FOOD CHAIN
PREPARED BY:MARIA ISABEL HOOBEN
Lesson Outline
Food Chain
Food Web
Ecological Pyramids
Classifications of Ecosystem
In this lesson,
you'll learn to:
Differentiate food chains from food webs.
Differentiate the classifications of ecosystems.
Define producers and consumers.
Food Chain
A
food
chain
refers
ecosystem,
where
organism,
and
another
larger
energy
from
one
later
to
the
living
that
organism.
one
organism
order
organism
organism
The
to
of
flow
is
of
another
trophic levels forms a food chain.
events
in
an
eats
another
consumed
by
nutrients
and
at
different
TYPES OF FOOD CHAIN
Grazing Food Chain
Detritus Food Chain
Parasitic Food Chain
Sun
Grass
Caterpillar
Squirrel
Eagle
Grazing Food Chain
This food chain starts from living green plants to grazing
herbivores and carnivores. An ecosystem with such a food chain
directly depends on solar energy for its food requirements.
Most of the ecosystem in nature follows this type of food
chain.
Detritus Food Chain
This food chain goes from dead organic matter to
microorganisms and the organisms feeding on
detritus and their predators. Such ecosystems
are less dependent on direct solar energy.
Parasitic Food Chain
This type of food chain starts with big hosts and ends
with parasitic organisms.
Food Web
The interconnected, interlocking pattern of the food chain
is
known
linear
they
as
the
food
arrangement
remain
of
web.
Under
natural
the
food
chain
interconnected
with
conditions,
hardly
each
occurs
other
the
and
through
different types of organisms at different levels Such an
interconnected and interlocking pattern of the food chain
is known as the food web...
Example of Food Web
Ecological Pyramids
The different species in a food chain are
called tropic levels. Each food chain has 3
main trophic levels, producer, consumer, and
decomposer. Thus Graphical representation of
these trophic levels is called an Ecological
Pyramid. It was devised by an ecologist
“Charles Elton” therefore this pyramid is
also
called
the
Ecological
Pyramid
or
Eltonian pyramids.
The pyramid is formed based on the number of
organisms, energy, and biomass, and just like
the name suggests, these are shaped in the
form of a pyramid.
TYPES OF ECOLOGICAL PYRAMIDS
1. Pyramid of Number
2. Pyramid of Biomass
3. Pyramid of Energy
Pyramid of Number
The pyramid of numbers illustrates the relationship between
producers, herbivores, and carnivores in an ecosystem based on
their population sizes. In pond ecosystems, where phytoplankton
dominate, the pyramid is upright due to their high numbers.
Conversely, in forest ecosystems, where large trees are fewer
but herbivores like fruit-eating birds are more numerous, the
pyramid is initially inverted but eventually becomes upright
again due to a decrease in secondary consumers. This indicates
that the pyramid of numbers may not always reflect accurate food
chain dynamics.
Pyramid of Number
Pyramid of Biomass
This
particular
representation
type
that
of
ecological
illustrates
the
pyramid
relative
is
amount
a
graphical
of
biomass
(living or organic matter) at each trophic level in an ecosystem
Typically, there's a gradual decrease in biomass from producers to
top
carnivores,
grassland
resulting
ecosystems.
in
an
upright
pyramid,
as
seen
in
However,
in
ponds,
where
algae
are
the
producers and least in number, the pyramid is inverted due to an
increase in biomass towards the top carnivores.
Pyramid of Biomass
Pyramid of Energy
An energy pyramid is a model that shows the flow of energy from
one trophic, or feeding, level to the next in an ecosystem. The
model is a diagram that compares the energy used by organisms at
each trophic level.
The shape of an energy pyramid shows that the amount of food
energy that enters each trophic level is less than the amount that
enters the level below. Approximately 90 percent of the food
energy that enters a trophic level is “lost” as heat when it is
used by organisms to power the normal activities of life such as
breathing and digesting food; the remaining 10 percent is stored
in the various organisms’ tissues. It is this latter energy that
is available to be passed to the next trophic level. Thus, the
higher the trophic level on the pyramid, the lower the amount of
available energy.
Pyramid of Energy
Classification of Ecosystems
Due
to
the
different
abiotic
ways.
factors,
These
factors
different
ecosystems
develop
and
interaction
with
their
in
each
other and with biotic components have resulted in the formation of
different types of ecosystems as explained below.
Ecosystems may be natural or artificial.
Artificial Ecosystem: These are maintained or created artificially
by man. The man tries to control the biotic community as well as
the physico-chemical environment. Eg: Artificial ponds, and urban
area development.
Natural
Ecosystem:
It
consists
of
Terrestrial
Ecosystems which are maintained naturally.
and
Aquatic
Ecosystem
Different Types of Ecosystem of
Biosphere Artificially Categorized
as follows:
I) Natural Ecosystems
These ecosystems operate by themselves under natural conditions
without any major interference by man. Based upon the particular kind
of habitat, these are further divided as:
• Terrestrial as forest, grassland, desert etc.
• Aquatic which may be further distinguished as - Freshwater which may
be lotic (running water such as springs, streams, rivers) or lentic
(standing water such as lakes, ponds, pools, ditches, swamps, etc.)
• Marine Ecosystems: as an ocean or shallow ones like sea or estuary
etc.
Natural Ecosystems
Terrestrial Ecosystem
Different Types of Ecosystem of
Biosphere Artificially Categorized
as follows:
II) Artificial Ecosystems
These are maintained by man where, by the addition of energy &
planned manipulations natural balance is disturbed regularly.
For eg : croplands like maize, wheat, rice-fields etc., where man
tries to control the biotic community as well as physico-chemical
environment are artificial ecosystems.
Artificial Ecosystems
Pond Ecosystem
A Pond as
ecosystem.
a
whole
serves
as
a
good
example
of
a
freshwater
Abiotic Components
The chief components are heat, light, pH of water, CO2, oxygen,
calcium, nitrogen, phosphates, etc.
Biotic Components
The various organizations that constitute the biotic component are
as follows,
• Producers: These are green plants, and some photosynthetic
bacteria. The producer fixes radiant energy and converts it into
organic substances such as carbohydrates, protein, etc
Macrophytes- these are large rooted plants, which include partly
or completely submerged hydrophytes. (eg Hydrilla)
Types of Aquatic Plants
Emergent
Submergent
Floating
Reed Leaves
Sea Grasses
Azolla
Water Primrose
Vallisneria
Phytoplankton- Obtain energy through the process of photosynthesis
and must therefore live in the well-lit surface layer.
PHYTOPLANKTON
Consumers
They are heterotrophs that depend for their nutrition on the organic
food manufactured by producers.
Primary Consumers
Benthos - These are the organisms that live at the bottom of a body
of water.
Zooplankton - These are tiny animals that drift in the water
currents of oceans, lakes, and rivers. They are essential for the
marine food web and the health of aquatic ecosystems.
Secondary Consumers
They are the Carnivores that feed on herbivores, these are chiefly
insects and fish, most insects & water beetles.
Example of Herbivore
Sheep
Elephant
Horse
Rabbit
Tertiary Consumers
These are some large fish as game fish, and turtles, which feed on
small fish and thus become tertiary consumers.
Decomposers
They are also known as microconsumers. They decompose dead organic
matter of both producers and animals to a simple form. Thus they
play an important role in the return of minerals again to the pond
ecosystem.
THANK YOU!
“In every other science fiction series, humans are
at the top of the food chain. In the 'Babylon 5'
universe, they're in the bottom third.”
-
John Michael Straczynski