2. eco system definition and concept, structure

8/2/2019 2. Eco System Definition and Concept, Structure

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- Structure and Function


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Ecology and Ecosystem

The term Ecology was coined by Earnst Haeckel in 1869.

Derived from the Greek words

Oikos- home

logos- study

Deals with the stud of or anisms and interactions with

their surroundings.

The surroundings or environment consists of other living

organ sms ot c an p ys ca a ot c components.


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I. An ecosystem is a group of biotic communities of species

interacting with one another and with their non-livingenvironment exchanging energy and matter.

II. An ecos stem is an inte rated unit consistin of

interacting plants, animals and microorganisms whose

of their biotic and abiotic structures and functions.


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ECOSYSTEM STRUCTURE & FUNCTIONECOSYSTEM STRUCTURE & FUNCTION

BIOTICBIOTIC ABIOTICABIOTIC FUNCTIONALFUNCTIONAL

ProducersProducers PhysicalPhysical ChemicalChemical Food chains &WebsFood chains &Webs

ConsumersConsumers Light IntensityLight Intensity Energy FlowEnergy Flow

DecomposersDecomposers emperatureemperature

yc ng oNutrients

yc ng oNutrients

Atmosphere/windAtmosphere/wind

ProductivityProductivity

FireFire


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STRUCTURAL FEATURES

.

Includes plants, animals and microorganisms

Status in the ecosystems

The biotic com onents include

(a) Producers:

Primarily green plants, also include some kinds of microbes

synthesize their food by the process of Photosynthesis (Blue green algae,

cyanobacteria)

Also called as Photo autotrophs (auto=self; troph=food, photo=light).

Some microorganisms produce organic matter through oxidation of chemicals

known as chemosynthetic organisms or chemoautotrophs Ex: Sulphur bacteria


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Different colors around the edge of the pool come

y s a a v atemperatures and acidity.


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(b) Consumers

.

ii. Consumers include the following types:

Herbivores lant eaters :

Feed directly on producers

also known as primary consumers.

e.g. rabbit, insect, man.

Carnivores (meat eaters)

They feed on other consumers

If they feed on herbivores they are called secondary consumers

(e.g.frog)

If they feed on other carnivores they are known as tertiary

carn vores consumers.

(snake, big fish etc.)


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Omnivores

They feed on both plants and animals(Producers and consumers)

e.g. humans, rat, fox, many birds.

Detritivores (Detritus feeders or Saprotrophs)

They feed on dead organisms

wastes of living organisms and partially decomposed matter e.g.

beetles, termites, ants, crabs, earthworm, etc.

(c) Decomposers

Derive their nutrition b breakin down the com lex or anic

molecules to simpler molecules

organic compounds

Various bacteria and fungi are decomposers


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Herbivores Carnivores


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Detritivores


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ABIOTIC COMPONENTS OF ECOSYSTEM

Light Intensity

The radiant energy from the sun is the basic re uirement for the

existence of life on the earth.

This source of energy is of fundamental importance to the

photosynthetic production of food by plants

Light Intensity is not a lethal ecological factor

Illumination or Light intensity is measured in lux

The life on earth is related to the following radiations

i. Infra-red radiation

ii. Visible light

. trav o et ra at on


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Temperature The essential and changeable environmental factor.

Penetrates into every region of the biosphere and influences

all forms of life

Causes increasing or decreasing some of the vital activities

a. behaviour

b. metabolism

c. Reproduction

d. death.

Optimum temperature or the optimum range of temperature.

Organisms react to any rise or fall of the optimum temperature range

Temperature is a measure of the intensity ofheat

Expressed as degrees on either the Fahrenheit or Celsius scale


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Precipitation.

The moisture falling on an area in liquid, or frozen form

Includes all moisture that comes to earth in the form of rain, snow, hail and dew.

e c e source o so wa er

Water cycle or Hydrological cycle

, ,

Result of the cooling and condensation of water vapour at high altitudes.

The low tem erature at hi h altitudes cools the air which ets saturated and

loses its water-holding capacity.

As the temperature starts falling, the water vapour condenses and falls as rain

due to gravity.

Depending on the environmental conditions, precipitation falls as hail, snow or rain


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Fire

.

More common in drier habitats than the wet.

Li htenin is the commonest natural cause of fire initiation.

Our earths surface is hit by lightening every second in one or

another part of the globe and many of these are of great magnitude.

Falling rocks and dried woods

Volcanoes

Imp role in mineral and elemental recycling


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WIND FACTOR

The strong moving current of air is

An important ecological factor of the atmosphere

Transpiration

aus ng severa ypes o mec an ca amage

Dissemination of pollen, seeds and fruits

The pressure differences are mainly due to differential heating of atmosphere

Air enerall moves from oles towards e uator

Formation of cyclones, tornados, etc


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2. eco system definition and concept, structure

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