The value of biodiversity is classified into direct and indirect values as shown in the below diagram.

Direct values

The direct value include food resources like grains, vegetables, fruits which are obtained from plant resources and meat, fish, egg, milk and milk products from animal resources. These also include other values like medicine, fuel, timber, fiber, wool, wax, resin, rubber, silk and decorative items.

The direct values are of two types (i) Consumptive use value and (ii) Productive use value.

Consumptive use value: These are the direct use values where the biodiversity products can be harvested and consumed directly. Example: Food, fuel and drugs. These goods are consumed locally and do no figure in national and international market.

(a)     Food:

(i) Plants: The most fundamental value of biological resources particularly plants is providing food. Basically three crops i.e. wheat, maize and rice constitute more than two third of the food requirement all over the world.

(ii) Fish: Through the development of aquaculture, techniques, fish and fish products have become the largest source of protein in the world.

(b)     Fuel: Since ages forests have provided wood which is used as a fuel. Moreover fossil fuels like coal, petroleum, natural gas are also product of biodiversity which are directly consumed by humans.

(c)     Drugs and medicines: The traditional medical practice like ayurveda utilizes plants or their extracts directly. In allopathy, the pharmaceutical industry is much more dependent on natural products. Many drugs are derived from plants like

(i)                   Quinine: The famous anti malaria drug is obtained from cinchona tree.

(ii)                 Penicillin: A famous antibiotic is derived from pencillium, a fungus.

(iii)                Tetracycline: It is obtained from bacterium.

(iv)                Recently vinblastin and vincristine, two anti cancer drugs have been obtained from catharanthus plant which has anti cancer alkaloids.

Productive use values: These are the direct use values where the product is commercially sold in national and international market. Many industries are dependent upon these values. Example- Textile, leather, silk, paper and pulp industry etc. Although there is an international ban on trade of products from endangered species like tusks of elephants, wool from sheep, fur of many animals etc. These are traded in market and fetch a booming business.

Indirect values

Biodiversity provides indirect benefits to human beings which support the existence of biological life and other benefits which are difficult to quantify. These include social and cultural values, ethical values, aesthetic values, option values and environment service values.

Social and cultural value: Many plants and animals are considered holy and sacred in India and are worshipped like Tulsi, peepal, cow, snake etc. In Indian society great cultural value is given to forest and as such tiger, peacock and lotus are named as the national animal, bird and flower respectively.

Ethical: These values are related to conservation of biodiversity where ethical issue of ‘all life forms must be preserved’ is laid down. There is an existence value which is attached to each species because biodiversity is valuable for the survival of human race. Moreover all species have a moral right to exist independent of our need for them.

Aesthetic value: There is a great aesthetic value which is attached to biodiversity. Natural landscapes at undisturbed places are a delight to watch and also provide opportunities for recreational activities like bird watching, photography etc. It promotes eco-tourism which further generates revenue by designing of zoological, botanical gardens, national parks, wild life conservation etc.

Option values: These values include the unexplored or unknown potentials of biodiversity.

Environment service values: The most important benefit of biodiversity is maintenance of environment services which includes

(i)                   Carbon dioxide fixation through photosynthesis.

(ii)                 Maintaining of essential nutrients by carbon (C),  oxygen (O), Nitrogen (N), Sulphur (S), Phosphorus (P) cycles.

(iii)                Maintaining water cycle and recharging of ground water.

(iv)                Soil formation and protection from erosion.

(v)                  Regulating climate by recycling moisture into the atmosphere.

(vi)                Detoxification and decomposition of waste.