ecosystem enviromental studies

8/10/2019 Ecosystem enviromental studies

1/86

ECOSYSTEM


2/86

What is a Population? A population is one species

living in a specific area.

For example, all foxes living inan area form a population.

Another example, all rosesgrowing in an area form

another population.


3/86

What is a Community?

A community is formed from all livingpopulations found in an area.

All the foxes, roses, grasshoppers,snakes, hawks, deer, and skunksliving in one area each form their

individual populations, but togethermake up a community.


4/86

Living thingsin an

ecosystem arecalled a

COMMUNITY


5/86

Population

Population

+ Population

COMMUNITY


6/86

ECOSYSTEM:The concept of ecosystem was

first put forth by A.G.Tansley (1935).

Ecosystem is the major ecological unit. It hasboth structure and function .

The structure is related to species diversity.The more complex is the structure the

greater is the diversity of the species in theecosystem.

An organism is always in the state of

perfect balance with the environment. Theenvironment literally means the surrounding.


7/86

ECOSYSTEM:

The term ecosystem was first coined by A.GTansely.It consist of two Words.

Eco : EnvironmentSystem : Interaction

Thus

The ecosystem refers to thethings and conditions around the organism,which directly or influence the life anddevelopment of the organism and theirpopulations.


8/86

According to E.P.Odum , the ecosystem isthe basic functional unit of organism andtheir environment interacting with eachother and with their own components.

An ecosystem may be conceived and studiedin the habitat of various sizes, e.g. onesquare meter of grassland , a pool, a largelake balanced aquarium and a certain area

of river and ocean


9/86

All the ecosystems of earth are connected to one

another e.g. river ecosystem with ecosystem of

ocean.

STRUCTURE OF ECOSYSTEM:

The structure of an ecosystem is basically a

description of the organism and physical

features of the environment including theamount and distribution of nutrients in a

particular habitat.


10/86

It also provides information regarding the range of

climatic conditions prevailing in the area.

From the structural point of view , all ecosystemconsist of the following basic components:

Abiotic component

Biotic component


11/86

1. ABIOTIC COMPONENTS:

Ecological relationships are manifested inphysiochemical environment. Abioticcomponent of the ecosystem includes basicinorganic elements and compounds such assoil, water, oxygen, calcium carbonates,phosphates and a variety of organic activitiesor death.

It also includes physical factors and ingredientsas moisture, wind currents and solarradiation.


12/86

2. BIOTIC COMPONENTS:

The biotic components include all living

organisms present in the environmentalsystem.

From nutrition point of view , the bioticcomponents can be grouped into two basiccomponents.

Autotrophic components

Heterotrophic components


13/86

Herbivores: Plant Eaters

Carnivores:Secondary consumers and depend on herbivores

Omnivores:Eat everything, whatever is available

Scavengers: Dead material is eaten by them. Eg: Vulcher

(Vulchers are rare: due to pesticides)

Detritivores: Feed on parts of dead organisms

Decomposers: Bacteria and fungi, which recycle organicmatter and ecosystem by biodegradation and releasing the

resulting simpler inorganic compounds or water where theyare taken up as nutrients by producers.


14/86

1. AUTOTROPHIC COMPONENTS (Primary Producers) :

It includes all the green plants which fix the radiantenergy of sun and manufacture food from inorganicsubstances through photosynthesis.

2. HETEROTROPHIC COMPONENTS:

It includes green bacteria, non green plants and all

animals which take food from autotrophs . So, bioticcomponents of an ecosystem can be described underthe following three heads.

Secondary Producers

Consumers

Decomposers or reducers


15/86

a. Secondary PRODUCERS:

Photoheterotrophs, including most purple bacteria and green

bacteria, produce energy from light and use organiccompounds to build structures. They consume little or none ofthe energy produced during photosynthesis

They use radiant energy of sun in photosynthetic process. algae and other hydrophytes of a pond, grasses of afield, trees of the forests are example of producers.

b. CONSUMERS:

Those living members of the ecosystems which consumethe food synthesized by producers are called

consumers.under this category are included all different kinds of

animals that found in an ecosystem.

There are different classes of consumers, such as


16/86

Consumers of the first order or primary consumers

Consumers of second order or secondary consumers

Consumers of third order or tertiary consumers

Scavengers

I.CONSUMERS OF THE FIRST ORDER OR PRIMARYCONSUMERS:

These are purely herbivorous animals that are purelydependent on the producers or green plants for their food.

Eg. Insects, rabbits, deer, cows are some of the herbivores inthe terrestrial ecosystem and small crustaceans andmoluscus in the aquatic habitat.


17/86

II.CONSUMERS OF SECOND ORDER OR SECONDARYCONSUMERS:

These are carnivores and omnivores. Carnivores areflesh eating animals that are adopted to consumeherbivores as well as plants as food.

Examples of secondary consumers are sparrow,crow, fox, wolves , dogs, cat and snakes etc.


18/86

III.CONSUMERS OF THIRD ORDER OR TERTIARY

CONSUMERS:

These are top carnivores which prey upon othercarnivores, omnivores and herbivores. Lions, Tigers,Hawk, vultures etc. are considered as tertiary or top

consumers.

IV.PARASITES, SCAVENGERS:

The parasitic plants and animals utilize the living tissuesof different plants and animals.

The scavengers utilize dead remain of animals and plantsas their food.


19/86

c. DECOMPOSERS AND TRANFORMERS:

Decomposers and transformers are the living components ofthe ecosystem and they are fungi and bacteria.

Decomposers attack the dead remains of producers and

consumers and degrade the complex organic substances intosimpler compounds. Bacteria generally attack on the animaltissue and fungi on the plant tissue.

Plant and animal material is degraded enzymatically andreleased as basic elements into the environment, where theelements are again available to the producers for reuse.


20/86

FUNCTIONS OF ECOSYSTEMS:

An ecosystem is a discrete structural, functional and life sustainingenvironmental system.

The environmental system consists of biotic and abiotic componentsin a habitat. Biotic components of the ecosystem include theliving organisms, plants , animals and microbes.

Whereas the abiotic components includes inorganic matter and

energy.


21/86

Abiotic components provide the matrix for the synthesis andperpetuation of organic components.

The synthesis and perpetuation processes involve energy exchangeand this energy comes from the sun in the form of light or solarenergy.

Thus, in any ecosystem we have the following functional components.Inorganic constituents ( air, water and mineral salts)Organisms ( plants, animals and microbes)Energy input , which enters from outside (the sun)

These three interact and form an environmental system


22/86

These three interact and form an environmental system.

Inorganic constituents are synthesized into organic structures bythe green plants (primary producers) through photosynthesisand solar energy is utilized in the process.

Green plants become source of energy for herbivores which in-turnbecome energy for the flesh-eating animals carnivores.

All the living organisms die after a certain life span the deadorganic remain provide the food for the saprophytic microbessuch as bacteria and fungi and they are called as decomposers.

The ecosystems operating in different habitat such as deserts,forests , grasslands and seas are interdependent one another.


23/86

The energy and nutrients of one may find their way into another so thatultimately all parts of the earth are interrelated , each comprising apart of the total system that keeps the biosphere functioning.

Thus the principal steps in the operation of ecosystem are follows:

Reception of the radiant energy of the sun

Manufacture of organic materials from inorganic ones by producers


24/86

Consumptions of producers by consumers and further

elaboration of consumed materials and

After the death of living producers and consumers, complexorganic compounds are degraded and finally converted bydecomposers and converts into such forms that are suitable forthe utilization by producers.

It is clear that there is transfer of both energy and nutrients from

producers to consumers and finally to decomposers and

transformers level.

In this transfer there is progressive decrease of energy.


25/86

Kinds of EcosystemsA) Natural Ecosystems: They are capable of

operating and maintaining themselves withoutany major interference by man.

Natural Ecosytem is two types permanent naturalecosystem and temporary natural ecosytem

Temporary Natural Ecosystem e.g rainfed pond

Permanent Natural Ecosystem

1)Terrestrial Ecosystems

Forest, grassland and desert ecosystems


26/86

2) Aquatic EcosystemsFresh water ecosystems

A) Lotic Ecosystem Running Water

Eg. River, SpringB) Lentic Ecosystem : Standing Water

Eg. Pond, Lake, Swamp and

Marine ecosystems eg: ocean, sea etc.


27/86

B) Artificial Ecosystems:Theseare maintained by man. These

are manipulated by man fordifferent purposes.

Eg: artificial lakes and reservoirs,townships and cities.


28/86

C) Incomplete Ecosystems:

Those ecosystems that do not containall the four basic components i.e.abiotic substances, producers,

consumers and decomposers arecalled as Incomplete ecosystems.


29/86

Forest Ecosystem:

Forest are the natural Plant

communities with dominance offlowering plants. Tree, shrubs,flower are present in plenty

In India forest occupy about 18 to20 % of the total land area.


30/86

Types of forest ecosystem

1. Tropical Evergreen Forest:

These forest contain a deep and

dense vegetation of tall tree.

2. Tropical deciduous forest

These forest have broad leaved trees

growing with shrubs, bushes and

creepers in between them.


31/86

Temperate deciduous forest

These occur in the area where welldefined winters alternative with welldefined summer with sufficient

rainfall.

Eg. Maple, elms, oak, peaches etc.


32/86

Coniferous Forest

These forest found in colder regionsThe dominant species are pine,poplar.


33/86

Abiotic component

1. Inorganic component

Minerals, metals, gases like co2,

NO2, SO2 etc.

2. Organic component

Eg. Fats, glucose, amino acid


34/86

Atmospheric component

Climatic component:

1. Temperature

2. Humidity3. Rainfall

4. Wind Velocity

5. Pressure


35/86

.Biotic Component:

Biotic component consist of living

organism represented by producer,consumer and decomposers.


36/86

1.Producers:

Producers are trees of different kind.Besides trees, shrubs & herbs are also

present.

Producers are called Autotrophwhichmade their food by themselves inthe presence of sunlight ,

chlorophyll.


37/86

Consumer / Hetrotrophs:Consumer are represented by

herbivores, carnivores andomnivores which are directly orindirectly dependent on producersfor their nutrition.


38/86

Consumers are further divided into herbivores and carnivores.

Herbivores:

Like ants, flies, beetles, leafhopper feed trees, leaves while larger herbivores areelephant, deer etc.

Carnivores

Small Carnivores like snake, birds, fox feed on herbivores.

Large Carnivores : Lion & Tiger feed on small carnivores and herbivoresConsumersare further divided into herbivores and carnivores.s


39/86

Decomposer

A variety of micro organism likebacteria , fungi , protozoa whichdecompose the dead body of plant

and animal and convert into simplerform.

During decomposition process nutrient, nitrogen & carbon di-oxide gas is

released.


40/86

Pond as an Ecosystem

A pond is a self sufficient and selfregulating system.

It can be divided into four basicunits:

1)Abiotic Substances

2)Producers of a pond

3)Consumers

4)Decomposers

d


41/86

Pond Ecosystem


42/86

I)Abiotic substances:These include water, oxygen, carbon

dioxide, nitrogen, phosphorous,

amino acids, and humic acid.

A part of these nutrients is in

solution and is readily available toorganisms.



43/86

II) Producers of a pond:Are of two types:

1) Rooted or large floating plants generallygrowing in a shallow water.

2) Minute floating algae calledphotoplankton. When in abundance, thephotoplankton give greenish color to the

water. They are important in theproduction of basic food in theecosystem



44/86

III) Consumers:

They cant make their own food. They feeddirectly on living plants and their ownremains. In a pond, there are three kinds

of consumers:

a)Primary Consumers: They are

largely herbivores. They feed directly onplants.

i) Benthos: Benthic population of a pondincludes insects, larvae, fish, moluscus

etc.


ii) Zooplankton: They mainly feed


45/86

ii)Zooplankton: They mainly feedon phytoplankton and includesprotozoans etc

b) Secondary Consumers:

These are carnivores, that feed onprimary consumers or herbivores,In a pond, beetles feed uponzooplankton. Fish consumes small

fish, larvae and zooplankton

c) Tertiary Consumers: They are


46/86

c) Tertiary Consumers: They arethe predators, large fish feed uponsmall fish and thus become the top

consumers.

IV) Decomposers:

When other physical conditions liketemperature are favourable theaquatic bacteria and fungi

decompose the dead organismsand the materials are released forreuse.


47/86

Food Chains

The producers, consumers, and decomposersof 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.

In each transfer some energy is lostTherefore the shorter the food chain thegreater the energy available to thatpopulation.


48/86

Food chains are of two basic types:

1. THE GRAZING FOOD CHAIN:

This type of food chain starts from the green plant

base goes to grazing herbivores and on carnivores

2. THE DETRITUS (ERODED) FOOD CHAIN :

Which goes from non-living organic matter into

microorganism and then to detritus feeding organism and

their predators.

Predator: An organism that lives by preying on other

organisms.


49/86

Characteristics of food chain

In a food chain ,there is repeatedeating in which each group eats thesmaller one and is eaten by

the larger one

In a food chain there is unidirectionalflow of energy from sun to producer

and then series of consumers .


50/86

Usually 80-90% of potential energyis lost as a heat at each transfer.

Usually there are 4-5 trophic levelsin the food chain ,shorter food chain

will provided greater energy.

a food chain is always straight .

Omnivores generally occupy more

than 1 trophic level in a food chain .


51/86

Example of a Food Chain


52/86

Food web is the network of foodchains where different types oforganisms are connected at different

trophic levels ,so that option ofeating and being eaten at eachtrophic level.

F d W b


53/86

Food Webs All the food chains in an area make up the food webof the

area.


54/86

FOOD WEB:

A food web is a complicated system ofrelationships between plants, animals, andenergy.

Understanding their connection is veryimportant in helping to understand anyecosystem.

In an ecosystem one organism does not

depend wholly on another.


55/86

FOOD WEB:

The resources are shared especially at thebeginning of the chain. Food webs are actuallymade up of smaller food chains which areinterconnected.

A food chain, explains what an organism mighteat, and what might eat it in a specific scenario(there are usually hundreds of different possiblefood chains for an organism!). For example, a foodchain could look like this:SUN (energy)-> plant (producer)-

>mouse>snakes>owls

Food web of a hot spring


56/86

2003 John Wiley and Sons Publishers

Food web of a hot spring

Food web


57/86

Food web


58/86

Significance of food web

The food web provides alternatepathways of food availability e.g. ifparticular crop is destroyed due to

some disease ,the herbivores in thatarea do not perish as these cangraze on other types of crop or herbs

.greater the no of these alternatepathways more stable is theecosystem.


59/86

These also help in checking overpopulation of highly fecundivespecies of plants and animals .

Food webs also help in ecosystemdevelopment .


60/86

Ecological Pyramids

An ecological pyramid(also trophicpyramid or energy pyramid) is agraphical representation of trophic

structure and function of anecosystem, staring with producer atbase and successive trophic levels

forming the apex.


61/86

Term Ecological Pyramids coined byCharles Elton

TYPES OF ECOLOGICAL PYRAMID

Pyramid of NumberPyramid of Biomass

Pyramid of Energy


62/86


63/86


64/86


65/86


66/86

Ecological succession

Is defined as an orderly process ofchanges in community structure andfunction with time mediated through

modifications in the physicalenvironment and ultimatelyculminating in a stabilized ecosystem

known as climax


67/86

On basis of different

substrata ecologicalsuccession

Hydrosere ( water ) Mesosere ( adequate moisture)

Xerosere ( dry area with little

mositure)


68/86

Xerosere

Lithosere

Psammosere

Halosere


69/86

Process

Nudation

Invasion

Competition and coaction

Reaction

Stabilization


70/86

Hydrosere

Free floating stage ( pioneer )

Rooted floating stage

reed swamp stage

Sedge meadow stage

Woodland stage

Forest ( climax)


71/86

Xerosere

Lichen ( pioneer)

Mosses

Herbs

Shrubs

Forest ( climax)


72/86

Biogeochemical cycle

Nutrients like carbon ,nitrogen, sulphur,oxygen, hydrogen,phosphorus etc movein circular paths through biotic andabiotic components and are thereforeknown as biogeochemical cycle

A i i th t ti f th th


73/86

. A reservoiris that portion of the earththat acts as a storehouse for the element.

. An exchange poolis the portion of theenvironment from which producers takechemicals, such as the

atmosphere or soil.The biotic communityis the pathway(i.e., food chains) through whichchemicals move.

Some cycles are primarily gaseous cycles(carbon and nitrogen); others aresedimentary cycles, (phosphorus

Energy flow in an


74/86

Energy flow in anecosystem

Energy flow is the key function of anecosystem .

There is unidirectional flow of

energy

During each transfer 80-90%energy is lost in a form of heat in

metabolic reaction e.g. respirationand excretion.

10-20% of energy is available in

next trophic level.


75/86

There is corresponding decrease inbiomass

Energy follows 1st and 2nd law ofthermodynamics


76/86

First law of thermodynamics

Energy can neither be created nor bedestroyed it can be converted fromone form to another form.

Second law of thermodynamics

Every Energy transformation involvesdissipation or degradation of energy

from concentrated to dispersed formdue to metabolic functions ,So thatonly part of energy is stored in the

biomass


77/86

Segments of Environment

The Earth


78/86

1.The hydrosphere is the zone of water thatcovers over three-quarters of the earth.

a. Sunlight drives the water cycle.

b. The ability of water to absorb and releasegreat quantities of heat keeps climate within

livable range.

2. The atmosphere is the gaseous layer nearearth.

a. The atmosphere is concentrated in lowest

10 kilometers; extends thinly out to 1,000b. Major gases are nitrogen, oxygen andcarbon dioxide.

c. Carbon dioxide is necessary forphotosynthesis.


79/86

Atmosphere has 4 layers

Troposphere

Stratosphere

Mesosphere

Thermosphere

Troposphere


80/86

Troposphere

Starts from earth and extend across18 km

Lowest part of atmosphere

Dense atmosphere As altitude increases temperature

decreases

All weather change took place here Clouds are formed here

Tropopause separates troposphere

from stratosphere


81/86

Stratosphere

Starts just above troposphere

It extends upto 50 km

Here atmosphere is dry and dense

Temperature increases due toabsorption of u.v.radiation

Ozone layer is present here

Strato pause separates stratospherefrom mesosphere.


82/86

Mesosphere

Starts just above stratosphere

It extends upto 85km

Temperature again decreases asaltitude increases

Meteorites burns and disintegrateshere

Mesopause separates mesospherefrom thermosphere


83/86

Stratosphere &stratopause

Mesosphere & mesopause

Are middle layer of the atmosphere


84/86

Thermosphere

Starts just above mesosphere

It extends upto 600 km high

Temp increases with altitude due tosun energy.

Thermosphere is subdivided into 2layers ionosphere and exosphere


85/86

Oxygen is necessary for cellular respiration, and is protective ozone(O3) in upper atmosphere.

3. The lithosphereis a rocky substratum that extends about 100kilometers deep.

a. Weathering of rocks supplies minerals to plants and eventually

forms soil.

b. Soil contains decayed organic material (humus) that recyclesnutrients to plants.

4. The biosphereis the thin layer where life is possible betweenthe outer atmosphere and the lithosphere


86/86

Thank You

ecosystem enviromental studies

Documents