Natural resources (economically referred to as land or raw materials) occur naturally within environments that exist relatively undisturbed by mankind, in a natural form. A natural resource is often characterized by amounts of biodiversity existent in various ecosystems. Natural resources are derived from the environment. This is currently restricted to the environment of Earth yet the theoretical possibility remains of extracting them from outside the planet, such as the asteroid belt.^[1] Many of them are essential for our survival while others are used for satisfying our wants. Natural resources may be further classified in different ways.

Classification

On the basis of origin, resources may be divided into:

• Biotic - Biotic resources are obtained from the biosphere, such as forests and their products, animals, birds and their products, fish and other marine organisms. Mineral fuels such as coal and petroleum are also included in this category because they formed from decayed organic matter.
• Abiotic - Abiotic resources include non-living things. Examples include land, water, air and ores such as gold, iron, copper, silver etc.

Considering their stage of development, natural resources may be referred to in the following ways:

• Potential Resources - Potential resources are those that exist in a region and may be used in the future. For example, petroleum may exist in many parts of India, having sedimentary rocks but until the time it is actually drilled out and put into use, it remains a potential resource.
• Actual Resources are those that have been surveyed, their quantity and quality determined and are being used in present times. The development of an actual resource, such as wood processing depends upon the technology available and the cost involved. That part of the actual resource that can be developed profitably with available technology is called a reserve.

On the basis of status of development, they can be classified into potential resources,developed resources,stock and reserves.

With respect to renewability, natural resources can be categorized as follows:

• Renewable resources are ones that can be replenished or reproduced easily. Some of them, like sunlight, air, wind, etc., are continuously available and their quantity is not affected by human consumption. Many renewable resources can be depleted by human use, but may also be replenished, thus maintaining a flow. Some of these, like agricultural crops, take a short time for renewal; others, like water, take a comparatively longer time, while still others, like forests, take even longer.
• Non-renewable resources are formed over very long geological periods. Minerals and fossil fuels are included in this category. Since their rate of formation is extremely slow, they cannot be replenished once they get depleted. Of these, the metallic minerals can be re-used by recycling them.^[2] But coal and petroleum cannot be recycled.^[3]

On the basis of availability, natural resources can be categorised as follows:

• Inexhaustible natural resources- Those resources which are present in unlimited quantity in nature and are not likely to be exhausted easily by human activity are inexhaustible natural resources (sunlight, air etc.)
• Exhaustible natural resources- The amount of these resources are limited. They can be exhausted by human activity in the long run (coal, petroleum, natural gas, etc.)

Examples

Some examples of natural resources include the following:

• Air, wind and atmosphere
• Plants
• Animals
• Coal, fossil fuels, rock and mineral resources
• Forestry
• Range and pasture
• Soils
• Water, oceans, lakes, groundwater and rivers ^[4]

Management

Natural resource management is a discipline in the management of natural resources such as land, water, soil, plants and animals, with a particular focus on how management affects the quality of life for both present and future generations. Natural resource management is interrelated with the concept of sustainable development, a principle that forms a basis for land management and environmental governance throughout the world.

In contrast to the policy emphases of urban planning and the broader concept of environmental management, Natural resource management specifically focuses on a scientific and technical understanding of resources and ecology and the life-supporting capacity of those resources.

Depletion

In recent years, the depletion of natural resources and attempts to move to sustainable development have been a major focus of development agencies. This is a particular concern in rainforest regions, which hold most of the Earth's natural biodiversity - irreplaceable genetic natural capital. Conservation of natural resources is the major focus of natural capitalism, environmentalism, the ecology movement, and green politics. Some view this depletion as a major source of social unrest and conflicts in developing nations.

Mining, petroleum extraction, fishing, hunting, and forestry are generally considered natural-resource industries. Agriculture is considered a man-made resource. Theodore Roosevelt, a well-known conservationist and former United States president, was opposed to unregulated natural resource extraction. The term is defined by the United States Geological Survey as "The Nation's natural resources include its minerals, energy, land, water, and biota."^[5]

Protection

Conservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction.^[7][8] It is an interdisciplinary subject drawing on sciences, economics, and the practice of natural resource management.^{[9][10][11][12]} The term conservation biology was introduced as the title of a conference held University of California at San Diego in La Jolla, California in 1978 organized by biologists Bruce Wilcox and Michael Soulé.

Habitat conservation is a land management practice that seeks to conserve, protect and restore, habitat areas for wild plants and animals, especially conservation reliant species, and prevent their extinction, fragmentation or reduction in range.^[13]