page_title: Nature
section_title: Life
hierarchical_section_title: Nature / Life
caption_attribution_description: English: Female Mallard (Anas platyrhynchos) with ducklings Español: Un ánade real (Anas platyrhynchos) femenino con patitos.
context_page_description: Nature, in the broadest sense, is the natural, physical, or material world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are part of nature, human activity is often understood as a separate category from other natural phenomena.
  The word nature is derived from the Latin word natura, or "essential qualities, innate disposition", and in ancient times, literally meant "birth". In ancient philosophy, Natura is mostly used as the Latin translation of the Greek word physis, which originally related to the intrinsic characteristics that plants, animals, and other features of the world develop 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 φύσις by pre-Socratic philosophers, and has steadily gained currency ever since. During the advent of modern scientific method in the last several centuries, nature became the passive reality, organized and moved by divine laws.
context_section_description: Although there is no universal agreement on the definition of life, scientists generally accept that the biological manifestation of life is characterized by organization, metabolism, growth, adaptation, response to stimuli, and reproduction. Life may also be said to be simply the characteristic state of organisms.
  Properties common to terrestrial organisms (plants, animals, fungi, protists, archaea, and bacteria) are that they are cellular, carbon-and-water-based with complex organization, having a metabolism, a capacity to grow, respond to stimuli, and reproduce. An entity with these properties is generally considered life. However, not every definition of life considers all of these properties to be essential. Human-made analogs of life may also be considered to be life.
  The biosphere is the part of Earth's outer shell—including land, surface rocks, water, air and the atmosphere—within which life occurs, and which biotic processes in turn alter or transform. From the broadest geophysiological point of view, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere (rocks), hydrosphere (water), and atmosphere (air). The entire Earth contains over 75 billion tons (150 trillion pounds or about 6.8×10¹³ kilograms) of biomass (life), which lives within various environments within the biosphere.
  Over nine-tenths of the total biomass on Earth is plant life, on which animal life depends very heavily for its existence. More than 2 million species of plant and animal life have been identified to date, and estimates of the actual number of existing species range from several million to well over 50 million. The number of individual species of life is constantly in some degree of flux, with new species appearing and others ceasing to exist on a continual basis. The total number of species is in rapid decline.
caption: Female mallard and ducklings – reproduction is essential for continuing life
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