• Molecules and atoms released from the dead leaves can be
used by new plants growing in the compost.
• The worms themselves get energy from the dead leaves.
• Birds or other animals can eat the worms, and get energy
themselves, as part of a food chain.
Summary
Decomposer are organisms that get their energy from
dead organisms or their waste products .
Decomposers help to recycle substances from dead
organisms and waste, so that other living organisms
can use them.
Multiple Choice
1.Decomposers help in 4.Decay is the breaking down or
(A) breaking dead waste
decomposition of
(B) recycle nutrients
(C) both a and b (A) waste matter
(D) spreading decay (B) birds
2. The most important group of decomposers
include (C) animals
(A) bacteria (D) Fish
(B) fungi
5.The rest of dead body left after
(C) both a and b
(D) virus
consumers feed is
3. Organisms which breakdown dead or waste (A) disappeared
matter in to simpler substances are termed as
(B) decomposed
(A) producers
(B) consumers (C) reacted
(C) decomposer (D) spread
(D) scavengers
1. A decomposer?
A. break down dead plants or animals to put nutrients in the soil
B. Eats plants or other animals for food
C. Makes its own food
D. Machine that gathers trash
1. In an ecosystem, decomposers break down ___ wastes
1. From where does the decomposer receive energy?
a) Producers
b) Consumers
c) Self generation
d) Organic substrates
Answer: a
Clarification: Decomposers receive energy by using organic substrates to get their energy,
nutrients for development and growth. Decomposers are organisms that break down dead and
decaying organisms. Similar to herbivores and predators, decomposers are also heterotrophic.
2. How many major groups classified in decomposers?
a) One
b) Two
c) Three
d) Four
Answer: b
Clarification: Decomposers can be classified into two group namely, fungi and detritivores. Fungi
break down deceased organism. While detritivores are responsible for consuming large particles
off the deceased organism.
Which are known as most recognized players in the food chain and energy puramid?
a) Producers
b) Consumers
c) Decomposers
d) Detritivores
Answer: c
Clarification: Decomposers are the most recognized players in the food chain and energy pyramid.
They are the only players that have direct access to the energy which is stored in plants that comes
from direct sunlight. It help in decay and in the conversion of remains of plants animals to carbon
dioxide and energy.
4. What is called for an organism which breakdown dead or waste matter into simpler substances?
a) Decomposers
b) Producers
c) Insects
d) Consumers
Answer: a
Clarification: Decomposers breakdown dead plant and animals. Decomposers are very important for
any ecosystem. If decomposers doesn’t exist then the plants would not get essential nutrients and even
dead and waste matter would pile up.
5. The primary decomposers of most dead plant material
are____________________
a) Algae
b) Bacteria
c) Fungi
d) Insects
Answer: c
Clarification: Fungi play a major role as decomposers and recycles in the wide
variety of habitants in which they exist. They release nitrogen and phosphorous
from decaying matter. In fungi we can see digestion precedes ingestion.
CQ 1:
Decomposers help in
breaking dead waste
recycle nutrients
both a and b
spreading decay
MCQ 2:
The most important group of decomposers include
bacteria
fungi
both a and b
virus
MCQ 3:
Organisms which breakdown dead or waste matter in to simpler substances are termed as
producers
consumers
decomposer
scavengers
MCQ 4:
Decay is the breaking down or decomposition of
waste matter
birds
animals
fish
MCQ 5:
The rest of dead body left after consumers feed is
disappeared
decomposed
reacted
spread
