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Decomposition
Prof. Dr. Asrar M. Khan
Decomposition
• In biology, decomposition refers to the reduction of the
body of a formerly living organism into simpler forms of
matter.
• Decomposition or rotting is the process by which
tissues of a dead organism break down into simpler
forms of matter. The process is essential for new growth
and development of living organisms because it recycles
the finite matter that occupies physical space in the
biome.
• Bodies of living organisms begin to decompose shortly
after death. It is a cascade of processes that go through
distinct phases. It may be categorized in two stages by
the types of end products.
Decomposition
• It may be categorised in two stages by the types of end
products. The first stage is characterized by the
formation of liquid materials; flesh or plant matter begin
to decompose.
• The second stage is limited to the production of vapors.
• The science which studies such decomposition generally
is called taphonomy from the Greek word taphos, which
means grave.
• Historically the progression of decomposition of the flesh
of dead organisms has been viewed also as four phases:
Decomposition
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fresh (autolysis),
bloat (putrefaction),
decay (putrefaction and carnivores) and
dry (diagenesis).
In biology autolysis or more commonly known as self
digestion refers to the destruction of a cell through the
action of its own enzymes. It may also refer to the
digestion of an enzyme by another molecule of the
same enzyme. The term derives from the Greek words
αυτό ("self") and λύσις ("splitting").
Decomposition
• Autolytic cell destruction is uncommon in living adult organisms and
usually occurs in injured cells or dying tissue.
• Autolysis is initiated by the cells' lysosomes releasing the digestive
enzymes they contain out into the cytoplasm.
• The cell then, in effect, starts to digest itself. Autolysis of individual
cell organelles can be lessened if the organelle is stored in ice-cold
isotonic buffer after cell fractionation.
• Use
• Because primate fetuses grow webbed fingers and toes, autolysis
breaks down the webbing as they develop.
• Bread baking, winemaking etc.
Decomposition
• Lysosomes are spherical organelles that contain enzymes (acid
hydrolases). They break up food so it is easier to digest. They are
found in animal cells, while in yeast and plants the same roles are
performed by lytic vacuoles.
• Some important enzymes found within lysosomes include:
• Lipase digests lipids,
• Amylase digests carbohydrates, sugar
• Protease digests protein
• Nuclease digests nucleic acid and Phoshoric acid monoesters
• Lysosomes are the cells' garbage disposal system. They are used
for the digestion of macromolecules from phagocytosis (ingestion of
other dying cells or larger extracellular material, like foreign invading
microbes),
Decomposition
• Decomposition of plant matter occurs in many stages. It
begins with leaching by water; the most easily lost and
soluble carbon compounds are liberated in this process.
Another early process is physical breakup or
fragmentation of the plant material into smaller bits which
have greater surface area for microbial colonization and
attack.
• Decomposition begins at the moment of death, caused
by two factors: autolysis, the breaking down of tissues by
the body's own internal chemicals and enzymes, and
putrefaction, the breakdown of tissues by bacteria.
These processes release gases that are the chief source
of the unmistakably putrid odor of decaying animal
tissue.
Decomposition
• Humus is a complex organic substance resulting from
the breakdown of plant material in a process called
humification. This process can occur naturally in soil, or
in the production of compost.
• Humus is extremely important to the fertility of soils in
both a physical and chemical sense.
• In soil science, humus refers to any organic matter that
has reached a point of stability, where it will break down
no further and might, if conditions do not change, remain
essentially as it is for centuries, if not millennia.
Decomposition
• The rate and manner of decomposition in an animal
body is strongly affected by a number of factors. In
roughly descending degrees of importance, they are:
• Temperature, The availability of oxygen, Prior
embalming, Cause of death,
• Burial, and depth of burial, Access by
scavengers,Trauma, including wounds and crushing
blows, Humidity, or wetness, Rainfall
• Body size and weight, Clothing, The surface on which
the body rests
• Foods/objects inside the specimen's digestive tract