Chapter 3
“Ecosystem”
1 Mr. S. P. Deshmukh, Watumull Institute.
Things to be learned…
Concept and Classification of Ecosystem
Structure and functions of Ecosystem
Producers, Consumers, Decomposers
Food chains, Food webs, Ecological pyramids
Various Ecosystems
Energy Flow & Energy Cycles
2 Mr. S. P. Deshmukh, Watumull Institute.
What is an Ecosystem?
Term proposed by British ecologist A. G. Tansley in 1935. Consisting
of all Plants, Animals and Micro- organisms
Specific and Recognizable landscape form.
An ecosystem is formed by the interactions between all living and
non-living things.
Eco = The Environment
System=Regularly interacting and interdependent components
forming a unified whole.
3 Mr. S. P. Deshmukh, Watumull Institute.
Ecosystem = An Ecological system
4 Mr. S. P. Deshmukh, Watumull Institute.
What is an Ecology?
The branch of biology that deals with the
relations of organisms to one another and to their
physical surroundings.
The study of the interaction of people with their
environment.
EVS Videos\Ecology Introduction.mp4
5 Mr. S. P. Deshmukh, Watumull Institute.
Fundamental Characteristics of Ecosystem
Structural
Living /Biotic
Non-living
/Abiotic
Inorganic components
Organic components
Climatic Regimes
Functional
Energy cycles
Food chains
Diversity
Nutrient cycles
Evolution
6 Mr. S. P. Deshmukh, Watumull Institute.
Structure:
Living/Biotic ( Plants, Animals and Micro-
organisms )
Non-living/ Abiotic (soil, climate, water and light )
Inorganic components - C,N,CO2
Organic components - Proteins, Fats
Climatic Regimes - Temp, Moisture
Macro and Micro consumers
7 Mr. S. P. Deshmukh, Watumull Institute.
On the basis of particular type of habitat, they are divided as:
Various Types of Ecosystems
8 Mr. S. P. Deshmukh, Watumull Institute.
Terrestrial Ecosystem
Forest
Grassland
Desert
9 Mr. S. P. Deshmukh, Watumull Institute.
Fresh
Water
• Running water
• Streams, Rivers
• Standing water
• Lakes, ponds
Marine
Water
• Deep sea
• Oceans
Aquatic Ecosystem
10 Mr. S. P. Deshmukh, Watumull Institute.
Components of Ecosystem
Abiotic components:
1. Abiotic components are non - living chemical & physical factors in the environment.
2. They practically provides all the energy for ecosystems.
Biotic components:
1. Producers
2. Consumers
3. Decomposers
11 Mr. S. P. Deshmukh, Watumull Institute.
Examples of Producers
Grasses
Shrubs
Trees
12 Mr. S. P. Deshmukh, Watumull Institute.
Examples of Consumers
Herbivores
13 Mr. S. P. Deshmukh, Watumull Institute.
Carnivores
14 Mr. S. P. Deshmukh, Watumull Institute.
Omnivores
15 Mr. S. P. Deshmukh, Watumull Institute.
Decomposers Feed on organic compounds of dead or living plants
and animals for food and energy
Breakdown products & release inorganic compounds
(nutrients) in the ecosystem, making them available
again to producers.
16 Mr. S. P. Deshmukh, Watumull Institute.
“ The transfer of energy and nutrients through a
series of organisms with repeated process of eating
and being eaten”.
All the organisms are linked together with one
another by food relationship.
Each organism living or dead is potential food for
some other organism.
Food Chain
17 Mr. S. P. Deshmukh, Watumull Institute.
18 Mr. S. P. Deshmukh, Watumull Institute.
Food web Interlocking pattern of several interlinked food chains is
termed as FOOD WEB.
19 Mr. S. P. Deshmukh, Watumull Institute.
Ecological Pyramids
The relationship between producers, consumers and
decomposers at different tropic levels in an ecosystem.
Pyramid represents decrease in amount of energy, number of
organisms and biomass from producers to higher level
consumers.
Types of pyramid –
1. Pyramid of Energy
2. Pyramid of Numbers
3. Pyramid of Biomass
20 Mr. S. P. Deshmukh, Watumull Institute.
Grasses
Snakes, Frogs,
Birds etc.
Cows Sheep,
Deer, Rabbit
Trees
Lion, Tiger,
etc.
Elephant, Deer etc.
Carnivores
Herbivores
Producers
Phytoplankton's
Fish etc.
Zooplanktons
Carnivores
Herbivores
Producers
21 Mr. S. P. Deshmukh, Watumull Institute.
Grassland Ecosystem Forest Ecosystem
Pond Ecosystem
The occurrence of definite sequence of
communities over a period of time in same area.
A process through which ecosystems tends to
change, over a period of time
A change in the community in which new
populations of organisms gradually replace
existing ones.
Can be related to environmental changes.
Ecological Succession
22 Mr. S. P. Deshmukh, Watumull Institute.
Three stages-
1. Pioneer stage
2. Serial stage
3. Climax stage
E.g. Pond Ecosystem
Ecological Succession
23 Mr. S. P. Deshmukh, Watumull Institute.
Examples of Primary
Succession
24 Mr. S. P. Deshmukh, Watumull Institute.
Example of Secondary Succession
25 Mr. S. P. Deshmukh, Watumull Institute.
Various Ecosystems
26 Mr. S. P. Deshmukh, Watumull Institute.
Basic Things To Remember About Ecosystems-
What is the nature / type of an ecosystem?
What are its structure and functions?
Who uses the ecosystems and for what purpose?
How is ecosystem degraded?
What can be done to protect it from deteriorating
in the long time? How can the ecosystem be
conserved?
27 Mr. S. P. Deshmukh, Watumull Institute.
Forest Ecosystem
(Terrestrial Ecosystem)
28 Mr. S. P. Deshmukh, Watumull Institute.
Forest Ecosystem In India, the forest cover is roughly 19% of the total
land area.
It provides numerous environmental services.
Forest Ecosystem
29 Mr. S. P. Deshmukh, Watumull Institute.
Apart from environmental values, forest ecosystems
have some traditional values as well.
Products:-
Fire Wood & Timber.
30 Mr. S. P. Deshmukh, Watumull Institute.
Fruits.
31 Mr. S. P. Deshmukh, Watumull Institute.
Gums and resins.
Herbs & drugs.
32 Mr. S. P. Deshmukh, Watumull Institute.
Components of a Forest Ecosystem
Biotic components:
1) Producers
2) Consumers
3) Decomposers
Abiotic components:
Basic inorganic & organic compounds
present in the soil & atmosphere.
33 Mr. S. P. Deshmukh, Watumull Institute.
Components of Forest Ecosystem
Producers: Different tree species
Consumers in a Forest Ecosystem
Decomposers in a Forest ecosystem
34 Mr. S. P. Deshmukh, Watumull Institute.
Types of Forests in India Coniferous Forests
Himalayan mountain region
35 Mr. S. P. Deshmukh, Watumull Institute.
Evergreen Forests
Western Ghats, north-eastern India
36 Mr. S. P. Deshmukh, Watumull Institute.
Deciduous Forests
Moderate seasonal rainfall
37 Mr. S. P. Deshmukh, Watumull Institute.
Thorn Forests
Semi-arid regions
38 Mr. S. P. Deshmukh, Watumull Institute.
Mangrove Forests
Along the costal regions
39 Mr. S. P. Deshmukh, Watumull Institute.
Forest utilization
Maintenance of Nutrient cycles
Maintenance of biodiversity
Providing wildlife habitat
Affecting rainfall patterns
Regulating stream flow
Storing water
Reduced flooding
Prevention of soil erosion
40 Mr. S. P. Deshmukh, Watumull Institute.
Threats
41 Mr. S. P. Deshmukh, Watumull Institute.
Over-utilization
Population Growth
Urbanization
Industrialization
Mining
Dams
Poaching
Grassland Ecosystem
(Terrestrial Ecosystem)
42 Mr. S. P. Deshmukh, Watumull Institute.
Grassland Ecosystem
EVS Videos\Tropical Grassland Ecosystems.mp4
43 Mr. S. P. Deshmukh, Watumull Institute.
Occupy about 24% of the earth’s surface.
Occur in regions too dry for forests and too moist for
deserts
The principal grasslands include:
Prairies (Canada, USA)
Pampas (South America)
Steppes (Europe & Asia)
Veldts (Africa)
44 Mr. S. P. Deshmukh, Watumull Institute.
Components
Abiotic components: Include basic inorganic & organic compounds present in the
soil & aerial environment.
Essential elements like C, H, N, O, P, S etc. supplied by
water, nitrogen, nitrates, sulphates, phosphates present in
soil & atmosphere.
Biotic components: Three functional groups which are:
1) Producers:
Mainly grasses; though, a few herbs & shrubs also
contribute to primary production of biomass.
45 Mr. S. P. Deshmukh, Watumull Institute.
2) Consumers:
a) Primary Consumers:
Herbivores feeding directly on grasses.
Grazing animals such as-
• Cows, Buffaloes, Sheep, Goats, Deer, Rabbits etc.
• Besides them, numerous species of insects, termites, etc are
also present.
b) Secondary Consumers:
Carnivores that feed on primary consumers (Herbivores)
These include-
• Frogs, Snakes, Lizards, Birds, Foxes, Jackals etc.
c) Tertiary Consumers:
These include hawks etc. which feed on secondary consumers.
46 Mr. S. P. Deshmukh, Watumull Institute.
3) Decomposers:
These include Bacteria; Fungi.
Attack the dead or decayed bodies of organisms & thus
decomposition takes place.
Nutrients are released for reuse.
47 Mr. S. P. Deshmukh, Watumull Institute.
Components of Grassland Ecosystem
Producers
Consumers
Decomposers
48 Mr. S. P. Deshmukh, Watumull Institute.
Types Of Grasslands In India
1. Himalayan Pasture belt
2. Terai Grassland
Himalayan foothills
3. Semi-arid grassland
Western India, Central India and the Deccan
4. Shola grasslands
Western Ghats
Patches of hill slopes
49 Mr. S. P. Deshmukh, Watumull Institute.
Grassland utilization
Grazing
Thatching of houses and farm sheds
Fuel wood
Carnivorous animals control insect pests in
agricultural lands
50 Mr. S. P. Deshmukh, Watumull Institute.
Threats to Grassland Ecosystem
Lightening / Fire
Over grazing
Conversion to irrigated farmlands
Modification by Human activities
51 Mr. S. P. Deshmukh, Watumull Institute.
Desert Ecosystem
(Terrestrial Ecosystem)
52 Mr. S. P. Deshmukh, Watumull Institute.
Region that receives almost no precipitation.
Areas with an average annual precipitation of less than
250 millimeters per year.
Occupy about 17% of the earth’s surface.
The deserts of the world are mainly located in-
South- western United States,
Mexico,
North America,
Asia (Thar, Tibet )
West Asia
Desert Ecosystem
53 Mr. S. P. Deshmukh, Watumull Institute.
The various components of a Desert Ecosystem are:
Biotic components:
1) Producer Organisms:
Mainly shrubs ,bushes, some grasses & a few trees.
Dominant plant species include: Succulents (water
- retaining plants adapted to arid climate
or soil conditions ) & hardy grasses.
Besides some lower plants such as lichens &
xerophytes mosses are also present.
54 Mr. S. P. Deshmukh, Watumull Institute.
55 Mr. S. P. Deshmukh, Watumull Institute.
2) Consumer Organisms:
Includes animals such as insects, reptiles which
are capable of living in extreme conditions
Besides some nocturnal rodents, birds & some
mammalians like camel etc are also found.
56 Mr. S. P. Deshmukh, Watumull Institute.
3) Decomposers:
Due to poor vegetation with very low amount of dead organic matter, decomposers are poor in desert ecosystem.
Common decomposers are some bacteria & fungi, most of which are thermophillic.
Abiotic components:
Due to high temperature & very low rainfall, the
organic substances are poorly present in the soil.
57 Mr. S. P. Deshmukh, Watumull Institute.
Components of Desert Ecosystem
Producers
Consumers
58 Mr. S. P. Deshmukh, Watumull Institute.
Desert Utilization
Grazing for camel, cattle, goat etc
Growing crops like Jowar
Genetic Engineering
59 Mr. S. P. Deshmukh, Watumull Institute.
Threats to Desert Ecosystem
Extensive irrigation systems
Saline region due to water evaporation
Lowering in water tables
60 Mr. S. P. Deshmukh, Watumull Institute.
Conservation of Desert Ecosystem
Traditional protection
E.g. Bishnoi Tribes for Khejdi Trees
National parks and wildlife sanctuaries.
61 Mr. S. P. Deshmukh, Watumull Institute.
Aquatic
Ecosystems
62 Mr. S. P. Deshmukh, Watumull Institute.
Aquatic Ecosystem
EVS Videos\3.2 Aquatic Ecosystems.mp4
63 Mr. S. P. Deshmukh, Watumull Institute.
Aquatic Ecosystems
Deals with biotic community present in water
bodies.
Carbon dioxide & oxygen are available in dissolved
state.
Types of Aquatic ecosystem are:
1. Freshwater ecosystem includes- Running water
Example: Streams, Rivers, Springs
Standing water
Examples: Lakes, ponds, swamps
2. Marine ecosystems includes- Deep sea and Oceans.
64 Mr. S. P. Deshmukh, Watumull Institute.
Biotic components:
1) Producer Organisms:
Includes submerged, free floating and amphibious
macrophytes (Hydrilla) and minute floating and
suspended lower phytoplankton's (Spirogyra)
65 Mr. S. P. Deshmukh, Watumull Institute.
2) Consumer Organisms:
a) Primary consumers:
These are planktons and benthos.
b) Secondary consumers:
These are carnivores like insects and fishes feeding on herbivores
c) Tertiary consumers:
These are the large fishes feeding on small fishes.
66 Mr. S. P. Deshmukh, Watumull Institute.
3) Decomposers:
Micro – organisms like bacteria, fungi.
Abiotic component:
Inorganic as well as organic substances
present in the bottom soil or dissolved
in water.
The minerals, some dead organic
matter is also present.
67 Mr. S. P. Deshmukh, Watumull Institute.
Inside Ocean Ecosystem
68 Mr. S. P. Deshmukh, Watumull Institute.
Aquatic utilization
Clean fresh water for drinking
Fish used as food
Storage of water for industries and
agriculture
Electricity generation
69 Mr. S. P. Deshmukh, Watumull Institute.
Threats to Aquatic Ecosystem
Poorly managed solid waste
Eutrophication
Chemical pollution from industry
70 Mr. S. P. Deshmukh, Watumull Institute.
Conservation of Aquatic Ecosystem
Stop water pollution
Protection by including them in wetland
sanctuaries or national parks
Energy flow in ecosystem
71 Mr. S. P. Deshmukh, Watumull Institute.
Energy flow in ecosystem
Supply of energy and nutrients from
environment in order to survive.
The transformations of energy in an
ecosystem begin first with the input of energy
from the sun.
72 Mr. S. P. Deshmukh, Watumull Institute.
Photosynthesis - Chemical reaction where green plants
use water & carbon dioxide to store the sun’s energy in
glucose.
73 Mr. S. P. Deshmukh, Watumull Institute.
Energy contained within producers and consumers
is passed to the decomposers that are responsible
for the constant recycling of nutrients.
74 Mr. S. P. Deshmukh, Watumull Institute.
Energy Cycles
Water cycle
Carbon cycle
Oxygen cycle
Nitrogen cycle
75 Mr. S. P. Deshmukh, Watumull Institute.
The Water Cycle
76 Mr. S. P. Deshmukh, Watumull Institute.
Water never leaves the Earth.
It is constantly being cycled through the
atmosphere, ocean, and land.
This process, known as the water
cycle, is driven by energy from the sun.
77 Mr. S. P. Deshmukh, Watumull Institute.
78 Mr. S. P. Deshmukh, Watumull Institute.
The sun heats up liquid water and changes it to a gas
by the process of evaporation.
Water that evaporates from Earth’s oceans, lakes,
rivers, and moist soil rises up into the atmosphere.
79 Mr. S. P. Deshmukh, Watumull Institute.
The process of evaporation from plants is
called transpiration.
(In other words, it’s like plants sweating.)
80 Mr. S. P. Deshmukh, Watumull Institute.
As water (in the form of gas) rises higher in the
atmosphere, it starts to cool and become a liquid again.
This process is called condensation
When a large amount of water vapor condenses, it results
in the formation of clouds.
81 Mr. S. P. Deshmukh, Watumull Institute.
When rain falls on the land, some of the water is absorbed
into the ground forming pockets of water called
groundwater. Most groundwater eventually returns to the
ocean. Other precipitation runs directly into streams or
rivers. Water that collects in rivers, streams, and oceans is
called runoff.
82 Mr. S. P. Deshmukh, Watumull Institute.
The Nitrogen Cycle
84 Mr. S. P. Deshmukh, Watumull Institute.
Nitrogen cycle completes in 5 steps:-
1) Nitrogen Fixation:
Conversion of N2 → NH3
2) Nitrification: NH3 → NO3
Soil bacteria convert in a two step process.
3) Assimilation:
Roots absorb NH3, NH4, or NO3 and incorporate
them into nucleic acids and protein.
85 Mr. S. P. Deshmukh, Watumull Institute.
4) Ammonification:
Amino acids and nucleotides are broken
down into waste products NH3 or NH4
5) Denitrification:
The reduction of NO3 to N2 Denitrifying
bacteria return some of the nitrogen to the
atmosphere
86 Mr. S. P. Deshmukh, Watumull Institute.
87 Mr. S. P. Deshmukh, Watumull Institute.
The Carbon Cycle
88 Mr. S. P. Deshmukh, Watumull Institute.
Carbon enters plants as CO2
Bacteria process carbon in a fashion that
allows it to be recycled.
Obtain energy from the molecules, and
convert carbohydrates to carbon dioxide as a
result of respiration.
89 Mr. S. P. Deshmukh, Watumull Institute.
Photosynthesis removes carbon from the
abiotic environment
Carbon moves through food chain through
consumption of one organisms by another
Cellular respiration, combustion, and
erosion of limestone return carbon to the
atmosphere, water and abiotic
environment.
90 Mr. S. P. Deshmukh, Watumull Institute.
Carbon Cycle
DEATH FOOD
BURNING
COMBUSTION
RESPIRATION
PLANTS
ANIMAL RESPIRATION
WOOD FOSSIL
FUEL
AIR CO2
91 Mr. S. P. Deshmukh, Watumull Institute.
92 Mr. S. P. Deshmukh, Watumull Institute.
Mr. S. P. Deshmukh, Watumull Institute. 93
Thank You…
Mr. S. P. Deshmukh, Watumull Institute. 94