Intrtoduction Ecosystem

7/28/2019 Intrtoduction Ecosystem

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What is an Ecosystem?

Term proposed by British ecologist A. G. Tansley in

1935.

An Ecosystem is a Natural unit.

Consisting of all Plants, Animals and Micro- organisms

in an area functioning together with all the physical &

chemical (soil, climate, water and light) factors of the

environment.

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.


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Ecosystem = an Ecological system;

= A community and its physical environment

treated together as a functional system.


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Definition

A group of organisms interacting among themselves

and with environment is known as ecosystemAn ecosystem is a community of different species

interacting with one another and with their non-living

environment exchanging energy and matter

Ecology :

It's the study of ecosystem


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Types of Ecosystem:

The kind of organism which can live in a particular

ecosystem depends on their physical and metabolic

adaptations to the environment.

On earth there are many set of ecosystems within

a geographical region which are exposed to sameclimatic conditions & having dominant species with

similar life cycle, climatic adaptations and physical

structure.

This set of ecosystems is called BIOME

In the Biosphere, there are Natural & Artificial

biomes.


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ECOSYSTEM

Natural

Terrestrial

Aquatic

Marine

Fresh water

Lotic or Runnig water

Lentic or Standing water

Artificial / Man engineered


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Natural Biomes (Ecosystems):

Natural ecosystems operate by themselves under

natural conditions without interference of man They carry out many functions for us.

Wastewater is converted to drinkable water by

filtration through natural ecosystems, such as soils. Air pollutants from industries & automobiles are often

trapped on leaves or converted to harmless compounds

by forests.


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On the basis of particular type of habitat, theyare further sub divided as:

Terrestrial Ecosystems (Biomes): They are often defined by the land & vegetation

types that dominate the community.

Terrestrial vegetation has a rapid exchange ofoxygen, water & carbon dioxide.

Moisture is the major limiting factor, faces theproblem of dehydration.

Extremes of temperature are more pronounced.

Soil acts as highly developed ecologicalsubsystem.


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Examples of terrestrial ecosystem are:

Forest ecosystem.

Grassland ecosystem

Desert ecosystem.

Aquatic Ecosystems (Biomes):

Aquatic ecosystems deal with biotic community present in

water bodies. Aquatic organisms have the same basic needs as the

terrestrial organisms

However difference lies in the form in which they are made

available to them. In terrestrial ecosystem, carbon dioxide and oxygen are

present in gaseous form, but in aquatic ecosystem these are

made available in dissolved state.


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Aquatic ecosystems fall into two categories:

Freshwater Ecosystem and MarineEcosystem.

Freshwater ecosystem may be:

Lotic (Running water)

Example: Streams, Rivers, Springs

Lentic (Standing water)

Examples: Lakes, ponds, swamps

Marine ecosystems includes

Deep sea and Oceans.


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Man-made or Artifical Ecosystems (Biomes):

- Operated or maintained by man himself

- Ex: Cropland, gardens

Structure or Components of Ecosystem

The Structure or Components of Ecosystem

explain the relationship b/w the abiotic andbiotic components

Two major components

Abiotic components

biotic components


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Abiotic components:

Abiotic components are non - living (chemical &physical) factors an eco system collectively form acommunity

They practically provides all the energy for ecosystems.

Ex: Climate, soil, water, air, energy, nutrients, etc,..

They are of two forms:(i) Physical components:(energy, climate, raw materialand space)

Useful for growth and maintance of its member

Air, water, soil, sunlight, etc.(ii) Chemical components:( organic & inorganic)

Protein, lipids, carbohydrates, all micro (Al, Co, Zn,

Cu) & macro elements (C, H, O, P, N, P, K)


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Biotic components:

Biotic components refer to the living world of an

ecosystem.They are in entirety, any living component that

affects another organism.

They are of two forms:

Autotrophic: Organisms that produce their own food from an energy

source, such as the sun, and inorganic compounds.

They are also called PRODUCERS( member of thiscomponents)

Examples; Green Plants, algae, bacteria, etc.


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Heterotrophic:

Organisms that consume other organisms as a

food source.

Examples: Cows; Lions; Vultures


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Structure of an Ecosystem:

Ecosystem can be described according to its Trophic structure.

The trophic structure constitutes the levels of feeding (trophic= food) and the feeding relationships of the components of theecosystem.

Trophic structure is the pattern of movement of energy andmatter through an ecosystem.

All ecosystems must be based upon Autotrophs.

Autotrophs (Self feeders) produce organic food for themselvesand all members of their community.

The green plants (with chlorophyll) & certain bacteria producefood.

Since these organisms produce food for all the other organisms,they are known as Producers


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Autotrophs (Greek; auto = self & trophe = nutrition) take energyfrom the environment in the form of sunlight or inorganicchemicals and use it to create energy-rich molecules such

as Carbohydrates.

Green plants & photosynthtic bacteria are able to do this bymeans ofPhotosynthesis, where the sun provides the necessaryenergy.

Therefore these green plants are the autotrophic organisms or

primary producers in most ecosystems.
http://en.wikipedia.org/wiki/Carbohydratehttp://en.wikipedia.org/wiki/Carbohydrate


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Examples of producers:

Photosynthetic Bacteria Grasses Shrubs

Trees


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A Heterotrophs (Greek; heteros = another & trophe = nutrition)

are an organisms that uses organic substrates to get its chemical

energy for its life cycle.

It is the component in which utilization, rearrangement & breakdown of complex organic substances predominate.

They are dependant upon autotrophic organisms.

The members (organisms) of heterotrophic component are called

Consumers The heterotrophs are further categorized as:

Macro- Consumers:

Heterotrophs, which in an order as they occur in a food chain

are:


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1) Herbivores: Also primary consumers, feed directly on living plants

or plant residues. They have vegetarian diet.


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2) Carnivores: Also secondary/ tertiary consumers, which feed on

consumers, i.e. they have non- vegetarian diet.

They are also called Predators


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3) Omnivores: Consumers, which feed on producers as well as on

primary consumers, i.e. they have vegetarian as well as non-

vegetarian diet.


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Micro-consumers: Also Saprotrophs/ Detritivores . They are

popularly known as decomposers, such as bacteria, fungi,

flagellates & actinomyctes.

They feed on organic compounds of dead or living protoplasm ofplants and animals for their food and energy

They absorb some of the decomposition or breakdown products &

release inorganic compounds (nutrients) in the ecosystem, making

them available again to producers.


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In simple words, structure of an ecosystem means:

The composition of biological community

including species, population, biomass, lifehistory.

The quantity & distribution of abiotic materials

The range of conditions of existence, such astemperature, light, humidity, wind, wave action

etc.


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All organisms must obtain a supply of energy and

nutrients from their environment in order to survive.

The transformations of energy in an ecosystem begin

first with the input of energy from the sun.

Because, it is the first step in the production of energy

for living things, it is called Primary production.

Photosynthesis -- Chemical reaction where green plantsuse water & carbon dioxide to store the suns energy in

glucose.

ENERGY is stored in glucose.

Glucose is stored as starch in plants


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Energy flow cannot occur in reverse direction.

Starts from autotrophic (the producer level, i.e., first trophiclevel) to Heterotrophic including plant eaters or Herbivores

(second trophic level) and so on.

The amount of energy decreases with successive trophic

levels.

Only About 1% of energy from the sun is used by green

plants & rest remains unutilized.

Similarly, there is loss of energy in each trophic level.


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Intrtoduction Ecosystem