BIODIVERSITY: DEFINITION AND ITS LEVELS, THREATS & CONSERVATIONS

 
The word biodiversity is a combination of two words: “biological and diversity” and refers to the variety of life on the Earth which includes a large number of living things that exist in a certain area (in the air, on land or in water). The area may be considered as small as a heap or as big as the whole planet. Hence, Biodiversity means “the existence of a large number of different kinds of animals and plants which make a balanced environment” and is called as biodiversity. Biodiversity deals with a large variety of flora and fauna on this earth. 
Ex: a wide variety of plants and animals are found in a part of the forest. The plant life range from a small herb to a large tree and the animal life varies from a tiny insect to a large mammal in addition to micro-organisms (algae, bacteria and fungi).
Biodiversity is usually considered at three different levels:
1. Genetic diversity means the variation of genes within the species.
Ex: In the human species, genetic variation between Indian and African and genetic variations within a population. (Ex: Within the Indian population) can be seen. In simple terms, genetic matter dictates whether the persons have blue or brown eyes, brown or black hair and is tall or short. Genetic diversity can be identified by using a variety of DNA-based and other techniques.
One estimate is that there are 1000 crores of different genes distributed across the world's biota though they do not all make an identical contribution to overall genetic diversity.
2. Species diversity means the richness of species in all ecosystems. It is measured on the basis of the number of species in a region. So far 1.75 million species have been described worldwide. Warmer areas tend to support more species than colder ones and wetter areas contain more species than drier ones. The topography and climate of the areas support and control the species of a region.
3. Ecosystem diversity means the study of differences between ecosystem types. Ecosystem diversity is difficult to measure since the boundaries of various sub-ecosystems overlap each other. Ex: for ecosystem diversity is the Godavari – Delta ecosystem which consists of a grassland ecosystem, river ecosystem, estuarine ecosystem, freshwater aquatic ecosystem, and marine water aquatic ecosystem.
 
THREATS TO BIODIVERSITY
Biodiversity is threatened by the following:
1.      Habitat Loss: Habitat is the place where a particular type of animal or plant is normally found and is the sum total of environmental factors, food cover and water that a given species need to survive and reproduce in a given area. Habitat loss may happen as quantitative loss and qualitative loss. The quantitative loss in terms of area. The qualitative loss was observed by determining the change of degradation in the structure, function and composition of the habitat. Ex: f an industry is releasing a chemical effluent into a water stream and poisoning the water, then it is qualitative loss. It is a habitat loss for aquatic organisms of that water stream.
2.      Pouching of wildlife: Illegal killing (pouching) of wildlife is occurring throughout the world for different reasons. Animals are killed for their meat, skin and organs as well as for other materials. Ex: the elephant is killed for ivory.
3.      Natural activities: Biodiversity is threatened by natural activities like floods, droughts, earthquakes, volcanoes, tsunamis, forest fires, desertification etc.
CONSERVATION OF BIODIVERSITY
Conservation of biodiversity can be achieved by 2 methods:
1.      In situ – conservation: It includes the conservation of plants and animals in the natural ecosystem or even manmade ecosystem. This type of conservation applied only to wild fauna and flora and not to domestic animals and plants. This conservation is achieved by protecting the population.
Ex:  National Parks, Sanctuaries etc
2.      Ex situ – conservation: This conservation includes the samples of genetic diversity mainly representing endangered species. This conservation can be achieved by establishing “gene banks”, which included resource centres.
Ex: Zoo, Botanical garden etc.