Sociobiologist Edward Wilson popularised the term biodiversity. Biodiversity means the variety in the species of plants, animals, fungi and all the organisms present on the earth. It also covers the genetic information of the organisms. Biodiversity plays a significant role in the working of the different ecosystems. Some of its advantages include the following: 

• Humans derive several economic benefits from biodiversity like food, firewood, construction material and products of medicinal importance.
• Biodiversity plays a vital role in nature’s priceless services, e.g. oxygen provided by the Amazon forests.

Three Levels of Biodiversity 

Biodiversity is divided into three levels which are mentioned below. 

Genetic Diversity

Many species on earth are connected via genetic connections. The members of a species share genes. Genetic diversity is crucial for any population to adapt itself to the changing environment, and it is responsible for the biodiversity in the ecosystem.

Species with more diversity are less likely to become extinct. On the other hand, species with less diversity have lesser chances of survival because of unfavourable features like an inherited disease that can spread within the population. 

Species Diversity

The diversity at the level of species is referred to as species diversity. Species are the primary measure of biological diversity. The number of species present in a given region or ecosystem is known as species richness. Every region on the earth does not have the same number of species. For example, western ghats have more species than eastern ghats.

Ecological Diversity

Ecological diversity means the different types of ecosystems present in a geographical area. An ecosystem consists of various species which live and interact together via the flow of energy, nutrients etc. For example, India, with its mountains, deserts, rain forests, wetlands, mangroves, coral reefs, has a great ecosystem diversity compared to any other country in the world.

Number of Species on Earth and in India

Several records tell about the species discovered until now, but many species are yet to be discovered. According to IUCN(2004), more than 1.5 million total animal and plant species have been described so far. In terms of land area, India has 2.4 per cent of the world’s land area, but its share in the global biodiversity is around 8.1 per cent, and nearly 45000 species of plants and twice as many animals have been recorded from here making India one of the biodiversity hotspots of the world.

Pattern of Biodiversity

The variety of plants and animals is not consistent in every part of the earth, and it shows an uneven distribution. The biodiversity decreases from the equator toward the poles. For example, Columbia, which is located near the equator, has 1400 species of birds, and on the other hand, New York has just 105 species. The Amazon rainforest in South America is the largest biodiversity hotspot on earth.

Importance of Biodiversity

Biodiversity plays an important role in the functioning of the ecosystem, and it provides numerous benefits to humans like food, construction material, medicinal plants and oxygen.

Biodiversity also helps in regulating the climate, water quality, and diseases. Moreover, it has recreational and cultural benefits too.

Loss of biodiversity

The biodiversity of our planet is declining at a rapid pace. According to IUCN Red List (2004), 784 species have become extinct in the last 500 years, and some examples are the dodo (Mauritius), quagga (Africa), steller’s sea cow (Russia). Reasons for this biodiversity loss are:

• Habitat Loss: This is the main cause of the loss of biodiversity. Forests are the homes for the species, but now they are being destroyed rapidly for commercial purposes. Pollution also threatens the survival of many species.
• Over-Exploitation: Over-exploitation of natural resources by human beings has led to the loss of biodiversity, e.g. various species of fishes are over-harvested, and now their existence is endangered.
• Invasion of Alien Species: Sometimes, alien species are introduced with the native species, and some of them become invasive that pose a threat to the indigenous species.

Conservation of Biodiversity

There are two types of methods by which biodiversity can be protected:

• In-situ Conservation: When species are protected in their ecosystem or habitat or when the whole ecosystem is protected, then it is called In situ conservation. National parks, biosphere reserves and sanctuaries are examples of this type of conservation. In India, 14 biosphere reserves and 90 national parks are there.
• Ex-situ Conservation: In this type of conservation method, threatened species are taken out from their natural habitat and are placed in a special place where they can be taken care of and protected. To this end, several botanical gardens, zoological parks, and safari parks have been set up.

Conclusion  

Biodiversity refers to the diversity that exists in the biological organisation, and the term biodiversity was coined by Edward Wilson. India has about 45000 species of plants which are two as many as animals. Biodiversity generally is higher at the equator and decreases towards the poles. There are three levels of biodiversity, i.e. Genetic, species and ecological diversity. According to the IUCN Red List (2004), around 784 species have gone extinct in the last 500 years. The reasons for the consistent decline in the number of species are habitat loss, Over-exploitation of resources and alien species invasions. 

Biodiversity conservation can be of two types, i.e. in-situ and ex-situ. Under In situ conservation, species are given protection in their natural habitat and in ex situ conservation, the species are taken out of their habitat and placed in a special place.