Biodiversity found on Earth today consists of the many many distinct biological species, the merchandise of 4 billion years of evolution.
Biodiversity is that the sort of life on Earth, it includes all organisms, species, and populations; the genetic variation among these; and their complex assemblages of communities and ecosystems. It also refers to the interrelatedness of genes, species, and ecosystems and in turn, their interactions with the environment.
Levels of Biodiversity
Biodiversity is considered to exist at three levels: genetics, species, and ecosystems.
It is concerned with the variation in genes within a particular species.
*Genetic diversity allows species to adapt to changing environments.
*This diversity aims to make sure that some species sur vive drastic changes and thus keep it up desirable genes.
* The survival of individuals ensures the survival of the population.
* The genetic diversity gives us beautiful butterflies, roses, parakeets or coral during a myriad hues, shapes and sizes.
2) Species diversity:
* It refers to the variety of living organisms on earth.
* Species differ from each other , markedly in their genetic makeup, don’t inter-breed in nature,
* Closely-related species however have in common much of their hereditary characteristics. For in stance, about 98.4 per cent of the genes of humans and chimpanzees are an equivalent .
*It’s the ratio of 1 species population over total number of organisms across all species within the given biome.
* “Zero’ would be infinite diversity, and ‘one’ represents only one species present.
Measurement of Biodiversity
Biodiversity is measured by two major components:
1) Species richness, and
2) Species evenness.
1) Species richness
It is the measure of number of species found in a com munity
a) Alpha diversity
It refers to the range within a specific area or ecosystem, and is typically expressed by the amount of species (i.e., species richness) therein ecosystem.
b) Beta diversity
It is a comparison of diversity between ecosystems, usually measured as the change in amount of species between the ecosystems
c) Gamma diversity
It is a measure of the overall diversity for the different ecosystems within a region.
2) Species evenness
It measures the proportion of species at a given site, e.g. low evenness indicates that a few species dominate the site.
Services provided by Biodiversity:
Biodiversity provides variety of natural services for human beings:
* Protection of water resources
* Soils formation and protection • Nutrient storage and recycling
*Pollution breakdown and absorption
*Contribution to climate stability
*Maintenance of ecosystems
*Recovery from unpredictable events
(b) Biological services
*Medicinal resources and pharmaceutical drugs
*Diversity in genes, species and ecosystems.
Causes for Biodiversity Loss
Loss of biodiversity occurs when either a particular species is destroyed or the habitat essential for its survival is dam aged. The latter is more common as habitat destruction is inevitable fallout of development.
The extinction of species takes place once they are ex ploited for economic gain or hunted as sport or for food.
Extinction of species can also occur thanks to environmental reasons like ecological substitutions, biological factors and pathological causes which may be caused either naturally or man.
1) Natural causes
*Rivalry among species,
*Lack of pollination and diseases.
(b) Man-Made causes
* Habitat destruction
* Uncontrolled commercial exploitation
* Hunting & poaching
* Conversion of rich bio-diversity site for human settlement and industrial
* Extension of agriculture
*Filling up of wetlands
* Destruction of coastal areas
Conservation of biodiversity:
Modes of Conservation:
1) Ex-situ conservation: Conserving biodiversity outside the areas where they naturally occur is understood as ex- situ conservation.
*Here, animals are reared or plants are cultivated like zoological parks or botanical gardens. Reintroduc tion of an animal or plant into the habitat from where it’s become extinct is another sort of ex situ conservation.
2) In-situ conservation: Conserving the animals and plants in their natural habitats is understood as in-situ conservation. The established natural habitats are:
* National parks
* Biosphere reserves and
Constraints in biodiversity conservation *Low priority for conservation of living natural resources.
* Exploitation of living natural resources for monetary gain.
*Values and knowledge about the species and ecosystem are inadequate.
* Unplanned urbanization and uncontrolled industrialization.