SPECIES DIVERSITY
VARIOUS UNDER WATER SPECIES OF PLANTS AND ANIMALS
THE FOLLOWING FACTORS DETERMINE THE DEGREE OF SPECIES DIVERSITY IN AN ECOSYSTEM OR COMMUNITY :
- HABITAT STRESS : SPECIES DIVERSITY IS LOW IN HABITATS UNDER ANY STRESS SUCH AS HARSH CLIMATE OR POLLUTION.
- GEOGRAPHICAL ISOLATION : SPECIES DIVERSITY IS LESS IN ISOLATED REGIONS LIKE AN ISLAND.IF A SPECIES IN AN ISLAND DISAPPEARS DUE TO RANDOM EVENTS, IT CANNOT BE EASILY REPLACED. ORGANISMS FROM THE MAINLAND HAVE DIFFICULTIES IN REACHING AND COLONIZING THE ISLAND.
- DOMINANCE BY ONE SPECIES : THE DOMINANT SPECIES CONSUMES A DISPROPORTIONATE SHARE OF THE RESOURCES. THIS DOES NOT ALLOW MANY SPECIES TO EVOLVE AND FLOURISH.
- EDGE EFFECT : THERE IS ALWAYS GREATER SPECIES DIVERSITY IN TRANSITION AREA, WHERE TWO OR MORE ECOSYSTEM OVERLAP.
- GEOLOGICAL HISTORY : OLD AND STABLE ECOSYSTEMS SUCH AS RAIN FORESTS THAT HAVE NOT EXPERIENCED MANY CHANGES HAVE HIGH SPECIES DIVERSITY. AN ECOSYSTEM LIKE THE ARCTIC HAS UNDERGONE MANY CHANGES AND THIS DOES NOT ALLOW ANY SPECIES TO ESTABLISH THEMSELVES.
SOME EXAMPLES OF LOW SPECIES DIVERSITY : -
*A SMALL ISOLATED ISLAND GENERALLY HAS LOW DIVERSITY OF SPECIES, SINCE FEW NEW SPECIES MIGRATE TO THE ISLAND.
A SMALL ISLAND NEAR THE COASTAL REGION OF INDIA
*THE POLAR REGION : THE FARTHER AWAY WE MOVE FROM THE EQUATOR TOWARDS EITHER POLE , THE LESS IS THE SPECIES DIVERSITY.
THE POLAR ICE CAPS
*A PATCH OF DESERT : THERE IS NORMALLY LITTLE SPECIES DIVERSITY TO BE SEEN IN A DESERT, ESPECIALLY DURING THE DAY. AT NIGHT, HOWEVER MANY DESERT SPECIES COME OUT OF THEIR HIDING PLACES.
THE THAR DESERT OF INDIA SUPPORT A VERY SMALL NUMBER OF LIFE
*AN APARTMENT COMPLEX IN A CITY, WITH THE GROUND COMPLETELY PAVED WITH CONCRETE.
SOME MAGNIFICENT EXAMPLES OF HIGH SPECIES DIVERSITY : -
*BOTANICAL GARDEN : IN A BOTANICAL GARDEN, WE SEE A WIDE VARIETY OF TREES, FLOWERING PLANTS, FLOWERING PLANTS, CACTI, AND SO ON.
BOTANICAL GARDEN SITUATED IN OOTY, INDIA
*TROPICAL RAIN FOREST : A TROPICAL RAIN-FOREST CONTAINS AN EXTRAORDINARY NUMBER OF DIFFERENT SPECIES OF PLANTS AND ANIMALS.
TROPICAL RAIN FORESTS OF INDIA ARE RICH IN BIODIVERSITY
*COASTAL ZONE : THE ZONE WHERE THE OCEAN MEETS LAND GENERALLY CONTAINS MANY DIFFERENT SPECIES . WE FIND IN THIS ZONE MARINE SPECIES, LAND SPECIES, ND OTHERS WHO LIVE ON LAND AND IN WATER.
MANGROVE FOREST OF SUNDERBAN DELTA
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GENETIC DIVERSITY
GENETIC DIVERSITY IS THE VARIETY IN THE GENETIC MAKE-UP AMONG INDIVIDUALS WITHIN A SPECIES. MANY PLANTS AND SOME ANIMAL SPECIES HAVE AS MANY AS 400,000 GENES. THESE CAN GIVE RISE TO ENORMOUS GENETIC VARIATION IN THE INDIVIDUALS IN THE SPECIES.
THE AMOUNT OF DIVERSITY AT THE GENETIC LEVEL IS IMPORTANT BECAUSE IT REPRESENTS THE RAW MATERIAL FOR EVOLUTION AND ADAPTATION. MORE GENETIC DIVERSITY IN A SPECIES OR POPULATION MEANS GREATER ABILITY FOR SOME OF THE INDIVIDUALS IN IT TO ADAPT TO CHANGES IN THE ENVIRONMENT.
LESS DIVERSITY LEADS TO UNIFORMITY, WHICH IS A PROBLEM IN THE LONG TERM. IT IS UNLIKELY THAT ANY INDIVIDUAL IN SUCH A POPULATION WOULD BE ABLE TO ADAPT TO CHANGING CONDITIONS.
EXAMPLE OF HIGH GENETIC DIVERSITY : -
*A VARIETY OF COLOURS, SIZES, AND TASTES AMONG BANANAS.
*DIFFERENT HAIR COLOURS AMONG HUMANS.
*THOUSANDS OF RICE VARIETIES WITH DIFFERENT COLOURS AND TASTES IN TRADITIONAL INDIAN AGRICULTURE.
*EXTRAORDINARY COLOURS AND PATTERNS AMONG BUTTERFLIES OF THE SAME SPECIES.
EXAMPLES OF LOW GENETIC DIVERSITY : -
*MODERN AGRICULTURE : PREVIOUSLY, THERE WERE THOUSANDS OF RICE VARITIES IN INDIA. THE GREEN REVOLUTION PROMOTED A SMALL NUMBER OF HIGH YIELDING VARIETIES. THUS, THE GENETIC DIVERSITY OF RICE IS NOW VERY LOW.
*THREATENED SPECIES : THE GIANT PANDA IN CHINA IS A THREATENED SPECIES. THERE ABOUT 1,000 PANDAS LEFT AND EVEN THESE ARE DISTRIBUTED OVER 20 SMALL POPULATIONS AS A RESULT THEIR GENETIC DIVERSITY IS VERY LOW.
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ECOSYSTEM DIVERSITY
ECOSYSTEM DIVERSITY IS THE VARIETY OF HABITATS FOUND IN AN AREA. IT IS THE VARIETY OF FORESTS, DESERTS, GRASSLANDS, AQUATIC ECOSYSTEM, ETC., THAT OCCUR IN THE AREA.
INDIA, FOR EXAMPLE,HAS HIGH ECOSYSTEM DIVERSITY. WE HAVE MOUNTAIN RANGES,LAKES, DESERTS, TEMPERATE FORESTS, TROPICAL RAIN FORESTS, ALPINE VEGETATION, BACKWATERS SNOW PEAKS, GRASSLANDS, RIVERS, CORAL REEFS, AND SO ON. GREEN LAND IN THE ARCTIC, ON THE OTHER HAND, HAS LITTLE ECOSYSTEM DIVERSITY. IT IS MOSTLY ICE AND SNOW.
SAVANNA GRASSLANDS IS THE BIGGEST GRASSLAND ECOSYSTEM IN THE BIOSPHERE.
SUNDARBAN FOREST OF INDIA IS
THE BIGGEST MANGROOVE FOREST OF THE WORLD AND A BIG ECOSYSTEM AS WELL AS IT SUPPORTS A LARGE VARIETY OF LIFE.
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