forest ecosystem (terrestrial...

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


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.


Ecosystem = An Ecological system


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


EVS Videos/Ecology Introduction.mp4

../../Videos/3.1 Ecology Introduction.mp4











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


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


On the basis of particular type of habitat, they are divided as:

Various Types of Ecosystems


Terrestrial Ecosystem

Forest

Grassland

Desert


Fresh

Water

• Running water

• Streams, Rivers

• Standing water

• Lakes, ponds

Marine

Water

• Deep sea

• Oceans

Aquatic Ecosystem


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


Examples of Producers

Grasses

Shrubs

Trees


Examples of Consumers

Herbivores


Carnivores


Omnivores


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.


“ 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


Food web Interlocking pattern of several interlinked food chains is

termed as FOOD WEB.


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


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


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


Three stages-

1. Pioneer stage

2. Serial stage

3. Climax stage

E.g. Pond Ecosystem

Ecological Succession


Examples of Primary

Succession


Example of Secondary Succession


Various Ecosystems


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?


Forest Ecosystem

(Terrestrial Ecosystem)


Forest Ecosystem In India, the forest cover is roughly 19% of the total

land area.

It provides numerous environmental services.

Forest Ecosystem


Apart from environmental values, forest ecosystems

have some traditional values as well.

Products:-

Fire Wood & Timber.


Fruits.


Gums and resins.

Herbs & drugs.


Components of a Forest Ecosystem

Biotic components:

1) Producers

2) Consumers

3) Decomposers

Abiotic components:

Basic inorganic & organic compounds

present in the soil & atmosphere.


Components of Forest Ecosystem

Producers: Different tree species

Consumers in a Forest Ecosystem

Decomposers in a Forest ecosystem


Types of Forests in India Coniferous Forests

Himalayan mountain region


Evergreen Forests

Western Ghats, north-eastern India


Deciduous Forests

Moderate seasonal rainfall


Thorn Forests

Semi-arid regions


Mangrove Forests

Along the costal regions


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


Threats


Over-utilization

Population Growth

Urbanization

Industrialization

Mining

Dams

Poaching

Grassland Ecosystem



Grassland Ecosystem

EVS Videos\Tropical Grassland Ecosystems.mp4


EVS Videos/Tropical Grassland Ecosystems.mp4












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)


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.


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.


3) Decomposers:

These include Bacteria; Fungi.

Attack the dead or decayed bodies of organisms & thus

decomposition takes place.

Nutrients are released for reuse.


Components of Grassland Ecosystem

Producers

Consumers

Decomposers


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


Grassland utilization

Grazing

Thatching of houses and farm sheds

Fuel wood

Carnivorous animals control insect pests in

agricultural lands


Threats to Grassland Ecosystem

Lightening / Fire

Over grazing

Conversion to irrigated farmlands

Modification by Human activities


Desert Ecosystem



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


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.


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.


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.


Components of Desert Ecosystem

Producers

Consumers


Desert Utilization

Grazing for camel, cattle, goat etc

Growing crops like Jowar

Genetic Engineering


Threats to Desert Ecosystem

Extensive irrigation systems

Saline region due to water evaporation

Lowering in water tables


Conservation of Desert Ecosystem

Traditional protection

E.g. Bishnoi Tribes for Khejdi Trees

National parks and wildlife sanctuaries.

Aquatic

Ecosystems


Aquatic Ecosystem

EVS Videos\3.2 Aquatic Ecosystems.mp4


EVS Videos/3.2 Aquatic Ecosystems.mp4














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.


Biotic components:

1) Producer Organisms:

Includes submerged, free floating and amphibious

macrophytes (Hydrilla) and minute floating and

suspended lower phytoplankton's (Spirogyra)


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.


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.


Inside Ocean Ecosystem


Aquatic utilization

Clean fresh water for drinking

Fish used as food

Storage of water for industries and

agriculture

Electricity generation


Threats to Aquatic Ecosystem

Poorly managed solid waste

Eutrophication

Chemical pollution from industry


Conservation of Aquatic Ecosystem

Stop water pollution

Protection by including them in wetland

sanctuaries or national parks

Energy flow in ecosystem


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.


Photosynthesis - Chemical reaction where green plants

use water & carbon dioxide to store the sun’s energy in

glucose.


Energy contained within producers and consumers

is passed to the decomposers that are responsible

for the constant recycling of nutrients.


Energy Cycles

Water cycle

Carbon cycle

Oxygen cycle

Nitrogen cycle


The Water Cycle


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.


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.


The process of evaporation from plants is

called transpiration.

(In other words, it’s like plants sweating.)


http://www.dnr.state.wi.us/org/caer/ce/eek/earth/groundwater/images/trans.gif

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.


http://www.bigfoto.com/sites/galery/sky/08_sky-clouds-x.jpg

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.


http://www.jupiterimages.com/itemDetail.aspx?itemID=23147209


http://www.epa.gov/region7/kids/images/wtrcycle.gif

The Nitrogen Cycle


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.


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


The Carbon Cycle


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.


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.


Carbon Cycle

DEATH FOOD

BURNING

COMBUSTION

RESPIRATION

PLANTS

ANIMAL RESPIRATION

WOOD FOSSIL

FUEL

AIR CO2


Mr. S. P. Deshmukh, Watumull Institute. 93

Thank You…

Mr. S. P. Deshmukh, Watumull Institute. 94

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