Biodiversity : Meaning, Importance Types - Practice Questions & MCQ

• Biodiversity is the term popularised by the sociobiologist Edward Wilson to describe the combined diversity at all the levels of biological organisation.
• Biological diversity or Biodiversity is defined as the variety and variability among the living organisms and the ecological complexes in which they occur.

Genetic diversity:

• A single species might show high diversity at the genetic level over its distributional range. 
• The genetic variation shown by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges might be in terms of the potency and concentration of the active chemical (reserpine) that the plant produces. 
• India has more than 50,000 genetically different strains of rice, and 1,000 varieties of mango.

Species diversity: 

• This is the diversity at the species level. 
• For example, the Western Ghats have a greater amphibian species diversity than the Eastern Ghats.

Ecological diversity: 

• At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity than a Scandinavian country like Norway.

• According to the IUCN (2004), the total number of plant and animal species described so far is slightly more than 1.5 million, but we have no clear idea of how many species are yet to be discovered and described. 
• For many taxonomic groups, species inventories are more complete in temperate than in tropical countries. 
• Robert May places the global species diversity at about 7 million.
• More than 70 percent of all the species recorded are animals, while plants (including algae, fungi, bryophytes, gymnosperms and angiosperms) comprise no more than 22 percent of the total. 
• Among animals, insects are the most species-rich taxonomic group, making up more than 70 per cent of the total. 
• That means, out of every 10 animals on this planet, 7 are insects. 
• The number of fungi species in the world is more than the combined total of the species of fishes, amphibians, reptiles and mammals. 
• Although India has only 2.4 percent of the world’s land area, its share of the global species diversity is an impressive 8.1 per cent. 
• That is what makes our country one of the 12 mega diversity countries of the world.
• Nearly 45,000 species of plants and twice as many animals have been recorded from India. 
• How many living species are actually there waiting to be discovered and named? If we accept May’s global estimates, only 22 percent of the total species have been recorded so far. 
• Applying this proportion to India’s diversity figures, we estimate that there are probably more than 1,00,000 plant species and more than 3,00, 000 animal species yet to be discovered and described.
                                         

• David Tilman’s long-term ecosystem experiments using outdoor plots provide some tentative answers to the significance of species diversity.
• Tilman found that plots with more species showed less year-to-year variation in total biomass. 
• He also showed that in his experiments, increased diversity contributed to higher productivity.
• The rich biodiversity is not only essential for ecosystem health but imperative for the very survival of the human race on this planet.
• The role of biodiversity can be explained by the rivet popper hypothesis used by Stanford ecologist Paul Ehrlich. 
  • In an airplane (ecosystem) all parts are joined together using thousands of rivets (species). 
  • If every passenger travelling in it starts popping a rivet to take home (causing a species to become extinct), it may not affect flight safety (proper functioning of the ecosystem) initially. 
  • But as more and more rivets are removed, the plane becomes dangerously weak over a period of time. 
  • Furthermore, which rivet is removed may also be critical. Loss of rivets on the wings (key species that drive major ecosystem functions) is obviously a more serious threat to flight safety than loss of a few rivets on the seats or windows inside the plane.