Food chain and Food web
Food chain and Food web
Food chain
} Food chains are unidirectional
sequence or order of organisms
of an ecosystem that the food is passed from one type of organism to other
organisms.
} All trophic levels in an ecosystem
are connected by transferred of energy.
} Trophic level- The trophic
level of an organism is the position it occupies in a food chain. Energy flow of a food chain is
unidirectional i.e. From producer through herbivores to carnivores.
} The amount of energy flow decreases
with successive trophic level. A large amount of energy (~90%) is lost each
trophic level.
} Only about 10% of biomass is
transferred from one trophic level to the next one in a food chain.
Type of food chain-
Grazing food chain
} Grazing food chain starts from
plants, goes through herbivores and ends in carnivores.
example:
Grass à
Grasshopper à
Lizard à
Hawk
Phytoplankton à Zooplankton à Fish à Snake
} The grazing food chain is divided
into 2 type:
i.
Predator
ii.
Parasitic
 |
| Grazing Food Chain |
Detritus food chain
} Detritus food chain starts from dead
organic matter and ends in inorganic compound.
} Detritivores are certain groups of
organisms which feed exclusively on the dead bodies of organism.
Example of Detritus food chain:
} Leaf litterà Algae àCrabs à Small fish à Large fish
(Mangrove
Ecosystem)
} Dead Organic Matter à Fungi à Bacteria
(Forest
Ecosystem)
 |
| Detritus food chain |
Food web
} In nature, each organism may obtain
food from more than one tropic level. So food chains are found interconnected
and usually form a complex network known as food web.
} Food web is a network of food
chains.
} In food web organisms have a number
of options of eating and being eaten at each trophic level.
 |
| Food Web |
Significance of food chain and food web
} Play significance role in Energy
flow and Nutrients Cycling.
} Maintain Ecological Balance or
Stability of the Ecosystem.
} Biological magnification of some
chemicals.
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