Biodiversity – Function & type

Functions of Biodiversity

  • The word “biodiversity” is an abbreviated version of “biological diversity”.


The Convention on Biological Diversity defines biodiversity as: “the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species, and of ecosystems.”


Thus, Biodiversity refers to the variety of forms – the different plants, animals and micro-organisms. It also includes the genes they contain and the ecosystem they form. It deals essentially with dyna­mic processes and increases when new genetic variation is produced and decreases on the loss of genetic variation or species extinction.



There are three distinct levels of bio-diversity though all of them are components of a much intricate web.


  • Genetic Diversity:
  1. a) It refers to variation of genes within species.
  2. b) This variation can exist between different populations of the same species as well as between individuals within a population.
  3. c) Genetic diversity provides organisms and ecosystems with capacity to recuperate after change has occurred.
  4. d) Thus Genetic diversity is a level of biodiversity that refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary.
  5. e) Genetic diversity plays a great role in the adaptability and survival of a species. A species that has a large degree of genetic diversity among its individuals will have more variations from which to choose the most fitting allele.


  • Species Diversity:
  1. a) Species diversity is a measure of the diversity within an ecological community that incorporates both species richness (the number of species in a community) and the evenness of species’ abundance.


  1. b) Species diversity can be measured in terms of:
  2. Species richness – refers to the number of various species in a defined area.
  3. Species abundance – refers to the relative numbers among species. For example, the number of species of plants, animals and microorganisms may be more in an area than that recorded in another area.

iii. Taxonomic or phylogenetic diversity – refers to the genetic relationships between different groups of species.


  1. c) Species diversity is not evenly distributed across the globe. The overall richness of species is concentrated in equatorial regions and tends to decrease as one moves from equatorial to polar regions.


  1. d) In addition, biodiversity in land ecosystems generally decreases with increasing altitude. The other factors that influence biodiversity are amount of rainfall and nutrient level in soil. In marine ecosystems, species richness tends to be much higher in continental shelves.


  • Ecosystem Diversity:
  1. a) It refers to the presence of different types of ecosystems. For instance, the tropical south India with rich species diversity will have altogether different structure compared to the desert ecosystem which has far less number of plant and animal species.
  2. b) Likewise, the marine ecosystem although has many types of fishes, yet it differs from the freshwater ecosystem of rivers and lakes in terms of its characteristics. So such variations at ecosystem level are termed as ecosystem diversity.


  • Functional Diversity:
  1. a) Functional diversity refers to the diversity of ecological processes that maintain and are dependent upon the other components of diversity.
  2. b) Functional diversity includes the many ecological interactions among species e.g. competition, predation, parasitism, mutualism, etc. as well as ecological processes such as nutrient retention and recycling.
  3. c) It also includes the varying tempos and intensities of natural disturbances that many species and communities require if they are to persist.


Biodiversity supports ecosystem services including air quality, climate (e.g., CO2 sequestration), water purification, pollination, and prevention of erosion. Non-material benefits include spiritual and aesthetic values, knowledge systems and the value of education.


Biological Services Performed by Ecosystems


  • Protecting areas from soil erosion, floods and other harmful weather conditions:Vegetation cover helps to protect soils from erosion.  Woodlands and hedges provide useful windbreaks in farm areas, and the vegetation on mudflats and sand dunes can help protect coastal areas from erosion by the sea and wind.
  • Reducing the risk of local and global climate change:Ecosystems help maintain a healthy balance of gases in the atmosphere. Trees and other plants store carbon and help prevent the build-up of carbon dioxide in the atmosphere, reducing the risk of global warming.
  • Recycling nutrients:Bacteria and fungi play a crucial role in recycling nutrients in ecosystems.  Some plants play a crucial role in the fixation of nitrogen in the soil. Nitrogen fixation is the process of converting atmospheric nitrogen into ammonia.
  • Pollination and biological control:Some animals, especially birds, bats and insects perform important functions as pollinators of food plants such as vegetables and fruit, and are also often the natural enemies of weeds, pests and diseases that can harm crops.
  • Controlling pollutants:Plants like reeds act as natural filters, helping to remove waste from surface waters and many bacteria can help break down low level pollutants.
  • Monitoring the health of the environment:Some species can indicate a change in the environment. For example, the breeding failure among birds of prey can point to a buildup of pesticides in the system. Lichens such as those found growing on your school walls and on the trees may be sensitive indicators of levels of air pollution.


Economic and Social Value

  • Food:The provision of food is the most fundamental benefit that humans get from other life forms, and humans have always depended on animals and plants for meat, fruit, vegetables, nuts, and other natural products.
  • Medicines:Wild species have been used as sources of drugs for thousands of years. The medicinal potential of plants and animals is often considered a compelling reason to conserve biodiversity as some species are highly valued for their medicinal properties.
  • Commercial uses:Human societies have traditionally used plant and animal products like wool and fur for clothing, and wood for building construction and fuel. Other plant and animal products used in industry include feathers, skins, glues, rubber, oils, waxes, starches and dyes.
  • Cultural and aesthetic values:Historically, some species have played an important role in the folklore and traditions of many cultures. Species may also have heritage value as national symbols: for example, in Ireland, the three leafed clover (Trifolium) symbolises the nation’s identity and heritage. Biodiversity also has important recreational and aesthetic values.  Biodiversity also has educational and inspirational value.
  • Intrinsic values:For example, knowing that something exists is satisfying in itself, and the loss of a charismatic species, such as giant pandas and blue whales, represents a considerable loss of ‘existence value’. However, it is impossible to quantify and, unfortunately, many species, such as slugs and slime moulds, will never enjoy ‘existence value’. Many people also hold strong personal beliefs, feeling a great respect for the whole of nature and a responsibility to hand on to the next generation a world that is as rich in life as the world we live in today.



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