NATURE

Nature most commonly refers to the "natural environment", the Earth's environment or wilderness—including geology, forests, oceans, rivers,beaches, the atmosphere, life, and in general geographic areas that have not been substantially altered by humans, or which persist despite human intervention. This traditional concept of "nature" implies a distinction between natural and man-made, artificial elements of the Earth.

The term entered the English language in the 14th century and was derived from the Latin term natura - "that which has been born" - and may signify thenatural environment, natural areas unaffected by humans, the Universe, and forces that affect the world and space, such as astrophysics.

The term Natura was employed in Latin as a translation of the Greek word physis , which correlated plants, animals, and other features of the world as developing of their own accord. The concept of nature as a whole, the physical universe, is one of several expansions of the original notion; it began with certain core applications of the word by pre-Socratic philosophers, and has steadily gained currency ever since.

Earth (or, "the earth") is the only planetpresently known to support life, and its natural features are the subject of many fields of scientific research. Within thesolar system, it is third nearest to the sun; it is the largest terrestrial planetand the fifth largest overall. Its most prominent climatic features are its two large polar regions, two relatively narrowtemperate zones, and a wide equatorialtropical to subtropical region.Precipitation varies widely with location, from several metres of water per year to less than a millimetre. 71 percent of the Earth's surface is covered by salt-water oceans. The remainder consists of continents and islands, with most of the inhabited land in the Northern Hemisphere.

Earth has evolved through geological and biological processes that have left traces of the original conditions. The outer surface is divided into several gradually migrating tectonic plates, which have changed relatively quickly several times. The interior remains active, with a thick layer of molten mantle and an iron-filled core that generates a magnetic field.

The atmospheric conditions have been significantly altered from the original conditions by the presence of life-forms,which create an ecological balance that stabilizes the surface conditions. Despite the wide regional variations in climate by latitude and other geographic factors, the long-term average global climate is quite stable during interglacial periods, and variations of a degree or two of average global temperature have historically had major effects on the ecological balance, and on the actual geography of the Earth.