THE HIMALAYA REGION

ALTITUDE INFLUENCES THE FLORA AND THE FAUNA IN THIS REGION. THE CLIMATIC CONDITIONS SIMILAR TO THE ARCTIC REGIONS  ARE FOUND AT HIGHER ELEVATIONS OF THE HIMALAYAS.APART FROM THE ECOLOGICAL CHANGES DUE TO ALTITUDE IN THE HIMALAYAS, THERE IS A MARKED EAST-WEST VARIATION DUE TO THE WEST- WARD DECREASE IN THE MONSOON RAINFALL. THE WESTERN HIMALAYAS HAVE LOW BUT HEAVIER SNOWFALL AS COMPARED TO THE EASTERN HIMALAYAS WHILE RECEIVE MUCH MORE RAINFALL AND SNOWFALL ONLY IN THE VERY HIGH ALTITUDES. THE CLIMATIC CONDITIONS OF THE LOWER ALTITUDES OF THE EASTERN HIMALAYAS RESEMBLE THAT OF THE TROPICAL RAIN FOREST. THE TEMPERATE REGION IN THE EASTERN REGION STARTS  ABOVE 2745 METERS AS AGAINST 1500 METERS IN THE WESTERN HIMALAYAS.

ECOLOGICAL SUB-DIVISIONS

THE PRESENT PHYSICAL FEATURES AND CLIMATE OF INDIA TOGETHER WITH THE IMMENSE FAUNA CHANGES THAT TOOK PLACE DURING THE LATE PLIOCENE PERIOD HAVE IMPARTED TO ITS FLORA AND FAUNA, A WIDE VARIETY OF HABITATS, EACH SUPPORTING ITS DISTINCTIVE TYPE OF FLORA AND FAUNA.

INDIA AS A MEGA DIVERSITY NATION

THE GREAT VARIETY OF ECOLOGICAL CONDITIONS PREVAILING IN INDIA ALLOWS IT TO SUPPORT AN ENORMOUS DIVERSITY OF WILD LIFE, INCLUDING, HOT DESERT FORMS, LIKE THE WILD ASS AND THE COLD DESERT FORMS, LIKE THE TIBETAN ANTELOPE; ANIMALS OF OPEN SCRUBLAND, LIKE THE RHINOCEROS; ANIMALS OF THE DECIDUOUS FORESTS LIKE THE WILD GAUR AND OF THE TROPICAL RAIN FORESTS, LIKE THE LION-TAILED MACAQUE.


THE UNIQUE BIO-GEOGRAPHIC POSITION OF THE INDIAN SUBCONTINENT IS RESPONSIBLE FOR THE GREATER DIVERSITY IN INDIA'S WILDLIFE. INDIA LIES AT THE CONFLUENCE OF ETHIOPIAN, PALAEARCTIC AND INDO- MALAYAN FAUNAS AND POSSESS A NUMBER OF INTERESTING COMPONENTS FROM EACH OF THESE REALMS AS WELL AS SEVERAL INDIGENOUS VARIETIES. THE ETHIOPIAN ELEMENT IS REPRESENTED BY THE CHINKARA, THE HYENA AND THE RATEL; THE PALAEARCTIC BY THE LYNX, WOLF, HANGUL; THE CHINESE, BY RED PANDA AND MUSK DEER AND THE INDO-MALAYAN BY THE HOOLOCK GIBBON, THE ELEPHANT, THE GOAT ANTELOPE AND THE MOUSE DEER. THE ENDEMIC VARIETIES INCLUDE MELURSUS(SLOTH BEAR), ANTELOPE (BLACK BUCK), TETRACERUS (FOUR-HORNED ANTELOPE) AND BOSELAPHUS (NILGAI).


THE PRESENCE OR ABSENCE OF AN ANIMAL OR PLANT IN A CERTAIN REGION IS DETERMINED  BY ECOLOGICAL AND HISTORICAL FACTORS. POPULATIONS OF ORGANISMS CAN BE ESTABLISHED IN A REGION ONLY IT THE RANGE OF CONDITIONS PREVAILING THERE. ANIMALS AND PLANTS THEN ARE LIVING INDICATORS OF THE CHARACTERISTICS OF THEIR ENVIRONMENT. THEIR RANGES MARK THE PLACES IN WHICH ENVIRONMENTAL CONDITIONS ARE SIMILAR. AT THE SAME TIME, THE EVOLUTION  AND DISTRIBUTION OF SPECIES CASTS LIGHT UPON THE GEOLOGICAL EVOLUTION OF VARIOUS PARTS OF THE EARTH, AND UPON THE COURSE OF GLOBAL CHANGES IN CLIMATE AND VEGETATION.

ALLELOCHEMISTRY

THESE RELATIONSHIPS INVOLVE COACTIONS  WHEREBY CHEMICALS SECRETED BY ONE ORGANISM AFFECT THE GROWTH, HEALTH AND BEHAVIOUR OF OTHER ORGANISMS. ALLELOPATHY IS PRODUCED IN  PLANTS  WHEN TOXINS ARE LIBERATED THAT INHIBIT SEEDLING GROWTH IN THE VICINITY. THIS MAY AFFECT SUCCESSION IN PLANT SPECIES  ESPECIALLY IMPORTANT IN THE EARLY STAGES.ANTIBIOTICS PRODUCED BY BACTERIA, FUNGI AND LICHENS  ARE WIDESPREAD IN NATURE. ALLECHEMIC EFFECTS ARE  OF GREAT VARIETY IN BOTH PLANTS AND ANIMALS: REPELLANTS, ESCAPE SUBSTANCES, SUPPRESSANTS, VENOMS, INDUCTANTS, ATTRACTANTS, SIGNALS, STIMULANTS, AUTOTOXINS, ANTOINHIBITORS, ETC. PHEROMONES, CHEMICAL MESSAGES BETWEEN  MEMBERS OF A SPECIES ARE ESPECIALLY IMPORTANT IN REPRODUCTIVE BEHAVIOUR, SOCIAL  REGULATION AND RECOGNITION, ALARM AND DEFENCE, TERRITORY AND TRAIL MARKING, FOOD  LOCATION AND SO ON.

AGGREGATIONS

THE REACTIONS MADE BY LARGE POPULATIONS ON THEIR HABITAT SHOW CONSPICUOUS EFFECTS. DUE TO THE OCCURENCE OF WATER CONDITIONING, PHYSICAL AND CHEMICAL CHANGES OCCUR AS A RESULT OF ORGANISMS LIVING IN IT. COMPARED TO UNCONDITIONED WATER, THESE CHANGES MAY EITHER PROVE TO BE HARMFUL OR BENEFICIAL ON THE ORGANISMS INTRODUCED INTO THE WATER AFTER THE ORIGINAL ORGANISMS HAVE BEEN REMOVED. THE MARINE FLATWORM WILL SURVIVE MUCH LONGER, WHEN TRANSFERRED TO FRESH WATER CONDITIONED EITHER BY THE PRESENCE OF LIVING OR DEAD  INDIVIDUALS  OF THE SAME SPECIES OR BY THE PRESENCE OF FRESH WATER SPECIES OF FLATWORMS, THAN THEY DO IN UNCONDITIONED WATER. AGGREGATIONS ENSURE  LONGER SURVIVAL  OF ORGANISMS IN TOXIC  SOLUTIONS  THROUGH FASTER GROWTH AND GREATER REPRODUCTION.

BENEFITS DERIVED FROM AGGREGATIONS IN TERRESTRIAL ANIMALS ARE ALSO WELL DEPICTED IN HONEYBEES WHEN THEY FORM CLUSTERS AND MAINTAIN  A MASS TEMPERATURE SEVERAL DEGREES ABOVE OUTSIDE TEMPERATURES. WHEN THERE IS DANGER OF OVERHEATING, THE BEES IN THE HIVE SPREAD OUT ON THE COMBS AND FAN WITH THEIR WINGS TO CREATE A CIRCULATION OF AIR.

COMPETITION

THE WORD COMPETITION DENOTES STRIVING FOR THE SAME THING. AT THE ECOLOGICAL  LEVEL IT HOLDS GREAT RELEVANCE WHEN THE THING WHICH TWO ORGANISMS ARE STRIVING FOR IS NOT EASILY AVAILABLE. EVEN IF AVAILABLE, IT IS ONLY IN SMALL NUMBERS. IF POPULATION CONSISTS OF ONLY A FEW SCATTERED INDIVIDUALS COMPETITION WILL NOT BE A FACTOR OF ECOLOGICAL IMPORTANCE.

THE RESULT OF COMPETITION IS THAT BOTH PARTIES  COMPETING WILL BE HAMPERED IN SOME MANNER OR THE OTHER. AT THE POPULATION LEVEL, OR THE DESTINY OR RATE OF POPULATION, ENERGY  FLOW WILL BE REDUCED OR HELD IN CHECK BY THE COMPETITIVE ACTION. COMPETITION ALSO OCCURS WHEN TWO ORGANISMS STRIVE FOR SOMETHING THAT IS NOT IN SHORT  SUPPLY, YET THEY INTERFERE WITH EACH OTHER, OR THEY MIGHT EVEN EAT EACH OTHER. MANY ECOLOGISTS PREFER NOT TO  INCLUDE  THIS ASPECT UNDER COMPETITION.

PLANT POPULATION AS WELL AS ANIMAL POPULATION MAY REGULATE THEMSELVES TO AVOID OVER-CROWDING. DESERT SHRUBS ARE WIDELY SPACED, ALMOST UNIFORMLY DISTRIBUTED; THIS PATTERN EXPLAINS THE COMPETITION OF SCARCITY OF WATER.HOWEVER, EVOLUTION OF SELF REGULATION OF POPULATION HAS OCCURRED IN SOME SPECIES IN THAT SEVERE COMPETITION FOR WATER IS AVOIDED BY THE PRODUCTION OF LEAF OR ROOT HORMONES THAT INHIBIT DEVELOPMENT OF OTHER INDIVIDUALS IN THE NEIGHBOURHOOD.

AMENSALISM AND ANTIBIOSIS

AMENSALISM IS A SITE-SPECIFIC RELATIONSHIP IN WHICH ONE POPULATION IS INHIBITED WHILE THE OTHER IS UNAFFECTED. A SIMPLE EXAMPLE IS THE SHADING OUT OF CERTAIN PLANTS UNDER TALL TREES. THE TREES REDUCE THE AVAILABLE SUNSHINE AT GROUND LEVEL, AND NUMEROUS PLANTS CANNOT FIND ADEQUATE LIGHT IN THE SHADE. HENCE, ONLY SHADE TOLERANT PLANTS WITH LOWER LIGHT REQUIREMENTS CAN SURVIVE AS GROUND COVER IN THE FORESTS.

ANTIBIOSIS IS A SPECIFIC TYPE OF AMENSALISM IN WHICH ONE ORGANISM PRODUCES A METABOLITE THAT IS TOXIC TO OTHER ORGANISMS. THE BEST KNOWN EXAMPLE IS MOLD, PENICILLIN, WHICH PRODUCES AN ANTIBIOTIC SUBSTANCE  CAUSING THE DEATH OF MANY BACTERIA. MANY PLANTS ALSO PRODUCE SUBSTANCES  WHICH ARE HARMFUL TO ANIMALS, FOR EXAMPLE, ALGAE BLOOMS OF SOME BLUE, GREEN AND RED ALGAE PRODUCE CHEMICALS THAT ARE TOXIC TO FISH.

PROTOCOOPERATION

IT IS A SHORT STEP AHEAD OF COMMENSALISMS AND COOPERATION. IN THIS RELATIONSHIP, BOTH ORGANISMS GAIN BY THE ASSOCIATION AND ARE MUTUALLY BENEFITTED. THE RED-BILLED OXPECKER FORM PROTOCOOPERATION WITH THE BLACK RHINOCEROS- THE BIRDS FEED ON THE PARASITES STICKING ON THE SKIN OF THE RHINOCEROS RELIEVING HIM OF THE PARASITES STICKING ON THE SKIN OF THE RHINOCEROS RELIEVING HIM OF THE PARASITES, AND IN TURN  OBTAINING THEIR FOOD.

PARASITISM

IT IS THE RELATIOSHIP BETWEEN TWO INDIVIDUALS OF DIFFERENT SPECIES IN WHICH THE PARASITE RECEIVES BENEFIT AT THE EXPENSE OF THE HOST; THEREFORE , PARASITISM IS A FORM OF THIS OPERATION. IN THIS  ASSOCIATION, THE PARASITE RECEIVES FOOD, SHELTER AND PROTECTION AT THE EXPENSE OF THE HOST.

THE ORIGIN OF A PARASITIC LIFE IN AN ANIMAL IS ASSOCIATED WITH ATTEMPTS TO SECURE FOOD FOR THEMSELVES OR THEIR OFFSPRING. THE ANCESTORS OF ECTOPARASITES  WERE CLEARLY FREE LIVING FORMS. A FREE LIVING ORGANISM COULD HAVE ACCIDENTALY SETTLED ON THE BODY OF A LARGER SPECIES WHERE CONDITIONS WERE MORE FAVOURABLE FOR SURVIVAL. THERE ARE CERTAIN MODIFICATIONS AND ADAPTATIONS WHICH MIGHT HAVE EVOLVED  IN THESE ORGANISMS.

ORGANS OF ATTACHMENTS: THE TAPEWORM HAS HOOKS FOR ATTACHMENT TO THE HOST'S GUT WALL.


BODY SHAPE: THE INTESTINAL PARASITES LIKE THE ROUND WORM HAS AN ELONGATED BODY.


CUTICLES: THE INTESTINAL PARASITES LIKE THE  TAPEWORM HAVE THICK CUTICLES WHICH OFFER THEM  RESISTANCE AGAINST THE ACTION OF THE DIGESTIVE JUICES.


LOSS OF LOCOMOTARY ORGANS: MOST ENDOPARASITES LIKE FLEAS (THEY HAVE LOST THEIR WINGS, HAVE LOST THEIR LOCOMOTIVE ORGANS AS THEY ARE NOT NEEDED. THESE ORGANS MAY DISAPPEAR OR DIFFERENTIATE  INTO ORGANS OF ATTACHMENTS.


LOSS OF SENSE ORGANS: AS THE INTERNAL ENVIRONMENT OF THE HOST  IS MORE OR LESS UNIFORM, THERE IS NO USE OF SENSE ORGANS AMONG ENDOPARASITES AS THEY ARE  PROVIDED ONLY WITH TANGO RECEPTORS.


DIGESTIVE SYSTEM: THE TAPEWORM HAS LOST ITS DIGESTIVE SYSTEM, ITS MOUTH PARTS  HAVE DEVELOPED PIERCING AND SUCKING APPARATUS TO CONSUME THE ALREADY DIGESTED FOOD.


COMPLICATED REPRODUCTION : THE ROUNDWORM IN HUMANS LAYS EGGS AT THE RATE OF 1500 A DAY, THE TERMATODES LAY EGGS CONTINUOUSLY, AND THE TAPEWORM LAYS EGGS ANNUALLY, ESTIMATED AT 80 MILLION PER YEAR.

THE EFFECT OF PARASITISM ON THE HOST IS USUALLY HARMFUL. THE EFFECT OF PARASITISM ON THE HOST IS USUALLY HARMFUL. THE EFFECTS OF ENDOPARASITES ARE MORE MARKED THAN THOSE ECTOPARASITES.

PREDATION

IN THIS RELATIONSHIP THE PREY IS KILLED BY ONE ANIMAL AND EATEN BY ANOTHER, THE PREDATOR. A PREDATOR IS A FREE LIVING ANIMAL USUALLY LARGER THAN ITS PREY. PREDATORS ARE MOSTLY CARNIVORES. HERBIVORES ANIMALS THAT EAT PLANTS OR SEEDS OF PLANTS ARE ALSO IN A WAY PREDATORS BECAUSE THEY REMOVE INDIVIDUALS  FROM THE POPULATION. SOME PLANTS PREDATORS ARE CALLED CARNIVORES OR INSECTIVOROUS, FOR EXAMPLE UTRICULARIA, DIONAEA, ETC. SOME PREDATORS FUNCTION AS PREYS FOR OTHERS, EXAMPLE FROG THAT FEEDS ON INSECTS IS A PREY FOR AN EAGLE OR A PEACOCK. IN NATURE THE POPULATION OF PREDATORS IS QUITE SMALL AND THAT OF PREY IS MUCH LARGER SO THAT THE LATTER IS NEVER ELIMINATED COMPLETELY.

COMMENSALISM

THIS TYPE OF RELATIONSHIP IS ESTABLISHED WHEN TWO OR MORE ORGANISMS LIVE TOGETHER WITHOUT HAVING ANY PHYSIOLOGICAL UNION. THE RELATION IS UNEQUAL IN THAT ONLY ONE INDIVIDUAL GETS THE BENEFIT FROM THE ASSOCIATION WHILE THE OTHER REMAINS UNAFFECTED.

THE CHIEF BENEFITS OF THIS ASSOCIATION ARE SHELTER, ANCHORAGE , TRANSPORTATION AND FOOD SUPPLY. A COMMENSAL THAT ATTACHES  OR LIVES  UPON THE HOST'S BODY IS CALLED ECTOCOMMENSAL. A COMMENSAL THAT LIVES INSIDE THE BODY OF THE HOST IS REFFERED TO AS AN ENDOCOMMENSAL. SUCKER FISH IS AN ECTOCOMMENSAL THAT ATTACHES ITSELF TO THE BODY OF A SHARK. ALL THE ECTOCOMMENSALS ARE SMALL IN SIZE AND NOT BURDENSOME TO THE HOST. THE HARMLESS PROTOZOAN IN THE INTESTINAL TRACT OF MAMMALS AND MICRO-ORGANISMS IN THE CANAL SYSTEM OF SPONGES ARE EXAMPLES OF ENDOCOMMENSALS.

MANY LARGE TROPICAL TREES PROVIDE HABITATS FOR NUMEROUS COMMENSAL PLANTS AND ANIMALS. TRUNKS AND BRANCHES PROVIDE ATTACHMENT SITES FOR PLANTS SUCH AS ORCHIDS. ATTACHMENT HARBOURAGE  IS PROVIDE BY THE TREES FOR BATS, TREE FROGS, LIZARDS, INSECTS AND MANY OTHER ANIMALS. WHALES PROVIDE ATTACHMENT SITES FOR BARNACLES, ALGAE, ETC. THESE PLANTS AND ANIMALS ARE NOT PARASITIC.

ANOTHER COMMON TYPE OF COMMENSALISMS OCCURS WHEN VARIOUS SPECIES OF PLANTS AND ANIMALS USE BURROWS OR NESTS CONSTRUCTED BY OTHER SPECIES . TERMITE NESTS PROVIDE ECOLOGIC NICHES  FOR MORE THAN A HUNDRED SPECIES OF OTHER ANIMALS SUCH AS ANTS, BEETLES AND MILLIPEDS.

SYMBIOSIS

SYMBIOSIS IS AN ASSOCIATION BETWEEN TWO OR MORE ORGANISMS THAT LIVE TOGETHER IN CLOSE PHYSIOLOGICAL UNION FOR MUTUAL BENEFIT. IN THIS DEFINATION, SYMBIOSIS REFERS TO THE INTIMATE ASSOCIATION OF TWO DIFFERENT KINDS OF ORGANISMS.

THE IMPORTANCE OF NITROGEN FIXING BACTERIA, RHIZOID ASSOCIATED WITH LEGUMES IS WELL KNOWN. ROOTLETS OF LEGUMES HAVE SWELLINGS,INHABITED BY BACTERIA. HERE, THEY DERIVE CARBOHYDRATES FROM THE HOST AND IN TURN THEY FIX  THE ATMOSPHERIC NITROGEN IN THE ROOTS. THIS NITROGEN IS USED BY PLANTS.

THE WOOD BORING BEETLES HAVE AN ELABORATE APPARATUS  ON THEIR HEADS FOR CARRYING THE FUNGUS. THE FEMALES  OF THESE SPECIES HAVE AN APPARATUS CONNECTED WITH OVIPOSITOR WHICH COATS THEIR EGGS WITH FUNGAL SPORES AS THEY ARE LAID. IN ALL THESE  ASSOCIATIONS, THE FUNGUS  PROVIDES FOOD AND SHELTER, AND IT THRIVES ON THE EXCRETORY  MATERIAL OF ITS HOST.

MUTUALISM AND SYMBIOSIS ARE THE TERMS  APPLIED TO VERY SIMILAR TYPES OF ASSOCIATIONS WHERE, ONE DERIVES  NUTRITION  FROM ANOTHER AND IN TURN BENEFITS THE FOOD SUPPLIER IN SOME OTHER WAY. FOR EXAMPLE , IN LICHENS  THE  ALGAE PROVIDES PART OF FOOD FOR CONSUMPTION BY THE FUNGAL COMPONENT. IN TURN THE FUNGUS PROVIDES PROTECTION TO THE ALGAE AGAINST DESICCATION. MANY OF THESE RELATIONSHIPS AND TERMINOLOGIES OF BIOTIC COMPONENTS ARE BASED ON FOOD HABITS.

MUTUALISM

THERE ARE CERTAIN TYPES OF CLOSE BIOTIC INTERDEPENDENCE AMONG THE SPECIES LIVING IN AN ECOSYSTEM SUCH AS-MUTUALISM, WHICH IS AN ASSOCIATION BETWEEN TWO OR MORE ORGANISMS IN WHICH ALL DERIVE MUTUAL BENEFIT WITH NO HARM TO ANY OF THE PARTNERS. MUTUALISM CAN BE SEEN BETWEEN PLANTS AND ANIMALS AND BETWEEN TWO DIFFERENT ANIMALS.


MUTUALISM BETWEEN PLANTS AND ANIMALS : IT IS AN IMPORTANT ASSOCIATION WITH REGARDS TO REPRODUCTION OF MANY KINDS OF PLANT SPECIES. PLANTS ATTRACT INSECT BY THERE SWEET NECTAR OR COLOUR. THE INSECT VISIT THE PLANTS TO OBTAIN THEIR FOOD. THE PLANTS DUST THEM WITH POLLEN AND THE INSECTS CARY THE POLLEN FROM FLOWER TO FLOWER. PLANTS ALSO TAKE THE HELP OF ANIMALS IN THE DISTRIBUTION OF SEEDS. ANIMALS, AFTER CONSUMING THE FRUITS, DISTRIBUTE THE HARD COATED SEEDS WHICH PASS THROUGH THEIR ALIMENTARY CANAL, IN THEIR DROPPINGS.


MUTUALISM BETWEEN ANIMALS AND OTHER ANIMALS : MUTUALISTIC ASSOCIATES BETWEEN BIRDS AND ANIMALS SUCH AS, THE COW BIRD AND BISON, THE OXPECKER AND THE ANTELOPE,  THE CROW AND THE CATTLE, DISPLAY SUCH RELATIONSHIP. IN ALL THESE RELATIONSHIPS THE BIRDS RENDER CONSIDERABLE SERVICE TO THEIR HOST BY RIDDING THEM TO TICKS AND EXTERNAL PARASITES. THEY ALSO SERVE AS SENTINELS. IN TURN THE BIRD RECEIVES A CONSTANT SUPPLY OF FOOD.


AN INTERESTING EXAMPLE IS BETWEEN THE CROCODILE AND THE BIRD, PLUVIANUS AEGYPTIUS. THE BIRD REMOVES LEECHES AND FRAGMENTS OF FOOD IN DECAYING CONDITION FROM THE CROCODILE. THE CROCODILE OPENS ITS JAWS AND PERMITS THE SEARCH AND THEN FINALLY THE BIRD RECEIVES THE FOOD FROM THE CROCODILE. THE COMMON STARLING BIRD ALSO PERFORMS THE SAME FUNCTION WITH THE SHEEP.


SPONGES GROWING ON THE SHELL OF THE HERMIT CRAB PROTECT IT BY PRODUCING BAD ODOUR. HERE THE ADVANTAGE TO THE SPONGE IS THAT, IT IS CARRIED TO NEW WATERS FOR ITS OWN FOOD. THUS, THE MUTUALISTIC RELATIONSHIPS BETWEEN PLANTS AND ANIMALS AND ANIMALS SHOW THEIR INTERDEPENDENCE FOR MUTUAL BENEFITS.


MUTUALISM MAY BE OBLIGATORY OR FACULTATIVE. AN EXAMPLE OF OBLIGATORY  MUTUALISM OCCURS BETWEEN A HORSE AND CERTAIN MICRO-ORGANISMS. MILLIONS OF CILITATE PROTOZOA AND BACTERIA LIVE IN THE STOMACH AND CAESUM OF A HORSE WHICH DIGEST CELLULOSE FOR THE HORSE  AND PROVIDES 20 PERCENT OF ITS NITROGEN REQUIREMENT PER DAY.THESE INTESTINAL MICRO-ORGANISMS ARE ESSENTIAL FOR THE NORMAL GROWTH AND HEALTH OF THE HORSE.


MANY MUTUALISTIC RELATIONSHIPS ARE FACULTATIVE, I.E., BOTH ARE FAVOURED WHEN LIVING TOGETHER. THOUGH BABOONS AND IMPALAS CAN SURVIVE WELL WITHOUT EACH OTHER, BUT EACH PROVIDES A PROTECTIVE WARNING SYSTEM  FOR THE OTHER WHEN THEY LIVE IN ASSOCIATION. SQUIRRELS FACILITATE THE EXTENSION OF THE HISKORY TREE  BY BURYING THE NUTS, THOUGH THE HISKORY TREE CAN PROPAGATE WITHOUT SQUIRRELS. IN THE SAME MANNER, SQUIRRELS  CAN SURVIVE WITHOUT HISKORY NUTS, IF AN ADEQUATE SUPPLY OF OTHER NUTS IS AVAILABLE.


MAN HAS CAPITALIZED ON MUTUALISM AS BIOLOGICAL  PRINCIPLE IN THE DEVELOPMENT OF AGRICULTURE. DEVELOPMENT OF AGRICULTURE RESULTED IN THE RELATIONSHIP OF FACULTATIVE COMMENSALISMS OR MUTUALISM OF PLANTS AND ANIMALS WITH MAN. AT THE DRAWN OF AGRICULTURE 10,000 YEARS AGO, MAN COULD LIVE WITHOUT DOMESTICATION OF PLANTS AND ANIMALS, BUT AS HE DEVELOPED THESE RELATIONSHIPS HE GOT INVOLVED IN OBLIGATORY MUTUALISM. MODERN MAN OBVIOUSLY CANNOT LIVE WITHOUT THE DOMESTICATED PLANTS AND ANIMALS OF AGRICULTURE, AND MANY OF THESE DOMESTICATED FORMS CANNOT LIVE WITHOUT THE SPECIAL HUSBANDRY PROVIDED BY MAN.

SPECIES INTERACTIONS

ALL POPULATION OF LIVING ORGANISMS EXISTS IN A NETWORK OF INTERACTIONS WITH OTHER POPULATION. MANY OF THESE INTERACTIONS ARE SUBTLE AND COMPLEX WHILE OTHERS ARE DIRECT. THE DEGREE OF INTIMACY IN THE RELATIONSHIPS OF THE ORGANISM INHABITING A PARTICULAR HABITAT VARIES GREATLY. THESE ASSOCIATES MAY BE EITHER BENEFICIAL OR HARMFUL TO BOTH THE PARTNERS OR BENEFICIAL TO ONE PARTNER AND HARMFUL TO THE OTHER. IF THE RELATIONSHIP IS BENEFICIAL TO ONE OR BOTH PARTNERS, IT IS CALLED POSITIVE INTERACTION OR COOPERATION. THE INTERRELATIONS OF INDIVIDUALS THAT ARE HARMFUL TO ONE OR MORE OF THE PARTICIPANTS ARE CALLED NEGATIVE INTERACTION.

INTERACTIONS BETWEEN PLANTS AND ANIMALS

IN A NATURAL ECOSYSTEM THE SUN'S ENERGY WILL BE CAPTURED BY THE TREES, GRASS OR OTHER HERBS AND CONVERTED INTO PROTEINS, CARBOHYDRATES AND OTHER FOOD COMPONENTS. THESE WILL BE CONSUMED BY PLANT EATING MAMMALS, BIRDS, INSECTS AND A GREAT VARIETY OF OTHER ANIMALS WHICH IN TURN WILL PROVIDE FOOD FOR THE MEAT-EATING ANIMAL. ALL LIVING ORGANISMS ULTIMATELY PROVIDE FOOD FOR THE ORGANISMS OF DECAY WHICH BREAKS DOWN THE PLANT AND ANIMAL MATERIALS AND RESTORE THE CHEMICAL COMPONENTS OF THE SOIL.

HERBIVORES FEED ON DIFFERENT PARTS OF A PLANT AND ALSO ON DIFFERENT PLANTS. GRAZING ANIMALS EAT UNHARVESTED HERBS AND GRASSES WHILE BROWSING ANIMALS EAT FOLIAGE OF SHRUBS AND TREES. SHEEP PREFER BROWSING ON HIGH HERBS, GOATS AND DEER ON BROAD LEAVED SHRUBS, CAMELS ON TENDER SHOOTS OF TALL TREES, WHILE HORSES AND CATTLE PREFER GRASSES.GRAZING AND BROWSING IN LIMITED NUMBERS IS BENEFICIAL BECAUSE LIGNEOUS VEGETATION BECOMES DRY AND INFLAMMABLE DURING HOT SEASONS WHEN TEMPERATURES SHOOT UP. LIGHT TRAMPLING BY ANIMALS MIXES HUMUS AND LITTER . HERBIVORES ALSO KEEP A CHECK ON PLANT GROWTH. A NUMBER OF PLANTS GIVE SHELTER TO ANIMALS, BIRDS, INSECTS, REPTILES AND MICROBES APART FROM  PROVIDING THEM PALATABLE FOOD.

PLANTS MODIFY THE PHYSICAL ENVIRONMENT AND MAKE IT MORE CONGENIAL FOR HUMAN AND LIVING . THEY ACT AS WIND BREAKERS TO STORMS AND GALES THERE BY REDUCING THEIR VELOCITY, AND THUS REDUCING ENVIRONMENTAL DAMAGE, ESPECIALLY SOIL EROSION. PLANTS ALSO HELP IN MODERATING TEMPERATURE CONDITIONS, AND THROUGH TRANSPIRATION HELP IN BRINGING LOCAL RAIN. PLANTS ABSORB LARGE QUANTITIES OF WATER WHICH IN TURN PREVENTS WATER LOGGING OR FLOODING, IN CATCHMENT AREAS THEY RETAIN LARGE AMOUNTS OF WATER WHICH BECOMES AVAILABLE TO SPRINGS AND RIVERS. THE ROLE OF PLANTS IN NATURE AND ITS INHABITANTS IS INDISPENSABLE AS THEY ARE CLOSELY RELATED TO BOTH, THE BIOTIC AND ABIOTIC COMPONENTS OF THE ENVIRONMENT.

A NUMBER OF ANIMALS, ESPECIALLY INSECTS ARE INVOLVED IN POLLINATION OF FLOWERS. THEIR BODIES HAVE BEEN FRAMED TO SUCK NECTAR, EAT/COLLECT POLLEN GRAINS AND PERFORM POLLINATION. SOME FLOWERS ARE ALSO POLLINATOR SPECIFIC. FLOWERS OF SNAP DRAGON (DOG FLOWER) HAVE CLOSED LIP-LIKE PETALS WHICH OPEN ONLY WHEN AN INSECT LANDS OVER ITS LOWER LIP. THESE ARE THE MAJOR POLLINATORS OF CROP PLANTS. FRUITS AND SEEDS OF MANY PLANTS ARE DISPERSED BY ANIMALS ESPECIALLY BIRDS AND ANIMALS. IN MANY CASES PLANTS PROVIDE FOOD TO ANIMALS FOR THIS JOB. THE GALL WASP LAYS EGGS INSIDE THE LEAVES AND YOUNG STEMS TO ENSURE THEIR PROTECTION, HATCHING AND FEEDING.

INTERDEPENDENCE BETWEEN SPECIES

NO LIVING ORGANISM EXISTS IN COMPLETE ISOLATION FROM OTHERS PLANTS AND ANIMALS THAT LIVE IN A PARTICULAR PLACE SHARE THE SAME AIR , THE SAME ROCKS AND THE SAME NEIGHBOURS. THEY LIVE TOGETHER, AND THEY LIVE IN HARMONY. SOME FEED ON OTHERS, BUT THE LARGER PICTURE IS THAT OF OVERALL BALANCE. SCIENTIFIC STUDIES HAVE SHOWN THAT THIS BALANCE IS ACHIEVED  THROUGH  AN EXTREMELY COMPLEX NETWORK OF RELATIONSHIPS IS THAT OF PLANTS AND ANIMALS . WITHOUT PLANTS, ANIMAL LIFE WOULD  BE POSSIBLE . THE LIVING ORGANISMS IN A PHYSICAL ENVIRONMENT ARE INSEPARABLY INTERDEPENDENT AND INTERACT WITH EACH OTHER.

THE BIOSPHERE AND ITS FUNCTIONING

ECOSYSTEMS OF THE EARTH COLLECTIVELY FORM THE BIOSPHERE. IT IS A NARROW ZONE WHERE LIFE EXISTS. IT INCLUDES ALL OCEANS AND FRESH WATERS, THE LOWER LAYERS OF THE ATMOSPHERE AND THE OUTER SKIN OF THE EARTH'S CRUST WHICH IS MADE UP OF ROCKS AND SOIL.

MAN IS A PART OF THE BIOSPHERE AND DEPENDS ON ITS CONTINUED FUNCTIONING FOR HIS OWN EXISTENCE. HE CANNOT, HOWEVER, RISK MAJOR MODIFICATIONS OF THE BIOSPHERE EXCEPT AT THE RISK OF HIS OWN SURVIVAL. THUS, THE CONTINUED PRODUCTION OF PLANT MATERIALS, WHETHER WILD OR CULTIVATED, IS THE BASIS FOR THE NUTRITIONAL SUPPORT OF MAN AS WELL AS ALL OTHER ANIMALS.

THE CONTINUED FUNCTIONING OF GREEN PLANTS IS THE SOURCE OF ATMOSPHERIC OXYGEN ON WHICH MAN AND OTHER ORGANISMS DEPEND . THE CONTINUED FUNCTIONING OF THE DECOMPOSERS IS THE MEANS BY WHICH THE CHEMICALS IN HUMAN WASTES OR IN THE BODIES OF PLANTS AND ANIMALS ARE MADE AVAILABLE FOR FURTHER USE BY LIVING THINGS. A BREAK DOWN IN ANY OF THESE BIOSPHERIC SYSTEMS WOULD ENDANGER HUMAN SURVIVAL.

MANY SCIENTISTS BELIEVE THAT SPECIES DIVERSITY IS ESSENTIAL FOR THE PROPER FUNCTIONING OF COMMUNITIES AND FOR THE EMERGENCE OF COMMUNITY LEVEL PROPERTIES. JUST AS MANY DECODED DNA-ENCODED ENZYMES ARE NEEDED FOR A COMPLEX ORGANISM TO FUNCTION PROPERLY. SCIENTISTS BELIEVE THAT MANY KINDS OF SPECIES ARE NECESSARY TO MAINTAIN COMMUNITY STRUCTURE. BUT IS ANY DIVERSITY SUFFICIENT, OR ARE SPECIFIC MIXES OF SPECIES NECESSARY FOR THE COMMUNITIES AND ECOSYSTEMS TO FUNCTION ? THIS IS A VERY OLD QUESTION  IN ECOLOGY AND TWO  OPPOSING VIEWS  EXIST. ONE VIEW IS THAT A COMMUNITY  IS FORMED BY THE SPECIES THAT HAPPENED TO ARRIVE FIRST- THAT THE MIX OF SPECIES IN A COMMUNITY IS A MATTER OF CHANCE. THE VEGETATION OF AN AREA IS MAINLY  THE RESULTANT OF TWO FACTORS, THE FLUCTUATING  AND VARIABLE  ENVIRONMENT. ACCORDING TO  THE OPPOSING VIEW, IN A FAIRLY LIMITED AREA, ONLY A FRACTION  OF THE FORMS THAT COULD THEORETICALLY DO SO ACTUALLY FORM A COMMUNITY AT ANY ONE TIME. THE COMMUNITY IS REALLY AN ORGANIZED COMMUNITY IN THAT IT HAS A LIMITED MEMBERSHIP.

ARE THESE TWO VERY DIFFERENT VIEWS REALLY IRRECONCILABLE ? NOT NECESSARILY, IF THE COMMUNITY IS DEFINED AS THE SUM OF ALL THE PLANTS AND ANIMALS THAT GROW TOGETHER IN AN AREA, CERTAIN PATTERNS  CAN BE OBSERVED; AREAS WITH MORE THAN 1000 mm OF EVENLY DISTRIBUTED RAINFALL ALWAYS CONTAIN A WOODLAND; CONIFERS OCCUR IN AREAS OF EXTREMELY  LOW WINTER TEMPERATURES ; TREES IN WARM MOIST CLIMATE HAVE BROAD LEAVES; AND  SUCCULENT PLANTS ARE FOUND IN ARID CLIMATES. THE SAME IS TRUE FOR ANIMALS. THE MIX OF SPECIES ENCOUNTERED IN A  COMMUNITY IS NOT A RANDOM SAMPLE OF ALL PLANTS AND ANIMALS  IN THE WORLD.GREATER DIVERSITY IN PLANT COMMUNITY  WILL RESULT IN A GREATER DIVERSITY OF ANIMAL SPECIES. THE HEALTH AND REGENERATION  OF THE ECOSYSTEMS  GETS BETTER WITH SPECIES DIVERSITY.

IN A COMMUNITY  TWO TYPES OF PROCESSES ARE AT WORK AND NEITHER OF THEM IS DOMINANT. FIRST, THERE IS NATURAL SELECTION  SPECIES IN THE COMMUNITY ARE CONSTANTLY EVOLVING TO INCREASE THEIR ABILITY  TO WITHSTAND THE RIGOURS OF ENVIRONMENT. THIS PROCESS ACCOUNTS FOR THE COLD-HARDY SPECIES NEAR THE  POLES, FOR GRASS- EATING  RUMINANTS NEAR THE  SAVANNAS, AND FOR FRUIT-EATING BATS IN THE FORESTS. THE INDIVIDUAL THAT ESCAPES ITS PREDATORS AND IS  ABLE TO SURVIVE  OTHER ENVIRONMENTAL  CHALLENGES PASS ON THEIR CHARACTERISTICS IN THE COMMUNITY THAT WERE ONCE ADVANTAGEOUS CAN BECOME A BURDEN. DISEASE MIGHT BE INTRODUCED , SUCH AS DUTCHELM DISEASE FOR WHICH LOCAL SPECIES HAVE NO DEFENCE. HURRICANES, TORNADOES, FLOODS AND DROUGHTS ARE UNPREDICTABLE  AND THEIR FREQUENCY CHANGES WITH TIME . CHANCE ALSO PLAYS A ROLE IN DISPERSAL. FOR  EXAMPLE, A SPECIES MIGHT BE  ABSENT FROM A COMMUNITY PURELY BY CHANCE. THUS, BOTH NATURAL  SELECTION  AND CHANCE RESULT IN  THE STEADY COMING  AND GOING OF SPECIES THROUGH IMMIGRATION, EXTINCTION AND GENE MUTATION.

A LARGE NUMBER OF QUESTIONS EXIST REGARDING  THE ECOLOGICAL  ROLE  OF BIODIVERSITY IN COMMUNITIES. FOR EXAMPLE, CAN MORE AND MORE SPECIES BE PACKED INTO A COMMUNITY, OR ARE THERE UPPER AND LOWER LIMITS ? A RELATED QUESTION CONCERNS OPTIMAL LEVELS OF DIVERSITY AND THE FACTORS THAT CONTROL THEM. OTHER ISSUES INCLUDE THE ROLE OF  DIFFERENT INDIVIDUALS WITHIN A POPULATION, DIFFERENT POPULATIONS WITH A SPECIES AND SO ON.

IN A VARIABLE ENVIRONMENT, THE  EXISTENCE  OF INDIVIDUALS WITH DIFFERENT CHARACTERISTICS MAY INCREASE IN WAYS IN WHICH THE POPULATION CAN RESPOND TO CHANGE. FOR EXAMPLE, IF ALL PLANTS OF A SPECIES HAD SIMILAR WATER REQUIREMENTS, ALL OF THEM WOULD SUFFER WATER STRESS IN ANY YEAR THAT WAS DRIES THAN NORMAL; AND SUCH PERIODS WOULD RESULT IN SIGNIFICANTLY REDUCED SEED PRODUCTION ON THE OTHER HAND, IF THERE IS GENETIC VARIATION, SOME INDIVIDUALS MIGHT PERFORM ABOVE AVERAGE  EACH YEAR WITHIN CERTAIN  LIMITS OF ENVIRONMENTAL VARIATION. THEREFORE, SEED PRODUCTION WOULD BE SATISFACTORY IN BOTH WET AND DRY YEARS. MOREOVER, GENETICALLY ADAPTABLE ORGANISMS SHOULD SURVIVE IN MORE ENVIRONMENTS THAN THE GENETICALLY UNIFORM POPULATIONS. EXPERIENCE WITH CROPS SHOWS THAT HIGHLY PRODUCTIVE BUT GENETICALLY UNIFORM VARIETIES HAVE MORE  RESTRICTED ENVIRONMENTAL REQUIREMENTS THAN THE  LESS PRODUCTIVE BUT MORE VARIABLE VARIETIES. PLANTATIONS FORMED BY UNIFORM VARIETIES ARE MORE SUSCEPTIBLE TO DISEASE OUTBREAKS.

THUS WE SEE THAT VARIABILITY WITH A SPECIES SEEMS TO BE IMPORTANT FOR LONG TERM SURVIVAL. DOES THE SAME HOLD FOR A COMMUNITY, WHICH IS FORMED OF SPECIES THAT LIVE TOGETHER BUT DO NOT HAVE A COMMON GENE POOL? COMMUNITIES WITH HIGH SPECIES DIVERSITY MAY ALSO COPE WITH LONG TERM  ENVIRONMENTAL FLUCTUATIONS BETTER THAN THE COMMUNITIES  WITH SPECIES. HOWEVER, THE EVIDENCE IS CONTRADICTORY. TERRESTRIAL COMMUNITIES WITH FEW SPECIES. HOWEVER, THE EVIDENCE IS CONTRADICTORY. TERRESTRIAL COMMUNITIES IN THE CLIMATICALLY VARIABLE MID-LATITUDES ARE LESS DIVERSE THAN  TROPICAL  COMMUNITIES IS MORE UNIFORM ENVIRONMENTS. DEEP BENTHIC COMMUNITIES ARE AMONG THE MOST VARIABLE COMMUNITIES ANYWHERE EVEN THOUGH THEY EXIST IN POSSIBLY THE MOST UNIFORM ENVIRONMENT OF THE PLANT.

THE STEADY INCREASE IN HUMAN PRESSURE ON THE  EARTH'S SURFACE IS DRIVING ON EXTINCTION  SPASM THAT SEEMS LIKELY TO RIVAL OR SURPASS IN RATE FAR BEYOND NATURAL PRECEDENT. IN THE PERIOD SINCE 1600, 171 BIRD AND  115 MAMMAL SPECIES ALONE ARE  KNOWN  TO HAVE BECOME  EXTINCT THROUGH HUMAN ACTION. THESE FIGURES, FOR THE KNOWN  AND  LABELLED EXTINCTIONS OF THE KIND, DO NOT COUNT FOR THE SPECIES THAT MAY HAVE  OCCURRED UNNOTICED. IT IS ESTIMATED THAT ABOUT 1 PERCENT OF ALL SPECIES PRESENT IN 1600 HAVE  BECOME EXTINCT, HALF OF THEM SINCE 1881 CURRENT HUMAN ACTIVITY IS EXPECTED TO RESULT  IN THE LOSS  OF  GENETIC DIVERSITY WITHIN THE SPECIES AND A THREAT TO ITS SURVIVAL OF ITS GEOGRAPHICAL RANGES. MAN'S ACTIVITIES HAVE TRANSFORMED THE EARTH INTO A LESS HOSPITABLE PLACE FOR MANY LIVING ORGANISMS, THROUGH MORE INVITING FOR A FORTUNATE FEW.

HABITAT CHANGE  LIKE WISE AFFECTS THE DIVERSITY OF WILDLIFE  IN AN ECOSYSTEM. EVEN SMALL LANDSCAPE  TRANSFORMATION CAN OBLITERATE THE HOME OF AN ENDEMIC SPECIES. DRAINAGE OF WETLANDS; THE  PLOUGHING OF GRASSLANDS AND DEFORESTRATION   HAVE GREATLY REDUCED THE NUMBERS AND NARROWED THE RANGE , EVEN OF WIDELY  DISPERSED SPECIES. THE COUPLED EFFECT OF HABITAT LOSS AND HUNTING HAS GREATLY SHRUNK THE RANGE OF MANY SPECIES, AS A  RESULT DISRUPTING THE ECOLOGICAL  FUNCTIONING OF ECOSYSTEMS.POLLUTION, A  SPECIAL CASE OF HABITAT CHANGE  REPRESENTS AN ADDED FORM OF IMPACT ESPECIALLY  IN HIGHLY DEVELOPED AND INDUSTRIALIZED REGIONS.

RESEARCH SUGGESTS THAT A MORE  DIVERSE  ECOSYSTEM IS BETTER ABLE TO WITHSTAND ENVIRONMENTAL STRESS AND  CONSEQUENTLY IS MORE PRODUCTIVE . THE LOSS OF A SPECIES IS THUS LIKELY TO DECREASE THE ABILITY OF THE  SYSTEM TO MAINTAIN ITSELF OR TO RECOVER FROM DAMAGE OR DISTURBANCE. JUST LIKE A SPECIES WITH HIGH  GENETIC DIVERSITY, AN ECOSYSTEM WITH HIGH  BIODIVERSITY MAY HAVE A GREATER CHANCE OF ADAPTING TO ENVIRONMENTAL CHANGE. IN OTHER WORDS, THE MORE SPECIES COMPRISING AN ECOSYSTEM, THE MORE STABLE THE  ECOSYSTEM IS LIKELY TO BE . THE MECHANISMS UNDERLYING THESE EFFECTS ARE COMPLEX AND HOTLY CONTESTED. IN RECENT YEARS, HOWEVER, IT HAS  BECOME CLEAR THAT THERE ARE REAL ECOLOGICAL EFFECTS  OF BIODIVERSITY.

NATURE  CERTAINLY  HAS  SOME BUILT DEDUN DANCY, AND SOME DIVERSITY COULD BE  LOST WITHOUT BEING NOTICED. NEVERTHLESS, FEW DATA ARE AVAILABLE ON WHICH GENES OR SPECIES ARE PARTICULARLY IMPORTANT IN THE  FUNCTIONING OF ECOSYSTEMS, SO IT IS DIFFICULT TO ESTIMATE THE EXTENT TO  WHICH SOCIETY IS SUFFERING FROM THE LOW OF BIODIVERSITY. THE IMPACT OF  THE LOSS OF TOP PREDATORS MAY BE OBVIOUS ENOUGH, BUT THE ECOLOGICAL ROLES PLAYED IN MANY SPECIES OR POPULATIONS ARE STILL ONLY PARTLY KNOWN. DUE TO THIS UNCERTAINTY ABOUT THE ROLES OF DIFFERENT COMPONENTS IN  DETERMINING THE FUNCTIONING OF ECOSYSTEMS, THE WISEST COURSE IS TO APPLY PRECAUTIONARY PRINCIPLES AND VOID ACTIONS THAT NEEDLESSLY REDUCE BIOLOGICAL DIVERSITY.

ECOLOGICAL ROLE OF BIODIVERSITY IN SHORT

ALL SPECIES PROVIDE SOME KIND OF FUNCTION TO AN ECOSYSTEM. THEY CAN CAPTURE AND STORE ENERGY, PRODUCE AND DECOMPOSE ORGANIC MATERIAL HELPS IN CYCLING WATER AND NUTRIENTS THROUGHOUT THE ECOSYSTEM, CONTROLS EROSION AND PESTS FIXES ATMOSPHERIC GASES, AND ALSO PLAYS A PIVOTAL ROLE IN REGULATING THE CLIMATE. ECOSYSTEMS ALSO PROVIDE VARIOUS SUPPORTS OF PRODUCTION, SUCH AS, SOIL FERTILITY, POLLINATORS OF PLANTS, PREDATORS, DECOMPOSITION OF WASTES, AND SERVICES SUCH AS PURIFICATION OF THE AIR AND WATER, STABILIZATION AND MODERATION OF THE CLIMATE, DECREASE OF FLOODING, DROUGHT AND OTHER ENVIRONMENTAL DISASTERS.

BEFORE WE LOOK INTO THE ECOLOGICAL ROLE PLAYED BY BIODIVERSITY IN AN ECOSYSTEM AND HOW IT HOLDS A CRUCIAL POSITION IN MAN'S OWN SURVIVAL, WE WILL BRIEFLY EXAMINE THE STRUCTURE OF THE BIOTIC COMPONENTS OF AN ECOSYSTEM.

COMMUNITIES HAVE STRUCTURES AND PROPERTIES THAT ARE ORGANIZED, AND COORDINATED IN SUCH A MANNER THAT THE SMALLER COMPONENTS ARE INSEPARABLY LINKED WITH THE LARGER COMPONENTS IN A HIERARCHY WHERE EACH LEVEL IS FORMED OF COMPONENTS OF A LOWER LEVEL WHICH IN ITSELF BECOMES A CONSTITUENT OF STILL A HIGHER LEVEL. ECOLOGICAL HIERARCHY OR ECOLOGICAL LEVELS OF ORGANIZATION ARE THE HIERARCHICAL LEVELS OF ORGANIZATION CONNECTED WITH ECOLOGICAL GROUPING OF ORGANISMS. THERE ARE NO SHARP DEMARCATIONS IN THE FUNCTIONAL SENSE AMONGST VARIOUS LEVELS OF ECOLOGICAL HIERARCHY, AS THE SAME INDIVIDUAL IS A COMPONENT OF THE POPULATION, THE BIOLOGICAL COMMUNITY AS WELL AS THE ECOSYSTEM.


THE INDIVIDUAL ORGANISM IS THE BASIC UNIT OF ECOLOGICAL HIERARCHY AS IT CONTINUOUSLY EXCHANGES MATERIALS AND INFORMATION WITH ITS ENVIRONMENT. NEW INDIVIDUALS DEVELOP FROM PRE-EXISTING ONES, AND BY THIS PROCESS HEREDITARY CHARACTERISTICS ARE TRANSFERRED. NO INDIVIDUAL CAN SURVIVE INDEPENDENTLY. POPULATIONS CONSIST OF SIMILAR INDIVIDUALS THAT INHABIT A PARTICULAR GEOGRAPHICAL AREA OR SPACE. ECOTYPES COMPRISE A LOCAL POPULATION THAT IS GENETICALLY ADAPTED TO A PARTICULAR ENVIRONMENT. A BIOTIC COMMUNITY IS ESTABLISHED WITH AN ASSEMBLAGE OF POPULATIONS COMPRISING DIFFERENT SPECIES OF PLANTS ANIMALS, BACTERIA, FUNGI WHICH LIVE IN A PARTICULAR AREA THROUGH COMPETITION PREDATION AND MUTUALISM ETC. EACH BIOTIC COMMUNITY HAS ITS OWN PECULIAR COMPOSITION AND STRUCTURE, EXAMPLE POND COMMUNITY, MARSH COMMUNITY.


A BIOTIC COMMUNITY FORMS A DISTINCT ECOLOGICAL UNIT. SUCH A UNIT MAY BE  FLORA, FAUNA OR BOTH.


COMMUNITY UNITS MAY BE VERY SMALL, LIKE THE COMMUNITY OF INVERTEBRATE. SAND FUNGI IS  A DECAYING LOG. THE EXTENT OF A COMMUNITY IS LIMITED ONLY BY THE REQUIREMENT OF A MORE OR LESS UNIFORM SPECIES  COMPOSITION. COMMUNITIES MAY BE DISTINGUISHED AS MAJOR COMMUNITIES ARE THOSE WHICH, TOGETHER WITH THEIR HABITATS, FORM MORE OR LESS COMPLETE AND SELF SUSTAINING  UNITS OR ECOSYSTEMS, EXCEPT FOR THE SUSTAINING SOLAR ENERGY. MINOR COMMUNITIES ALSO CALLED SOCIETIES, ARE SECONDARY AGGREGATIONS WITHIN A MAJOR COMMUNITY AND ARE NOT, THEREFORE, COMPLETELY INDEPENDENT UNITS AS FAR AS  CIRCULATION  OF ENERGY IS CONCERNED. THE BIOTIC COMMUNITY ALONG WITH THEIR HABITATS, FORM MORE OR LESS COMPLETE AND SELF SUSTAINING UNITS OR ECOSYSTEMS, EXCEPT FOR THE SUSTAINING SOLAR ENERGY. MINOR COMMUNITIES  ALSO CALLED SOCIETIES, ARE SECONDARY AGGREGATIONS WITHIN A MAJOR COMMUNITY  AND  ARE NOT, THEREFORE, COMPLETELY  INDEPENDENT UNITS AS FAR AS  CIRCULATION  OF ENERGY IS CONCERNED. THE BIOTIC  COMMUNITY ALONG WITH ITS HABITAT, CALLED AN ECOSYSTEM, COMPRISES  UNITS OF VARIOUS SIZES AND CHARACTERISTICS, AND ARE LIMITED  TO DISTINCTIVE COMBINATIONS OF AIR, SOIL AND WATER. THESE FUNCTIONS ARE IMPORTANT  FOR ECOSYSTEMS  FUNCTION AND HUMAN SURVIVAL.


THE PHYSICAL ENVIRONMENT IS COMPOSED OF SUNLIGHT, ATMOSPHERE, WATER AND SOIL OF ROCK. ALL THESE PHYSICAL ELEMENTS AFFECT THE LIVING ORGANISMS, AND ALL ARE  IN TURN AFFECTED  BY THEM. PLANTS  FOR EXAMPLE, OBTAIN THEIR  ENERGY  FROM THE SUNLIGHT, THEIR BASIC FOOD FROM AIR AND WATER, SUPPLEMENTED BY CHEMICALS FROM THE SOIL ROCKS. PLANTS, HOWEVER, DIFFERENTIALLY REFLECT, REFRACT OR ABSORB VARIOUS WAVELENGTHS OF SUNLIGHT, AND THUS MODIFY IT. THROUGH THE USE OF CARBON DIOXIDE AND THE GIVING OFF OF OXYGEN AND WATER VAPOUR THEY MODIFY THE ATMOSPHERE. PLANTS ALSO REMOVE AND ADD VARIOUS CHEMICALS THROUGH WHICH SOIL IS MODIFIED OR ALTERED. ALL PLANTS AND ANIMALS EXIST AS A PART OF AN ECOSYSTEM. MAN, LIKE OTHER ANIMALS, IS DEPENDENT ON THE ECOSYSTEMS IN WHICH HE EXISTS DESPITE  HIS HIGH MOBILITY WHICH ENABLES  HIM TO MOVE FROM ONE PLACE TO ANOTHER OR TO EXTRACT PRODUCTS FROM ONE ECOSYSTEM AND EXPORT THEM TO ANOTHER. DESPITE THE TECHNOLOGY WHICH PERMITS HIM TO CREATE MAJOR MODIFICATIONS IN ANY ECOSYSTEM, HE HAS NO CONTROL OVER THE NATURAL FUNCTIONING AND SUSTENANCE  OF AN ECOSYSTEM. THUS, WE SEE THAT MAN TOO IS DEPENDENT LIKE OTHER ANIMALS ON THE ECOSYSTEM FOR HIS SURVIVAL AND FUNCTIONING.

IN AN ECOSYSTEM, THE PRODUCERS ARE USUALLY THE GREEN PLANTS THAT CONVERT SOLAR ENERGY  INTO CHEMICAL OR FOOD  ENERGY. CONSUMERS MAY BE HERBIVORES, CARNIVORES OR OMNIVORES THAT DEPENDS ON THE PRODUCERS DIRECTLY OR INDIRECTLY  FOR FOOD. DECOMPOSERS TAKE THE CHEMICALS BUILT UP BY THE GREEN PLANTS AND BREAK THEM INTO SIMPLER FORMS IN WHICH THEY CAN BE REUSED. 

THE SUSTENANCE OF THE ECOSYSTEM DEPENDS UPON THE DIVERSITY OF SPECIES IN AN ECOSYSTEM AND KEEPING IN BALANCE THE MINERALS BETWEEN THE BIOTIC  AND ABIOTIC COMPONENTS OF THE ECOSYSTEM.

AN ECOSYSTEM IS A SELF MAINTAINING  SYSTEM EXCEPT THAT IT DEPENDS ON THE  SUN AS ON EXTERNAL SOURCE OF ENERGY. THE LIVING COMPONENTS OF ECOSYSTEMS ARE PLANT AND ANIMAL SPECIES  INCLUDING  MICRO-ORGANISMS  THAT MAKE UP THE BIOTIC COMMUNITY. EACH SPECIES  IS ADAPTED TO A PARTICULAR  ROLE IN THE ECOSYSTEM KNOWN AS ITS ECOLOGICAL NICHE  EACH DEPENDS  FOR ITS EXISTENCE UPON THE PRESENCE OF A SUITABLE HABITAT, COMPRISING OTHER SPECIES AS WELL AS NECESSARY  COMPONENTS OF THE PHYSICAL ENVIRONMENT. THE FUNCTIONING OF THE ECOSYSTEM IS DEPENDENT  UPON THE PRESENCE OF A SUITABLE COMBINATION OF SPECIES EACH OF WHICH PERFORMS A SPECIALIZED TASK WITHIN THE TOTAL ECOSYSTEM.

ENERGY WILL PASS THROUGH AN ECOSYSTEM IN A ONE WAY PATH OF THE SOLAR ENERGY REACHING THE EARTH, ONLY A PORTION WILL BE STORED BY PLANTS, OFTEN LESS THAN ONE PERCENT OF THE TOTAL SOLAR  ENERGY  FALLING ON A VEGETATED AREA IS RETAINED  AS CHEMICAL ENERGY BY THE GREEN PLANTS OF THE TOTAL ENERGY THUS AVAILABLE IN PLANT TISSUES FOR CONSUMPTION BY ANIMALS, USUALLY LESS THAN TWENTY PERCENT  WILL BE STORED AS CHEMICAL ENERGY IN AN ANIMAL'S BODY TISSUES.

EVENTUALLY, AFTER SUPPORTING LIFE FOR A TIME, MOST OF THE ENERGY IS LOST TO THE ECOSYSTEM. SOME HOWEVER, IS STORED IN LONG -LIVED ORGANIC MATERIALS  SUCH AS TREE TRUNKS, OR IN DEAD ORGANIC MATERIALS  PRESERVED FROM DECOMPOSITION, WHICH EVENTUALLY FORM ORGANIC DEPOSITS OF ONE OR THE OTHER, INCLUDING PEAT, COAL, OIL AND NATURAL GAS OVER LONGER PERIODS OF TIME. BY CONTRAST, CHEMICAL NUTRIENTS FLOW THROUGH  THE ECOSYSTEM IN CIRCULAR  PATHWAYS, FROM SOIL TO PLANTS AND ANIMALS AND BACK TO SOIL, BEING REUSED OR RECYCLED AGAIN AND AGAIN.

             

MINERAL RESOURCE LIMITATION

GEOLOGISTS ARE APPREHENSIVE THAT MANY RESERVES OF MINERALS MAY NOT LAST FOR LONG AND MOST OF THEM WILL BE EXHAUSTED WITHIN 100 TO 200 YEARS. NEW POSSIBILITIES OF MINERAL RESERVES IN LAND AND BEYOND THE LAND, AS IN THE SEALED, ARE BEING EXPLORED WHICH MAY REDUCE, IF NOT TOTALLY REMOVE, THE FUTURISTIC FEARS OF EXHAUSTION OF THE RESOURCE.

CERTAIN MINERALS CANNOT BE REPLENISHED ONCE USED , WHILE THOSE THAT CAN BE RESOURCES. CONSERVATION IMPLIES EFFORTS TO UTILIZE MINERALS IN THE BEST POSSIBLE WAY, DEPENDING UPON THE INDUSTRIAL NEEDS AND CHANGING TECHNOLOGICAL REQUIREMENTS, SO THAT THE LIFE OF THE DEPOSITS IS INCREASED WITHOUT SACRIFICING ITS OWN NEEDS. CONSERVATION OF ENERGY MEANS CURTAILING UNNECESSARY OR WASTEFUL CONSUMPTION OF ENERGY AND MAKING THRIFTY USE OF USE OF ENERGY PRODUCING RESOURCES TO ENSURE THEIR STEADY SUPPLY FOR GENERATIONS.

BIOLOGICAL RESOURCE LIMITATION

FORESTS COVER ONE-THIRD OF THE WORLD'S LAND SURFACE OF WHICH ABOUT 50 PERCENT IS OCCUPIED BY TROPICAL FORESTS.ON A GLOBAL SCALE FORESTS REPRESENT HUGE MASSES OF PHOTOSYNTHETIC VEGETATION. THEY ARE RESPONSIBLE FOR RECYCLING THOUSANDS OF TONS OF CARBON DIOXIDE AND OXYGEN EVERYDAY. WITHOUT THE RAIN-FORESTS,OUR ATMOSPHERE WILL GRADUALLY DETERIORATE. EQUALLY IMPORTANT IS RAIN FORESTS RECYCLING OF WATER. OVER 75 PERCENT OF RAIN THAT FALLS ON THE FORESTS IS RETURNED TO THE ATMOSPHERE THROUGH EVAPORATION AND PLANT TRANSPIRATION. THIS WATER MAY TRAVEL HALF WAY  AROUND THE GLOBE BEFORE IT FALLS AS RAIN AGAIN. ANIMAL LIFE PLAYS AN IMPORTANT ROLE IN MAINTAINING THE FORESTS. DESTRUCTION OF THESE FORESTS MEANS EXTINCTION TO THE WILDLIFE , WHICH DIRECTLY OR INDIRECTLY  HELP IN CONTRIBUTING THE FOREST RESOURCES.

THE PRESENT AND THE FUTURE GENERATIONS WILL HAVE TO PAY A HEAVY PRICE FOR THE LOSS OF SPECIES , GENETIC DIVERSITY AND DEGRADATION OF HABITATS. BIOLOGICAL RESOURCES , WHICH COMPRISE OF THE PORTION OF BIODIVERSITY THAT IS OF ACTUAL OR POTENTIAL USE TO PEOPLE, PROVIDE THE BASIS FOR MOST HUMAN ENTERPRISES. THE SPECIES BEING LOST TODAY CONTAIN UNKNOWN FOOD, MEDICAL  AND INDUSTRIAL USES. DUE TO MISMANAGEMENT, THE BIOLOGICAL RESOURCES ARE LOSING THEIR CAPACITY TO SUPPORT THE HUMAN POPULATION DEPENDENT UPON THEM, AND THIS DEGRADATION IS INCREASING FURTHER COSTS THROUGH SOIL EROSION, SILTATION OF RESERVOIRS, LOCAL CLIMATE CHANGES, DESERTIFICATION AND LOSS OF PRODUCTIVITY.

HABITATS OF PLANTS AND ANIMALS PROVIDE FOOD AND SPACE FOR NORMAL GROWTH AND TERRITORIAL BEHAVIOUR, BREEDING AND MOVEMENT FOR ANIMALS. THERE IS CONSTANT INTERACTION BETWEEN ORGANISMS WITHIN THE HABITAT IN EXCHANGE OF ENERGY AND SHELTER . HUMANS ARE DESTROYING THIS HABITATS, THROUGH COMMERCIAL LOGGING, RECLAMATION OF WETLANDS AND POLLUTION. MIGRATORY BIRDS FROM THE SUB-POLAR REGIONS THAT SETTLE IN WETLAND AREAS DURING THE WINTER WILL SUFFER FROM DISTURBANCE IN THEIR MIGRATORY PATTERN AND BREEDING HABITS, IF WETLANDS DISAPPEAR. BUILDING OF DAMS ALONG RIVERS INUDATES ADJACENT LANDS, DESTROYING FORESTS AND KILLING ALL LIFE FORMS IN IT. IT ALSO UPSETS THE BREEDING PATTERNS OF FISH IN THE UPPER CATCHMENT AREA.

PROTECTED AREAS ARE INCREASINGLY SUBJECTED TO THREATS THAT EVEN THE BEST MANAGED AREAS CANNOT RESIST TO EXPLOITER. TO DATE A COMMERCIAL  LOGGER HAS FELT FREE TO EXPLOIT TIMBER STOCKS WITHOUT ANY REGARD OF WHAT HIS ACTIONS WOULD RESULT ON THE BIODIVERSITY. THE SAME APPLIES TO CATTLE RANCHERS, ROAD AND DAM BUILDERS AND OTHERS WHO EXPLOIT TROPICAL FORESTS MINDLESSLY.

POLICIES  THAT PROMOTE CONSERVATION MUST BE GIVEN SERIOUS ATTENTION BY THE GOVERNMENT AND COMMERCIAL DECISION MAKERS EVEN PARTIAL VALUATION OF THE BENEFITS OF COSERVING BIOLOGICAL RESOURCES CAN PROVIDE, AT LEAST , A LOWER LIMIT TO THE FULL RANGE OF BENEFITS THAT COSERVATION CONTRIBUTES TO NATIONAL ECONOMIC DEVELOPMENT.

MAN IS DAY BY DAY CONSUMING AND WASTING THE EARTH'S RESOURCES WITHOUT KEEPING IN MIND ITS LIMITATIONS. EARTH'S RESOURCES CAN ONLY BE STRETCHED TILL A CERTAIN POINT AFTER WHICH IT IS UNABLE TO REGENERATE OR REPRODUCE. UNLESS MAN USES THESE RESOURCES SUSTAINABLY AND CHECKS HIMSELF FROM OVER CONSUMPTION AND EXPLOITATION, HE WILL NOT BE ABLE TO SURVIVE FOR VERY LONG ON A PLANET STRIPPED OF ALL ITS RESOURCES.