ECOSYSTEM
Note: This material is designed and developed by Mr Ramesh, an eminent faculty member from Hyderabad. I express my gratitude for his contributions.
N. Kalyana Chakravarthy
The term ecosystem was
coined by Roy Clapham-1930 and was used by Arthur.G.Tansley-1935 (British
ecologists).
·
It was derived from
Greek word “oikos- house”. Ecology- house -keeping.
·
DEFINATION: It is a
dynamic complex- the study of earth’s house- holds including the plants, the
animals, the microbes and the people that live together as intermediate
components. (or)
·
The totality of
patterns of relations between organisms and environment.
·
ECOLOGY: The scientific
study of the relations that living organisms have with respect to each other
and their natural environment.
OIKOS- House
LOGOS-study: ecology-oekologie
·
In other words ecology
simply means the study of house or the place where we are living.
·
Ecology is the
interdisciplinary field that includes biology and the earth sciences.
·
Ancient Greek
philosophers such as Hippocrates and Aristotle laid the foundations of ecology.
·
The word ecology was
coined by German scientists ‘Ernst Haeckel’ in 1866.
·
Ecology is not related
to environment or environmental history, but is closely related to the
evolutionary biology, genetics and ethology.
·
It is a scientific and
objective study of animal behavior.
·
Claments in 1969
defined ecology as a science of communities.
·
The focus area of
ecological studies is to understand the ecological functions and how they
affect the biodiversity.
·
The scope of ecology
has widened and now there are many practical applications of ecology in
-conservation biology
-wetland management
-natural resource
management ( agro ecology-agriculture, forestry, agro forestry, fisheries)
-city planning (urban
ecology)
-community health
-applied science
-human social
interaction
·
Ecosystem maintains the
biophysical feedback mechanism that modulate metabolic rates and evolutionary
dynamics between biotic and abiotic components of planet.
·
Ecosystem sustain life
supporting functions and produce natural capital through the regulation of
1. Continental
climate
2. Global
biochemical cycles
3. Water
filtration
4. Soils
5. Food
6. Fibers
7. Medicines
and many other natural features of scientific, historical, economic and
intrinsic value.
Basic
Terminology of Ecology:
1 .BIOSPHERE: The earth ecosystem
functioning together on a global scale is called biosphere. It is an amalgamation
of all the areas of ecosystem of the earth where life exists.
Generally it is said that the life
exists till the elevations of troposphere –average 14-18km above mean sea
level, till the abyssal plain i.e to the deepest of the ocean bottom (11.02)
2. BIOME: It includes the total
assemblage of the plant and the animal life interacting with the life layer (
biosphere). The green plants dominate the biomes because of the enormous
biomass and the biomass are classified by the characteristic life form of the
green plants with in it and accordingly 5 principal biomes have been identified
on the earth surface.
Ex: Forest biome: with ample water and
temperature
Savannah biome: transmission between forest
and grassland
Grassland biome: moderate shortage of soil
water and adequate heat
Desert biome: extreme adequate heat
Tundra biome: insufficient heat and water.
3. BIOTIC COMMUNITIES: These are the
local associations of plants and animals that are interdependent and often
found together i.e they represent a group of animals and plants or the
individuals of different species inhabiting a geographical area.
4.POPULATION: A Group of animals
belonging to the same species is called as the population i.e the individuals
of the same species inhabiting in a geographical area together are called as
population.
5. SPECIES: It is a group of organisms
i.e the plants and the animals with similar genetic characteristics and they
interbreed among themselves and produce fertile off-springs.
Every species is reproductively isolated
from such other species and capable of interbreeding.
6.ECOTONE: It is a transitional zone
between two different ecosystem, this zone consists of the living organisms
from both adjoining biotic communities of its own.
The best natural ecotone can be the
brackish water ecotone i.e the creek or the estuary, where we can find both the
marine and also the fresh water living things.
Eco= house; tone=tension (Greek). These
are places where ecologies are in tension ,Ecotone may be local or regional.
8.ECOLOGICAL NICHE: The status occupied
by an organisms in an ecosystem is called Niche. Ex: human beings are the consumers, plants
are the producers.
DEFINATION: Niche is the set of biotic
and abiotic conditions in which a species is able to persist and maintain stable
population sizes- said
by Evelyn Hutchinson.
8.ECOLOGICAL SUCCESSION: The biotic
communities succeed one another on the way to stable end point referred to an
ecological succession.
9. SERE: Serial community, the series of
communities that follow one another on the way to stable end stage.
10.PRIMARY SUCCESSION: It is the second
community which has taken over the virgin community.
11.PIONEER STAGE: It is the first stage
of succession.
12. AUTOGENIC SUCCESSION: The series of
communities, succeeding due to the action of plant and animal themselves.
13. CLIMAX: The last stable community at
end point is called the climax community, but due the human intervention these
communities are getting changed. Ex: teak overtaken by bamboo.
Henry Cowles-1899 wrote climax
Frederic Clements-1900 used the term to
describe.
ECOSYSTEM:
Ecosystem are habitats within the biomes
that form an integrated whole and a dynamically responsive system having both
physical and biological complexes (George Perkin Marsh -1864)
The totality of patterns of relations between organisms and environment.
Ecosystem is of 3 types
a) Terrestrial
ecosystem
b) Aquatic
ecosystem
c) Artificial
ecosystem( techno ecosystem)
a)TERRESTRIAL
ECOSYSTEM: There are 5 principal types of
terrestrial ecosystem present, they are
1. FOREST
BIOME: Includes all regions of forest , it is an assemblage of trees growing
close together forming an layer of foliage that largely shades the ground.
Frontier forests are the ones which are not
disturbed by the human activity, the forest biome often show stratification and
they span a wide range of climates and latitudes from the equatorial climate to
the boreal forests and 6 types of forests biome are identified.
a) equatorial forests
b) tropical rain forest
c) monsoonal rain forests
d) broad lea evergreen or temperate rainfall or
laurel forests
e) mid latitude deciduous or summer green forests
f) needle leaf forests
2. SAVANNAH
BIOME: It consists of combination of trees and grasslands in various
proportions, it appearance is like a park, single tree surrounded by the
grasses and shrubs.
The crowns of the trees are flattened and the trunks
with thick and rough bark. This is to resists the summer in fire.
Species: Acacia, Grotesque, baobab ( the axe
beaker), elephant grass etc
In south Americas Savannah biome i.e campo cerrado,
the trees are largely broad leaved and evergreen.
3. GRASSLAND
BIOME: It consists of largely and
entirely of herbs i.e grasses and grass like plants, the trees are almost
totally absent.
Ex: North .America – Prairies
South
America- Pampas
Europe- Steppes
Africa-Veldts
Australia- Downs
New
Zealand- Canterbury plains
Hungary-Puztas
Prairies are the tall grasses
Steppes are the short grasses
In America short grasses are called buffalo grasses.
4. DESERT
BIOME: Large surface proportions are bare ground without any vegetation and it
is exposed directly to the natural forces, although treeless but contains “scattered
woody vegetation”. Desert biome is of 3 types.
a) Thorn tree semi-desert: it has long and hot dry
season. Ex: Caatinga in NE Brazil, Dorn veldt in South Africa
b) Semi desert: it has xerophytic vegetation with
poorly developed herbaceous layer. Ex: sage brush of southern rockies and
colarado
c) Dry desert: with no important degree of ground
cover. Ex: in Australia the desert alternatives with porcupine grass
In Mojave – sonorant desert plants are often tree
like
ex: saguaro cactus, prickly pear, cactus, ocotillo,
cuosote brush, smoke trees
In Sahara desert. EX: Stipa and tamarix these all
the trees which maintain dormant state to survive.
5. Tundra
Biome: It also consists of grasses along with abundance of flowering herbs,
dwarf shrubs, mosses and lichens. Its ground cover is spotty.
During summers the marshy conditions prevail due to
permafrost conditions. The small plants in these areas are annuals, many
species flower brightly in summer.
The number of animal species is very small.
EX: Caribou, Reindeer, Artic foxes and polar-bears
are predators
Mosquitoes and flies are abundant in July and it is
most uncomfortable for humans and other mammals.
The foggy tundra offers an ideal summer environment for
many migratory birds.
Forests- ample soil water and heat
Savannah-transitional between forests and grasslands
Grassland-moderate shortage of soil water and
adequate heat
Desert- extreme shortage of and water adequate heat
Tundra- insufficient heat
Tropical zone: palms and bananas
Sub- tropical zone– laurels and myrtles
Warm temperature- evergreen forests
Cold temperature- deciduous forests
Sub -arctic –zone of coniferous
Polar-
zone of alpine shrubs mosses and lichens.
B)
AQUATIC BIOME: There
are many kinds of aquatic ecosystem that differs with regard to all abiotic
factors.
The aquatic ecosystem range from an open
ocean to small temporary ponds, having fluctuation conditions of salinity,
depth and temperature.
The adaption of aquatic ecosystem varies
in diversity and degree. Some of them are exclusively aquatic and some are
amphibious in nature.
Marine ecosystems are the largest
aquatic ecosystem and they include
A) Oceans
B) Salt marsh
C) Inter tidal ecology
D) Estuaries
E) Lagoons
F) Mangroves
G) Coral reefs
H) Deep sea
I) Sea floor
The marine ecosystem cover 2/3rd
of surface of earth, they are very important for overall health of both marine
and terrestrial environment. They are most productive regions providing food
and shelter.
The coral reefs shelter the highest
levels of biodiversity in the world. Hence they are called as the rainforests
of the tropical oceans. The marine ecosystem oceans contains 97% of the planet
water and they generate 32% of the worlds net primarily production.
The marine ecosystem are distinguished
by the presence of dissolved compounds specially salts.
FRESH WATER
ECOSYSTEM: It is characterized by its low concentration of salts and mineral
ions, and they constitute -0.09% of the planet water and they generate 3% of
the world’s net primary production. They are of 3 types
1. The Lentic
ecosystem: it literally means slow moving water but includes the lake and pond
ecosystem., both are characterized by stagnant fresh water bodies and occur
practically in every biome.
They also vary
in their sizes from less than a hectare to thousands of hectares like
Victoria(Africa), Superior(USA), Caspian sea(Central Asia)- these are lakes
having rich accumulations of organic compounds called Eutrophic lakes; poor in
nutrients called oligotrophic lakes.
2.The lotic
ecosystem: it literally means the rapidly moving water and includes the streams
and rivers, both of the differ from each other in volumes of water they carry,
the speed of flow, oxygen content, temperature, ph value and other several physical and chemical
conditions.
Even the
phytoplankton and the zooplankton population varies.
3. Wetland
ecosystem: It is a land area that is saturated with water either permanently or
seasonally. The water found in wet land can be saltwater, freshwater, and
brackish.
The main wetland
type includes ‘swamps’, fogs, marshes, fens. Wetland plays a number of roles in
the environment, principally
-water
purification, flood control, shoreline stability.
The
largest wetland in the world include the
·
Amazon river basin,
·
West Siberian plain
·
Pantanal (Brazil)
FUNCTIONS
OF THE AQUATIC
ECOSYSTEM:
·
They recycle the
nutrient
·
They purify the water
·
They attenuate the
floods
·
They recharge the
ground water
·
They provide habitat
for wildlife
·
They provide human
recreation
The
abiotic characteristics present are temperature, salinity and the flow or
discharge and they are the auto and heterotrophs.
·
The salt tolerant
organisms are called as Euryhalines. The salt intolerant organisms are called
as Stenohaline.
MICRO ECOSYSTEM:
They are also called as experimental ecosystems. These are the artificial,
simplified ecosystems that are used to stimulate and predict the behavior of
natural ecosystems under controlled conditions.
c) ARTIFICIAL AND MANMADE ECOSYSTEM: This
include villages, plantations, parks, fishery tanks, aquarium and the
agriculture lands.
Agriculture ecosystems
are the most important ones.
INTERACTIONS
The interactions
among different species of animals in an ecosystem are different. The major
components of interactions that prevail in ecosystem are
1. PREDATION:
This is a direct food relation between two species of animals; one is predator
and capture which feeds on the prey.
2. SCAVENGING:
The wolves, Jackals, Hyenas and vultures feed on other organisms which have
died naturally or some left overs.
3. PARASITISM:
This is a harmful association between two species, which results in the damage
or harm to one and benefit to other species
4. SYMBIOSIS:
This is a beneficial association where two species benefit from each another
5. COMMENSALISM:
This is a relationship which involves struggle among the organisms of same
species, where one is benefitted without harming the other.
6. COMPETITION:
This is a relationship which involves struggle among the organisms of same
species or among the organisms of different species.
7.PROTECTIVE
INDEPENDENCE: In a biotic community trees and other plants hide and protect
animals by providing shelter from enemies and hostile weather, many of them
camouflage themselves to suit the environment.
8. MIMICRY: It
is the superficial resemblance of one organism to another to escape itself from
the adversities as being harmful which is not actually the case.
STAGES: All the
ecosystems present in the world can be put under 3 stages or states in terms of
changes with time.
1.GROWTH
ECOSYSTEM: This is the ecosystem which is under the process of growing where
the successions are still in process.
It is represented as
And it is
graphically represented as positive transient stage
2.BALANCED
ECOSYSTEM: This is the ecosystem which has reached the balanced stage i.e it
has attained the climax stage
3.AGENING
ECOSYSTEM: This is the ecosystem which has achieved its climax stage and
residing back or dieing off, may be due
the un-favourable circumstances of climate.
COMPONENTS:
Ecosystem
consists of two components namely the abiotic and biotic components.
1.ABIOTIC COMPONENTS: They are non-
living components present in the ecosystem, it is of 3 types
a)Inorganic
components: They includes the substances like C, N, WATER, etc
b)Organic
components: They include like protein, lipids, carbohydrates etc, they are
essential for the origin of life. Organic components acts as a link between
abiotic and biotic components.
c)Climatic
components: They include the physical factors of climate like the temperature,
rainfall, pressure conditions etc
These are the
physical factors which are responsible for the survival for the living.
2. BIOTIC COMPONENTS: They are the
living components present in the ecosystem and are put under 2 groups.
a)Autotrophic
components: These are self-nourishing components present i.e the plants, they
are the producers. They fix the light energy and manufacturing the food
materials from simple to inorganic substances with the help of chlorophyll
b)Heterotrophic
components: Nourishing on others i.e the consumers, they utilize and decompose
the complex materials synthesized by the autotrophs.
They are divided
into 2 groups.
A)
MACROCONSUMERS: They
depend directly or indirectly on producers, they mostly include the animals,
which exhibit the zoo-trophic nutrition.
Based
on the dietary habits they are of 3 types
(I)Primary
Consumers: They are the herbivores animals which directly depends on the
autotrophs. Ex: grasshopper, rabbit, cattle, elephant etc
(ii)Secondary
Consumers: They are carnivores animals and eat the herbivores, since their food
consists of primary consumers, they are called as secondary consumers. Ex:
frogs, birds
(iii) Tertiary
consumers: They are the consumers of third order, these are top class
carnivores, the members of which are not killed and eaten by others.
They depend
directly on both primary and secondary consumers. Ex: tigers, lions, sharks,
whales etc
B)MICROCONSUMERS:
They include the decomposers i.e the microbes like bacteria, fungi.
They are also
called as the detritivores because they depend on dead biotic components.
These microorganisms
breakdown the complex organic compounds present in the dead plants and animals
into simpler substances. They play a very important role by releasing and
recycling back the materials into the soil and atmosphere.
Decomposers comprises a very large and diverse group of
organisms which act at different level.
FUNCTIONS:
There are two
great principles or laws of general ecology, which are applicable in all the
ecosystems and are called as the functional aspects of ecosystem. They are
except under extreme conditions, different ecosystems are often able to
maintain the same level of productivity under different condition of
temperature or other factors.
1.One way of
energy flowThe energy flow can be better understood by the productivities of
the ecosystems which are of two types
Sunàatmàtreesàleavesàherbivoresàcarnivoresàdecomposers.
50lakhsà10lakhsà5lakhsà2000à200à40
1.Primary Productivity: The productivity of autotrophs i.e the producers is called as the primary production.
It includes the gross
primary productivity of the ecosystem in the total amount of the organic
substances prepared by the autotrophs minus the energy utilized by them during
the metabolism and catabolism is known as NPP.
NPP=GPP-E
2. Secondary
productivity: The productivity of heterotrophs i.e the consumers is called as
the secondary productivity.
Net secondary
productivity includes the gross secondary productivity i.e the total amount of
organic substances utilized by the heterotrophs as food minus the energy
utilized and the non-digested food i.e excreta
NSP=GSP-E-NDF
The total food
utilized minus the energy spent and excreted is the actual net secondary
productivity.
2.Circulation of
materials: This is again driven by the flow of energy, the energy which is not
utilized will be driving the hydrological cycle and powers the weather system,
it is called as the “ energy lost in the transformation”.
As it is evident
from the above diagram that the energy flow is unidirectional, this flows and
moves along with the food chain from one tropic level to another.
The available
energy at a given tropic level is always lesser than that which was available
in the previous tropic levels. Hence it goes on decreasing from the producer to decomposers.
The circulation
of the materials in an ecosystem is a continuous process, it involves the
cyclic flow of materials i.e the organic and inorganic components between
living and non living environment.
The kind of exchange
of nutrient materials between the living and non- living world is called as the
cycling of matter or” biogeochemical cycles”. Which are mostly helped by the
decomposers.
That’s how the
different components of ecosystem are interdependent on each other.
TROPHIC LEVEL:
The word derived from the GREEK word
TROPH=FOOD OR FEEDING;
LEVEL=STAGE
This is
nutritional status occupied by the organisms in a food chain.
The ecosystem
energy flow biomass and the number of organisms are represented by the pyramids
with different trophic levels. The actual triangle is upright, but the pyramid
for biomass is becoming reversed in nature.
BIO-GEO CHEMICAL CYCLES
The land of
exchange of materials between the living and non -living worlds are called as
boo geo chemical cycles or nutrient cycles. They are classified into 2 types
1.
Gaseous
2.
Sedimentary
For the gaseous
cycles the reservoir of materials in the atmosphere or the water. There are
four major elements in the living organisms which are predominantly gaseous are
“carbon”,”Hydrogen”,”Nitrogen”&”oxygen”.
THE CARBON
CYCLE:
This cycle is
considered as the fars of life ,the carbon is present in all organic matters
from fossil fuels to the complex molecules like DNA ribo nucleic acids.
There are 5
sources of carbon in the world.
I.
As the organic
molecules of “ biosphere”
II.
As the gaseous
molecules carbon dioxide of “atmosphere”
III.
As the organic matter
in the soil
IV.
In the “lithosphere” as
the fossil fuels and in the form of sedimentary deposits as limestone, chalk
etc
V.
In the “hydrosphere”
that is in the oceans as dissolved carbon dioxide and as calcium carbonate
shells in the organisms.
·
The carbon moves from
atmosphere to plants- photosynthesis, i.e CO2 is pulled from air to make food.
·
The carbon moves from
plants to animals – animal consumption, i.e through the food chain
·
A carbon moves from
plants and animals to ground- decomposition, i.e after the death and decays as
fossil fuels.
·
The carbon moves from
living things to atmosphere, i.e through respiration
·
The carbon moves from
fossil fuels to atmosphere, i.e through combustion
·
The carbon moves from
atmosphere to oceans, i.e by sinking and depositions.
Since
the industrial revolution the atmospheric CO2 levels have increased by over 30%
i.e from 275 ppm in the early 1700 to 365 ppm in 2010, and it is estimated that
by 2100 it could reach between 450 to 600 ppm.
This
is because of the human interactions in the form of combustion of fossil fuels
and by modification of ecosystems. The fossil fuels account for 65% of CO2 and
deforestation accounts for 35% of additional CO2 formed in the atmosphere.
THE
OXYGEN CYCLE:
All
the living things need oxygen for generating of energy in cells. The plants
mark the beginning of O2 CYCLE by the process of photosynthesis.i.e the plants
breathe in CO2 and breathe out O2.
Animals
form the other half of the O2 cycle, during their respiration. During nights
plants consume and in day they release it.
The
N2 is the essential constituents of the proteins and the nucleic acids, which
forms the structural and the functional components of living organisms
The
N2 of the atmosphere is not available for the organisms because N2 molecules is
relatively inert, to be useful for plants and animals and it should first be
converted into more useful forms such as the NH4, NO3 or organic N2 i.e urea.
There
are main processes which cycle N2
through the biosphere, atmosphere and geosphere are
I.
NITROGEN
FIXATION:(ammonification)
This
is the process where N2 is converted into NH4 ion and it is done by process of converting free
nitrogen of atmosphere into compounds of nitrogen and done by 3 process.
(a) Atmospheric
fixation by lightening
(b) Biological
fixation by symbiotic relationship of some plants and animals with microbes (
rhizobium, anabaena, azollae, azotobactes)
(c) Industrial
fixation , where nitrogen and hydrogen air made to react with each other at
high temperature and pressure
N2+3H2
----à2NH3at 600c and further processed
to form urea and ammonium nitrate
II.
NITROGEN MINERALISATION:
The ammonium
form is again converted into in organic nitrogen by the death and decay of the
living things and the process is known as nitrogen mineralization.
Sometimes
ammonium and nitrate are also formed during decay
III.
NITRIFICATION:
The
ammonia formed is converted into nitrates and the nitrites, the process of
conversion is called the nitrification.
The
ammonia is acted upon by nitrifying bacteria, nitrosomanas,nitrobacteria and is
changed to nitrates.
IV.
DE-NITRIFICATION:
The
nitrates and nitrites are converted into nitric
and the nitrous oxides, from where the free nitrogen is released back
into atmosphere from the soil by the denitrifying bacteria like the pseudomonas
and the Bacillus denitricans present in the soil and water logged condition.
This
process of conversion of nitrate etc into nitrogen gas is called
denitrification.
V.
The ammonium form of nitrogen is
quickly incorporated into protein and
the other organic compounds.
The
following steps are involved in the nitrogen cycle
·
Atmospheric nitrogen into soil by
bacteria or the lightening- ammonification
·
The plants absorb the nitrates from the
soil and convert them into proteins-assimilation
·
The animals consume plants and plant
proteins are used for making animal proteins
·
Proteins of plants and animals are
decomposed into ammonia by putrefying bacteria and fungi- ammonification
·
The ammonia is converted into nitrites
to nitrates by nitrifying bacteria or nitro factor- nitrification
·
The nitrates of the soil are converted
back into free nitrogen gas by denitrifying bacteria- denitrification
Approximately
140 million metric tones of nitrogen is added to the ecosystems every year. The
human activities are altering the nitrogen cycle by
(a) Adding
nitrogen fertilizers
(b) Combustion
of fossil fuels
(c) By
the forest fires
(d) By
live- stock and ranching water
(e) By
disposal of sewage waste
For
the sedimentary cycles the reservoir of the materials is the lithosphere and
the involving minerals are phosphorous, Sulphur and the calcium etc
PHOSPHOROUS
CYCLE:
The
phosphorous is an essential nutrient for both the plants and animals because it
is a part of DNA, RNA, ATP, ADP and is
also useful for strengthening of the bones and teeth.
It is
the solvent of all the material cycles, the plants absorb it from the water and
the soil, from them plants, they are available to the animals. When animals
die, the decomposers release P into the soil again or sometimes into the
oceans.
It is
not soluble in water and hence when it enter the lakes and the oceans it turns
into sedimentary rocks, to be released millions of years later.
SULPHUR
CYCLE:
It is
a secondary element with calcium and magnesium, it is a component of couple of
vitamins and it occurs in two amino acids like cysteine and methionine.
It is
also called as important component of co-enzyme-A for cellular respiration. The
chemoautrophic bacteria convert the elemental sulphur into sulphates.
2S+H2O+3O2-----à2H2SO4
This
sulphates are transformed into a reduced state, the sulphidei.e H2S by sulphur
bacteria.
During the decomposition of animal protein, which is a source of
sulphur, the bacteria removes sulphide group
During
the anaerobic respiration H2s is oxidized to form H2 and S for release of
energy. The volcanic eruptions and the hot springs also release S into
atmosphere.
FOOD CHAIN:
The
transfer of food energy from the source in plants through of organisms with
repeated states of eating and being eaten is food chain. In the food chain
always the green plants will occupy the first trophic level.
All
organisms living or are potential foods
for some other organisms and thus, there is essentially no waste in the
functioning of a natural ecosystem.
Depending
on its nutritional status, each organisms in an ecosystem is assigned a feeding
on trophic level.
It is
a dynamic part of ecosystem which facilitates the continuous flow of energy.
The food chain are of two types.
1. GRAZING
FOOD CHAIN:
It
states with the autotrophs i.e the grasses or the green plants, from them it
goes through the herbivores and then finally culminates in carnivores.
2. DETRITUS
FOOD CHAIN:
It
starts with dead organic matter which the detrivores and the decomposers
consume.
The
partially decomposed dead organic matter and even the decomposers are consumed
by the detritivores and their predators.
The
leaf fragments are eaten by saprotrophs( theyare the organisms which feed on
dead organic matter)
Ex:
leaf litterà
algaeàcrabsàsmall
carnivores fishàsmall
carnivores fish –Mangrooves ecosystem
Dead
organic matteràfungiàbacteria—Forest
ecosystem.
The
food chain is explained by “Y” shaped energy model flow by considering both the
types of food chains.
Grasslandsàplants:
50% herbivores-predators, 50% detritus-predators
Mature
forestsàplants:
10% herbivores- predators,90% detritus-predators.
Ecosystem
have become particularly important politically since the CBD convention on
biological diversity, which was ratified by 192 countries for the protection of
ecosystems, natural habitats and maintenance of variable populations of species
in natural surroundings.
BIODIVERSITY
It refers to the incredible variety of
life found on our planet. Biodiversity is the shortened term for biological
diversity.
It is an umbrella term used to describe
the number of varieties and variability of living organisms in a given assemblage.
Biodiversity, therefore embraces the
whole of life on the earth.
It is described as the totality of
genes, species and ecosystems corresponding to 3 fundamentals and
hierarchically related levels of biological organization.
The concept of biodiversity was
introduced by W.G.Rosen in 1985 and was popularized by Manus and Norse.
The life on earth is so diverse that we
really have no idea that how many species are there.
The estimates fall in between
15-30million species of plants and animals and only 1.5-1.8 million species
have been identified majority of them are un-indentified. Out of 34known animal
phyla, only one phylum lives exclusively on land, 14 of them in oceans and rest
19 are amphibians in nature.
Approximately 7,50,000 insects, 41,000 vertebrates,
2,50,000 plants are described.
Biodiversity is the focal point to our
existence because
We derive the food which was once wild
and we rely on the wild to improve the domesticated ones.
We derive the medicines from plants and
animals to develop new drugs for treatment of various diseases. The human
civilization continued for several thousands of years, was on the herbal
medicines and even now we are extracting the required chemical formulae from
the plant species.
The biodiversity provides a vast gene
pool and the genetic resources for increasing the vigor by hybridization.
Change in the gene pool may cause the depletion of the species themselves by
the pests and insect attack. Ex: rice
The natural ecosystems in the form of
national parks and sanctuaries are providing recreation for the distressed
souls.
By the study the biodiversity the
conversation of the endangered species, the links in the food webs can be done.
Which may make available of more bigger gene pool and more chances of human
survival.
TYPES
OF BIODIVERSITY:
There are 4 types of bio-diversities
identified.
1.BIOLOGICAL DIVERSITY: It means the
full range of variety and variability with in and among the living organisms
and the ecological complexes in which they occur. (or) it is a variety of life and its processes in
the ecosystems.
2.GENETIC DIVERSITY:
It refers to the variation of genes
within the species.
Ex: 10,000’s of rice varieties present
in India.
3.SPECIES DIVERSITY:
It is a variety and abundance of
different types of organisms which inhabit a geographical area. It is the
species richness of an area and it is also called as taxonomic diversity.
Ex: An island with two species of birds
and one species of lizard has great taxonomic diversity than an island having 3
species of birds present.
4.
ECOSYSTEM DIVERSITY:
It includes the variety of habitats that
occur in a region. It is harder to measure.
Ex: the grass land ecosystem, deserts,
savannahs etc.
Newly even the Agro biodiversity and microbial
diversity are added.
Since 2000, 53 new species of primates
have been described.
Ex: Brazilian monkey, Mura’s saddle back
tarrarin etc.
BIODIVERSITY
VALUE:
The biodiversity has got 3 values
namely.
ECOLOGICAL VALUE:
All living organisms are supported by
the interactions among organisms and ecosystem. The loss of biodiversity makes
ecosystem less stable and more vulnerable and also weakens its natural cycles.
ECONOMIC VALUE:
Everything we buy and sell originates
from the natural world. Nature provides the raw materials which we need for
survival.
At least 1650 known tropical forest
plants have the potential to be grown as the vegetable crops. Nature is a
source for many medicines etc.
CULTURAL VALUE:
Most people feel connected to nature,
often the reasons are hard to explain. Some feel strong spiritual bond and
others are inspired by its beauty.
BIODIVERSITY
DIVISIONS:
The are 2 important divisions of
biodiversity namely
ALPHA-DIVERSITY: ( or within the habitat
diversity)
This refers to a group of organisms
interacting and also competing for the same resources and sharing the same
environment.
BETA DIVERSITY: ( or between habitat
diversity)
This refers to a group of organisms
living in different habitats, but interacting and competing for the same
resources by encroaching into each other or different habitats.
PATTERNS:
The patterns of diversities change in
relation to space and time.
IN SPACE:
We know that species diversity declines with
increasing distance from the equator and the rich biodiversity of tropics is
due to
the tropics remained relatively
undisturbed ( no frequent glaciations ), so it had a long evolutionary time for
species diversification.
More solar energy means more
productivity which indirectly contributes to more diversity.
More the variable the habitat, greater
is the species diversity in that habitat.
IN TIME
SEASONAL PATTERN: Diversity of species
will vary during different seasons of the year. Since, the birds and animals have the different breeding
seasons, migratory behavior etc.
SUCCESSIONAL PATTERN: After the
disturbances of ( fire and agriculture ), the plants and animals begin to
reoccupy the habitat.
In this process other species out
compete the original inhabitants.
EVOLUTIONARY PATTERN: Around 225 mya and
phyla stopped increasing. 66 mya, the new classes stopped increasing whereas
the new orders, families, genera and species are going on increasing.
LOSS
OF BIODIVERSITY:
The loss of biodiversity is most
fundamental, it is natural and also irreversible.
All the species have a finite span of
existence, so species extinction is a natural process which occurs without
human intervention.
It is beyond the doubt that extinctions
caused by human are occurring at a faster rate and far exceeds the natural rate
and far exceeds the natural rate.
The global convention on biological
diversity of 1992 “ The Earth Summit”.
It has devised 10 policy fields causes
for the loss of biodiversity and one of that is mankind, is destroying the
natural heritage at an incredible speed.
The biodiversity is facing threats.
There are 4 major causes for the loss of biodiversity.
HABITAT LOSS AND FRAGMENTATION:
One of the most cause for the extinction
of plants and animals is habitat loss and fragmentation, it is due to the human
activities like expansions of the habitations, construction of transportation
arteries in the forests, diverting the channels of rivers etc.
Ex: the rainforests are once covered
more than 14% of the land surface now it is decreased to 6%
So when large habitats are broken up
into the smaller fragments, the birds and the animals requiring large
territories are badly effected leading to the population decline.
Ex: Great Indian Bustard in MP, Gujarat
& Rajasthan; loin failed macaque in Western ghats.
OVER-EXPLOITATION:
Humans have always depended on nature
for food and shelter, but need turns to greed it leads to over exploitation of
natural resources
Ex: several species got extinction in
the past 500 years due to over exploitation like the pigeons, sea-cows etc.
Shrinking the biodiversity leads to more
vulnerability to diseases and lesser adaptability to climatic change.
INTRODUCTION TO NEW SPECIES:
Among the major threats faced by the
native plant and animal species is the one posed by the invasive alien species,
its only the second to the habitat loss.
Ex: Alien aquatic weeds like water
hyacinth, lantana and carrot grass
Illegally introduced catfishes and big
head craps adversely affected the native weeds and fishes.
Accidental entry of silver crap into
Govind sagar Dam, over shadowed the native catla and mahseer fish.
In 1859, a farmer in S. Australia
imported a dozen pairs of wild European rabbits, which by 1995 reached every
corner of the country.
CO-EXTINCTIONS:
When species become extinct, the plant
and animal species associated with it also become extinct.
Ex: cutting of huge trees causes the
mini diversity lost like the birds, the insects, the creepers and the shrubs -
under its shade are all lost.
Apart from the above
The climate change is also significant
threat to biodiversity, because it will alter the growth, the reproduction, and
the host –pathogen relationships in both the plants and the animals.
The raising sea levels are already
submerging some of the islands leading to rapid loss of biodiversity.
Unsustainable use of natural resources,
climate change, inappropriate fire regimes, changes to aquatic environment and
water flows.
HOTSPOTS:
The regions with a significant reservoir
of biodiversity, that is under threat from humans.
They are biologically rich areas with
high diversity and large percentage of endemic species.
The concept of Hotspots was forwarded by
British ecologists “Norman Myers” in 1988.The area to be qualified as a
hotspot:
a)It should support 1500endemic plant
species i.e 0.5% of the global total
b)It must have loot> 70% of its
original habitat
Accordingly there are 34 hotspots
scattered, which are representing around 1.4% of the land area, 44% of the
plant species, 35% of all the terrestrial vertebrates.
4 of the hotspots are present in North
and Central America, 4 in Europe and C. Asia, 5 in S. America, 8 in Africa, 13
in Asia pacific ( 2 in India: Indo-Burma and Western ghats-Srilanka)
The world wild life found as devised a
conservation strategy to save the biodiversity hotspots
Global 200 is the list of eco regions
identified by world wildlife fund as the priorities of conservation, and a
total of 238 “G200” regions have been identified.
142 (60%) are terrestrial.
53 (22%) are fresh water.
43 (18%) are marine habitat types.
CONSERVATION:
There are many reasons for biodiversity
conservation which are grouped into 3 categories
NARROWLY UTILITARIAN REASONS:
The narrowly utilitarian arguments for
bio can are from the selfish point of view, humans should be concerned about
saving biodiversity because of the benefits it provides us like biological
resources and ecosystem services, the nature also provides the social and the
spiritual benefits as well.
Biological resources; fall into several
categories like food, medicines, fiber, wood products and more.
Ex: over 700 species of plants are used
for food, although we heavily rely on only 12 major crops.
Ex: opiate pain relievers are from
poppies
-aspirinàwillows
Quinineàchinchona
Rosy periwinkleàvinca
rosea
Pacific yawàtexa
bravifolia
Both provide substances used for
inhabiting cell growth of cancerous cells.
Ex: shark skin provides the model for
hydrodynamic swimming suites.
Glues used by sand castle worm, was the
inspiration for the glue that mends the fractured bones. Spider silk to design
a strong, lightweight fibers.
Ecosystem services: these are the
processes provided by nature that support human life. The activities included
are the decomposition of waste pollination, water purification, moderation of
the floods and renewal of soil fertility,That the humans derive a countless economic
benefits from nature, such as foods and products of medicinal importance.
Ex: 25% of the drugs of the world are
derived from plants. 25000 species of plants contribute to traditional
medicines.
Bio prospecting: exploring the
molecular, genetic and species level products of economic importance from the
living organisms called as bio prospecting.
The nations endowed with rich bio
diversity can expect to reap enormous benefits.
BROADLY UTILITARIAN REASONS:
The broadly utilitarian argument says
that the biodiversity plays major role for all.
Ex: amazon produce 20% of the total
oxygen into earth’s atmosphere.
THE ETHICAL ARGUMENT:
It is that because we share this planet along
with millions of plants, animals and microbes etc. we owe and have moral duty to
care for their wellbeing.
It is the philosophically or spiritually
caused intrinsic values. Many biologists agree that we are in the midst of a
mass extinction, the last great mass extinction was 65 million years. ( when the dinosaurs went extinct at the end
of the cretaceous period)
ICUN : The international union for the
conservation of nature estimates that
22% of the known mammals
32% of the amphibians
14% of the birds and
32% of the gymnosperms are threatened
with extinction.
The species that were abundant with in
the last 200 years have gone extinct.
CONCLUSION: Pass our biological legacy
in perfect order to our future generations.
The biodiversity conservation is
accomplished in a number of ways, but are put under two broad headings
EX SITU METHODS:
Which focus on the species conservation
in botanic gardens, zoos, gene banks and captive breeding programs.
It involves the conservation of the
living organisms not in the site; that not in their natural habitat.
ZOOS: These contribute to the conservation
of individual animal species, at present 90% of the critically endangered
species are present in the zoos alone.
GENE BANKS: These are the store houses
which are maintained under controlled temperature conditions, and in general
the seeds of different species are stored.
Under such controlled conditions the
preservation of seeds can be done for 100’s of years.
Ex: Svalbard seed vault (Norway) has got
all known variety of seeds. àNational
seeds bank is also established in Lehn.
BOTANIC GARDENS: These are also called
as the field gene banks 1600 BG’s in world. Usually the plants that doesn’t
produce seeds or the seeds which doesn’t germinate are conserved in the
botanical gardens and the nurseries etc.
CAPTIVE BREEDING PROGRAM: The wild is
very vast and the due to the depletion of species, there are no potent mates
available for reproduction and the hence the animals are put together and are
seen that they mate.
THE CRYO PRESERVATIONS: It includes the
low temperature preservations, where the organs or the tissues are preserved in
the liquid nitrogen at -172 c.
TISSUE CULTURE: This includes the
growing of plants in the laboratories, may be in the test tube or conical
flashes etc in the nutrient agar medium.
It is a type asexual reproduction, where
the mass cloning of the single plant is multiplied either from the leaves or
the stem etc.
IN SITU METHODS:
On the site, in the place which use the
conservation areas as warehouses of biological information.
In situ methods are generally recognized
as being more secure and financially efficient. The main conservation
strategies includes
Expansion of the protected area network,
in the form of national parks, sanctuaries and bio reserves etc.
This facilitates the gene flow through
the creation of corridors, introduction of new genetic stock, translocation of
the animals etc
Establishing minimum target population
goals
Distributing founders through the
captive breeding programs.
Improved protection efforts and
landscape approach to conservation
Mapping the distribution of habitat type
Establishment of associating groups of
species with different landscape elements.
Assessing the threats to the species
because of on going commercial landscape changes.
Assigning conservation priorities to
species on the basis of threats, rarity, endemism and taxonomic
distinctiveness.
Assigning conservation priorities of
different types of habitats etc.
INDIAN
BIODIVERSITY
India is the one of the 8 vavilovians
centers ( origin of wild ancestors)
It ranks in top 10 species rich nations
of the world.
India offers a wide range of habitat
types with large variety of biodiversity.
According to IUCN of nature and natural
resources, world conservation union, India has a total of 91,200 species of
animals, 45,500 species of plants, à
species of birds ( 9th in world); à500
species of mammals (7th in world);à
100’s species of reptiles(5th in world and is 47%);à
100’s of species of amphibians (7th in position its 61.2% of the
world total)
Nearly 15% of the Indian
biodiversity is considered as “endemic”
i.e these species are local and not found in other parts of the world.
The great problem faced by the
biodiversity of India is that they are either 1. Getting endangered or2. In the
stage of extinction.
ENDANGERED SPECIES:
The species whose life is threatened and
known as endangered species. Ex: Indian
lion, snow leopard, wild buffalo, great Indian bustard, Nilghai, Niligiri
Langur, Bengal tiger, Kashmiri stag, Musk deer, cheetah, wildars and the
Gazelle etc
According to the Red data book of IUCN
INDIA has 413 globally threatened species it is 4.9% of the world’s total.
The fast dwindling of the forest of
western ghats and Himalayas etc , the human activities is adversely affecting
the biodiversity and this trend is disturbing the ecological balance.
RED
DATA BOOK:
The IUCN is now called as the world
conservation union, it has its headquarters at Morges, Switzerland is
maintaining the “Red book data” or “red list”, which is a catalogue of
taxa(species) facing risk of extinction.
The red book was initiated in 1963 to
provide the
a)The awareness of threat to
biodiversity
b)Provide a global index about already
declined biodiversity
c)Guidelines for identification and
documentation of species which are at high risk of extinction and for preparing
conservation priorities and help in conservation action
d)To have the information about
international agreements like convention on biological diversity CBD and the
convention on international trade in endangered species of wild fauna and flora
cities etc.
Red list 8 categories of species:
EXTINCT: The taxon which have been
completely eliminated or died out from earth. Ex: dodo.dinasaurs
EXTINCT IN WILD: The taxon is absent in
any of its natural or expected habitats in the wild. A number of domesticated
animals and plants have become extinct in the wild.
CRITICALLY ENDANGERED: The taxon is
facing very high risk of extinction in the wild and can become extinct in any
moment in the immediate future.
Their number worldwide is 925 animals
and 1014 plants (10%-mammals, 9%-birds, 15%-reptiles, 16%-amphibians, 16%-
angiosperms). The number of critically endangered animals and plants in India
is 18 and 44 respectively.
Ex: sus salvanius (pigmy, hog) berberis,
nilghirienris, podo-phyllum etc
ENDANGERED: It is facing a high risk of
extinction in the wild in the near future due to either
a)Decrease in its habitat
b)Excessive predation
c)Poaching etc
In India 54animals and 113 plants are
endangered.
Ex: The Asiatic wild ass( asinus hemionus
khur) restricted to Runn of Kutch, the
lion tailed macaque etc
VULNERABLE: Presently the population is
sufficient, but if proper careis not taken they may undergo depletion.
Out of the total threatened species
34-51% are vulnerable with 34% mammals, 36% birds, 43% reptiles, 48%
amphibians, 51% angiosperms.
In India their number is 143 animals and
87 plants. Ex: antelope cervicapra (black buck); cupressus cashmeriana- Indian
gazelle etc
LOWER RISK: They are the threatened
species which have lower risk of extinction, with less attention they become
normal flourishing species
The percentage of lower risk species,
out of the total threatened ones is 37% mammals, 38%-birds, 21% reptiles,
16%amphibians, 14% angiosperms. In India their number is 109 animals, 73 plant
species.
DATA DEFICIENCY: The data for making
direct and indirect assessment of risk of extinction is deficient.
NON EVALUTED: The taxon has not been
evaluated for risk or extinction.
EFFORTS:
International efforts for conserving the
biodiversity several, international agreements and global initiatives have
focused on bio conservation like “ Earth summit” at Rio de Janerio 1992 Brazil
promoted convention on biological diversity CBD”
UNESCO United nations educational
scientific and cultural organization, in 1971 has began the man and the
biosphere program aimed to improve relationship
The plan was to establish at least one
(ideally 5 or more), biosphere reserves in each of the Earths 193 bio-geographical
zones.
Convention concerning the protection of
the world cultural and natural heritage, it was adopted by
UNESCO 1972
It seeks to encourage the
identification, protection and preservation of cultural and natural heritage. A
number of sites in the heritage list are the nature parks, reservoirs etc, that
conserve biodiversity.
RAMSAR: This is the convention for the
protection of wet lands in Iran-1971
CITIES: Convention and international
trade in endangered species wild fauna and flora has begun in 1975 with 21
countries.
But by 2010-175 signatories were
present. This bans the hunting capturing and selling of the endangered or
threatened species.
It lists over 900 species of live
specimen or wild life products cannot be traded.
It restricts the international trade of
29000 other species that are potentially threatened.
UNCLOS: United nation’s convention on
the law of the sea. This is to protect the marine biodiversity of accounting.
In 1980 three organizations, they are
UNEP, ICUN, WWF
(a)UNEP: United nation’s environment
program
(b)IUCN: International union for
conservation of nature and natural resources
(c)WWF: World wild fund for nature have
prepared a world conservation strategy.
The plan was to conserve biodiversity,
preserve vital ecosystems and their processes and develop sustainable uses of
organisms.
CBD: Convention on biological diversity
was approved in 1992 at the Earth summit and came into force in 1993.
As on 2010 end 193 countries are parties
to the convention. It has 3 goals
Conservation on biodiversity
Sustainable use of components of
biodiversity
Nagoya program: It is on access to
genetic resources and the fair and equitable sharing of benefits from their
utilization, 29th,oct,2010
Sharing the benefits using from the
commercial and other utilization of genetic resources in a fair and equitable
way
It is the main international agreement
for conserving global biodiversity because of the abundant diversity,
conservation is important for not only for the country but also for the rest of
the world and India is the secondary home for species.
CARTAGENA PROTOCOL: (On biosafety) this
aims the safe handling of the bio aspects, while they are in transit, UN
Nairobi office in 2000 with 166 signatories.( NGO- GREEN PEACE)
ICCMSB: International convention for the
control and management of ships ballast water and sediments are adapted by 75
countries in 2004
Under this convention ships must have
facilities to treat the ballast water before releasing them into foreign water.
NATIONAL EFFORTS FOR CONSERVATION:
India is a particularly and signatory
country to all the major international conventions, the protocols and programs
for conserving the biodiversity.
As soon as the idea was mooted by UN, India actively participated and
also brought out several acts for protecting biodiversity like:
National board for wild life 1952, for
protection and conservation of wild life and to advice the government for
constitution of national parks, sanctuaries and zoological gardens along with
promoting public awareness
Under this board 99- national parks, 515
wild life sanctuaries, 53 tiger reserves, 18 biospheres, 19 zoological parks
were been established.
Wild life protection act,1972: for
conservation of wild life, protection of endangered species, breeding programs
for endangered species, control of poaching and illegal trading of wildlife etc
Project tiger: it was launched in 1973
because the tiger population dwindled from 40,000 in the beginning of 20th
century to just 1700 in 2010
There are 53 tiger reserves of which 17
are getting 100% cental assistance (largest Nagarjuna sagar).
National wildlife action plan: it was
adopted in 1983. It provides framework and program for wildlife conservation
Project elephant was launched in 1992
and implemented in states and UT’S.
Wildlife crime control bureau-2008 was
established.
Integrated forest protection scheme was
introduced in 10th five year plan.
It has been renamed as the
intensification of forest management in 11th five year plan, for
conserving the uniue vegetation and ecosystem.
National biodiversity act came into
effect from 2002.
BIOSPHERE
The biosphere program is a part of
international program, its idea was mooted by UNESCO in 1973-74
AIMS: For preserving the genetic
diversity and integrity of all living organisms
To provide education on environmental
awareness, for the initiation of ecological developmental process.
The 1st biosphere zone
identified in India was Niligiris-1984, subsequently 17 more were added to the
list and at present there are 18 biospheres in India, they are
Niligiri- 1984 -
TAMILNADU- 5500
Nokrek- 1988- Meghalaya- 800
Nandadeir- 1988 – UK- 5900
Great Nicobar- 1989- A&N-
900
Gulf of mannar- 1989- TN- 10500
Manas- 1989-
ASSAM-2800
Sunderbans- 1989- WB- 9600
Simlipal- 1994- ORISSA- 4400
Dibru-saikhowa- 1997- ASSAM- 770
Dehang – debang- 1998- AR.P- 5100
Panmarhi or pach man – 1999- MP- 4900
Kanchanjunga- 2000- SIKKIM- 2600
Agasthyamalai- 2001- KERELA- 1800
Achanakamar-Amarkantak- 20 05-MP-CHATTISGARH-
3800
Kutch- 2008- GUJARAT- 12500
Pin valley national park( cold desert)- 2009- HP-
Seshachalam hills- 2010-
AP-
Panna-
2011- MP
Each biosphere reserve has
a)Core and natural zone: no human
activity
b)Buffer zone: limited human activity is
allowed
c)Transition zone: it is also called
manipulation zone. In this zone there is
active cooperation present between the local and forest officials for
doing certain economic activities without disturbing ecology
The 1st protected area was
the Hailey National park i.e.,JIM CORBETT National park which was established
in 1935-36 in UK.
The biosphere is put under 3rd
category of protected areas
MAN AND BIODIVERSITY PROGRAM:
It is an intergovernmental scientific
program for the improvement of the relationship between the people and
environment, launched in 1970 and began in 1971.
Till 2010 there were 562 biosphere
reserves present in 109 countries.
4 of the India’s biospheres were
included in the world network of biosphere reserves they areà
Suderbans, Gulf of Mannar, Nilgiri, Nandadevi
4 more are considered for inclusionàManas,
Simlipal, Pachmarhi, Kanchenzonga.