The resources which are taken from the environment and used directly without much modification are called natural resources like air, water, food, light and heat.
Tools and technology may be required to get the best possible use out of the natural resources.
Natural resources can further be categorized into groups based on their level of development and use, origin, stock and distribution.
Depending on their level of development and use, natural resources can be classified into two groups — actual resources and potential resources. Resources whose quantity and quality are known and are being used in present time are grouped as actual resources.
The resources existing in nature but are not being used at present are grouped as potential resources. In some cases, the level of technology available at present may not be advanced enough to easily use these resources. However, at a later stage, potential resources may be converted into actual resources. India is probably the 4th biggest wind power generator in the world.
Natural resources can also be classified on the basis of their origin. All organic resources and their products that are obtained from the biosphere are called biotic resources like plants, trees, animals, birds, fishes and other marine organisms.
Minerals like coal and petroleum are formed from decayed organic matter. Hence, these are also considered as biotic resources. All non-living resources like air, soil, water, rocks and minerals such as gold, silver and copper are examples of abiotic resources.
Natural resources can also be grouped on the basis of their stock i.e. on the amount of resources available for use. Resources that can be renewed and reproduced quickly are called renewable resources like the sun, air, wind, plants, trees, animals, water.
Of these, the sun, air and wind, are always available and their quantity is limitless and is not affected by use. These resources are known as flow resources. However, the stock of certain renewable resources can get depleted by use like crops, water, soil and forest resources.
Some resources like coal, petroleum and natural gas are limited. The formation of these resources is very slow and the period is more than the human life spans. Hence these natural resources are called non-renewable resources.
Natural resources can also be classified on the basis of their distribution in the world.
Resources like air, water and sun are found everywhere, hence are called ubiquitous resources. While natural resources like minerals, vegetation and wildlife are found only in certain places and so called as localized resources.