Tuesday, June 15, 2010

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.