Ecology PRA

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Unit IV: EcologyBCEE 2012Prepared by

Prashant Adsul, SKN SITS Lonavala


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What is an ecosystem?

Ecosystem is a system of livingthings that interact with each other

and with the physical world.

The collection of organisms in an

area along with the importantenvironmental factors


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Organization of Life

Organisms

Populations

Communities

Ecosystems

Biosphere


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Community

All the animals

and plants

living in anecosystem


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Population

A population is the

number of

organisms of thesame species living

in a habitat


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Habitat

The area where

animals and plants

live

Eg ocean habitat

Or.. More specificCoral habitat


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Main Ecosystems:

Natural- (e.g. lake, forest, grassland, etc.)

Man-made- (e.g. crop field, aquaria, etc.)

temporary- (e.g. rain-fed pond)

Permanent- (e.g. lake, forest, etc.)

Aquatic- (e.g. pond, ocean, etc.)

-Fresh water (e.g. ponds, lakes)-Salt water (e.g. marine, estuaries, etc)

Terrestrial (e.g. grassland, forest, etc.)


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An ecosystem can be as large as the

Sahara Desert, or as small as a puddle!!!

Ecosystems are more than just theorganisms they contain.

Geography, weather,climate and geologic

factors also influence the interactionswithin an ecosystem.


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Components of Ecosystem

Aboitic

Biotic


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Biotic Component

Living organisms in the ecosystem

variousspecies ofplants and animals including microbesare termed as biotic components.

They can be classified as producers (autotrophs)and consumers ( heterotrophs).

Autotrophs produce their own food from inorganic substances,

using light or chemical energy e.g plants

The heterotrophs do not have the ability to produce their own food.All these species are consumers. E.g. Bacteria


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Trophic Relationships

Autotrophs

1st level consumers (herbivores)

2nd

level consumers 3rd level consumers

4th level consumers (top predators)


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Balanced Ecosystem????

In the natural environment a balance or

equilibrium exists among various organisms

and abiotic components. This condition isknown as ecological balance, and the system is

called as BalancedEcosystem.


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Classification of Ecosystems / Ecology

Natural Ecosystem

Artificial Ecosystem

Terrestrial Ecosystems which encompass the activitiesthat take place on land,

Terrestrial ecosystem - Forest ecosystem,

Mountain ecosystem

Desert ecosystem

Grassland ecosystem

Urban ecosystem


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Classification of Ecosystems / Ecology

Aquatic ecosystems - the system that exists in waterbodies

Marine ecosystemFresh water ecosystem

Engineered ecosystem :An ecosystem which is fully

designed and controlled by man is called Engineeredecosystem. A paddy field or a fish pond can

be quoted as an example for this ecosystem


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Aquatic Ecosystem


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Food Chains

The producers, consumers, and

decomposers of each ecosystem make up

a food chain. There are many food chains in an

ecosystem.

Food chains show where energy istransferred and not who eats who.


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Food Chain

F d W b


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Food WebsAll the food chains in an area make up the food web of the area.


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RULE OF 10

Only 10% of energy is transferred from one

trophic level to the next.

Example:

It takes 100 kgs of plant materials (producers) to

support 10 kgs of herbivores

It takes 10 kgs of herbivores to support 1 kg of 1st

level predator


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Grassland Ecosystem

Climate is cool to cold in winter and hot in summers

Abiotic components- inorganic and organicsubstances present in soil and atmosphere

Biotic components-

Producer- herbaceous plant cover and variety ofgrasses such as Dicanthium, Imparata,Saccharum, etc.

Primary- Harbivores such as cows, buffalos, deer,

sheep, rabit, mouse etc. feeds on leaves ofGrasses


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Secondary- Carnivores such as Snakes, Birds,

lizards, fox, etc. feeds on harbivores

Tertiary- mainly HawksDecomposers- fungi, bacteria


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Desert Ecosystem

Characterised by very low rainfall ( less than 25 mm)

Abiotic components- poor nutrient cycle

Biotic components-

Producer-These includes shrubs, bushes, some

grasses and cactus

Consumers- insects, reptiles, birds, camel etc.Decomposers- Some fungi and bacteria with

actinomycetes

Dugn BeetleGerbill/ Greatindian bustard

Peregreen falcon


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Aquatic Ecosystem

Ranging from small puddles to large oceans.

Tertiaryconsumers

(Bird and prey)

Secondaryconsumer

Primary consumer (Trout)

Primary Producer (Micro organism)

Producers (plankton)


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Pond or Lake ecosystem

Abiotic components- inorganic and organicnutrients present in the water, such as C, H, O,N, P, S, Ca, apart from temp, light and water.

Biotic components-

Producers- plankton, macrophytes.

Consumers-

Primary consumers- zooplanktons

Secondary Consumers- insects and Fish

Tertiary Consumers- Large fish

Decomposers- Some fungi and bacteria withactinomycetes


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River or Stream Ecosystem

Sufficient oxygen must be present

Abiotic components- light and Fresh water.Biotic components-

Producers- Green algae, phytoplankton and

water grasses.

Consumers- water insects, snails, fishes and

crocodiles

Decomposers- Various microorganisms including

fungi and bacteria


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Ocean or Marine Ecosystem

Cover more than 2/3rd area of earth surface

These characterised by high concentration of salts andmineral ions.

Abiotic components- salinity, temp, light, dissolved

oxygen and other abiotic components.

Biotic components-

Producers- phytoplankton and large marine plants

Consumers-Primary consumers- Crustaceans, fish.

Secondary Consumers- Fish such as Herring, Mackerel.


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Tertiary Consumers- Large fish like cod, Shark etc

Decomposers- fungi and bacteria.

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Ecology PRA