Food chain and Food Web Food chain and food web in ecosystem Food chain Types of food chains 1. Grazing food chain 2. Detritus food chain Food web Significance of food chain and food web

1. Food Chain and
Food Web
in Ecosystem

2. Content –
 Food chain
 Types of food chains
1. Grazing food chain
2. Detritus food chain
 Food web
 Significance of food chain and
food web

3.  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.

4.  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.

5.  Grazing food chain starts from plants, goes through
herbivores and ends in carnivores.
example:
Grass  Grasshopper  Lizard  Hawk
Phytoplankton  Zooplankton  Fish  Snake
 The grazing food chain is divided into 2 type:
i. Predator
ii. Parasitic

6. Figure: Grazing food chain
Grass
Grasshopper
Frog
Snake
Hawk

7.  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 litter Algae Crabs  Small fish  Large fish
( Mangrove Ecosystem)
Dead Organic Matter  Fungi  Bacteria
( Forest Ecosystem)

8. Figure 2: Detritus food chain
Dead Leaves Woodlouse Black Bird

9.  In nature, each organism may obtain food from more
than one trophic 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.

10. Figure : Food Web

11.  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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