Nature
From Wikipedia, the free
encyclopedia
"Natural" and
"Natural World" redirect here. For other uses, see Nature (disambiguation) and Natural (disambiguation).
Nature, in the broadest sense, is
equivalent to the natural world, physical world, or material world. "Nature" refers
to the phenomena of the physical world, and
also to life in general. It ranges in
scale from the subatomic to the cosmic.
The word nature is derived from the Latin word natura, or "essential
qualities, innate disposition", and in ancient times, literally meant
"birth".[1] Natura was a Latin translation of
the Greek word physis (φύσις), which originally
related to the intrinsic characteristics that plants, animals, and other
features of the world develop of their own accord.[2][3] 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 bypre-Socratic philosophers, and has
steadily gained currency ever since. This usage was confirmed during the advent
of modern scientific method in the last several
centuries.[4][5]
Within the various uses of
the word today, "nature" often refers to geology and wildlife. Nature may
refer to the general realm of various types of living plants and animals, and
in some cases to the processes associated with inanimate objects – the way that
particular types of things exist and change of their own accord, such as the weather and geology of the Earth, and the matter and energy of which all these things
are composed. It is often taken to mean the "natural
environment" or wilderness–wild
animals, rocks, forest, beaches, and in general those things that have not been
substantially altered by human intervention, or which persist despite human
intervention. For example, manufactured objects and human interaction generally
are not considered part of nature, unless qualified as, for example,
"human nature" or "the whole of nature". This more
traditional concept of natural things which can still be found today implies a
distinction between the natural and the artificial, with the artificial being
understood as that which has been brought into being by a human consciousness or a human mind. Depending on the particular context, the
term "natural" might also be distinguished from the unnatural, the supernatural, orsynthetic.
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Contents
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1 Earth
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5 Life
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View of the Earth, taken in 1972 by theApollo 17 astronaut crew. This image is the
only photograph of its kind to date, showing a fully sunlit hemisphere of the
Earth.
Earth (or, "the earth")
is the only planet presently known to support
life, and its natural features are the subject of many fields of scientific
research. Within the solar system, it is
third closest 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 equatorial tropical to subtropical region.[6] 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. Theouter
surface is divided into several gradually migrating tectonic plates. The
interior remains active, with a thick layer of plastic 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,[7]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,[8] 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.[9][10]
[edit]Geology
Geology is the science and study of the solid and
liquid matter that constitutes the Earth. The field of geology encompasses the
study of the composition, structure, physical properties,
dynamics, and historyof Earth materials, and
the processes by which they are formed, moved, and changed. The field is a
major academic
discipline, and is also important for mineral and hydrocarbon extraction, knowledge about
and mitigation of natural hazards,
some Geotechnical engineering fields, and understanding past climates and environments.
The geology of an area
evolves through time as rock units are deposited and inserted and deformational
processes change their shapes and locations.
Rock units are first
emplaced either by deposition onto the surface or intrude
into the overlying rock. Deposition can occur when sediments settle onto the surface of
the Earth and later lithify intosedimentary rock, or
when as volcanic material such as volcanic ash or lava flows, blanket the surface.
Igneous intrusions such as batholiths, laccoliths, dikes, and sills, push upwards
into the overlying rock, and crystallize as they intrude.
After the initial sequence
of rocks has been deposited, the rock units can be deformed and/or metamorphosed.
Deformation typically occurs as a result of horizontal shortening, horizontal
extension, or side-to-side (strike-slip) motion.
These structural regimes broadly relate to convergent
boundaries, divergent
boundaries, and transform
boundaries, respectively, between tectonic plates.
[edit]Historical perspective
Plankton inhabit oceans, seas and
lakes, and have existed in various forms for at least 2 billion years.[11]
An animation showing the
movement of the continents from the separation of Pangaea until the present day.
Earth is estimated to have
formed 4.54 billion years ago from the solar nebula, along
with the Sun and other planets.[12] The moon formed roughly
20 million years later. Initially molten, the outer layer of the planet
cooled, resulting in the solid crust. Outgassing and volcanic activity produced the
primordial atmosphere. Condensing water vapor, most or
all of which came from icedelivered
by comets, produced the oceans and other water sources.[13] The highly energetic
chemistry is believed to have produced a self-replicating molecule around 4
billion years ago.[14]
Continents formed, then
broke up and reformed as the surface of Earth reshaped over hundreds of
millions of years, occasionally combining to make asupercontinent.
Roughly 750 million years ago, the earliest known supercontinent Rodinia, began to
break apart. The continents later recombined to form Pannotia which broke apart about
540 million years ago, then finally Pangaea, which broke
apart about 180 million years ago.[15]
There is significant
evidence that a severe glacial action during the Neoproterozoic era covered much of the
planet in a sheet of ice. This hypothesis has been termed the "Snowball Earth",
and it is of particular interest as it precedes the Cambrian
explosion in which multicellular life forms began to
proliferate about 530–540 million years ago.[16]
Since the Cambrian
explosion there have been five distinctly identifiable mass extinctions.[17] The last mass extinction
occurred some 65 million years ago, when a meteorite collision probably
triggered the extinction of the non-avian dinosaurs and other large reptiles,
but spared small animals such as mammals, which then resembled shrews. Over the past 65 million years,
mammalian life diversified.[18]
Several million years ago,
a species of small African ape gained the ability to stand
upright.[11] The subsequent advent of
human life, and the development of agriculture and further civilization allowed humans to affect
the Earth more rapidly than any previous life form, affecting both the nature
and quantity of other organisms as well as global climate. By comparison, the Great Oxygenation Event, produced by the
proliferation of algae during the Siderian period, required about
300 million years to culminate.
The present era is
classified as part of a mass extinction event,
the Holocene
extinction event, the fastest ever to have occurred.[19][20] Some, such as E. O. Wilson of Harvard
University, predict that human destruction of the biosphere could cause the extinction
of one-half of all species in the next 100 years.[21] The extent of the current
extinction event is still being researched, debated and calculated by biologists.[22]
Blue
light is scattered more than other wavelengths by
the gases in the atmosphere, giving
the Earth a blue halo when seen from space
The atmosphere of the Earth
serves as a key factor in sustaining the planetary ecosystem. The thin
layer of gases that envelops the Earth is
held in place by the planet's gravity. Dry air consists of 78% nitrogen, 21% oxygen, 1% argon and other inert gases, carbon
dioxide, etc.; but air also contains a variable amount ofwater vapor. The
atmospheric pressure declines steadily with altitude, and has a scale height of about 8 kilometres at
the Earth's surface: the height at which the atmospheric pressure has declined
by a factor of e (a mathematical constant
equal to 2.71...).[23][24] The ozone layer of the Earth's atmosphere
plays an important role in depleting the amount of ultraviolet (UV) radiation that reaches
the surface. As DNA is readily damaged by UV
light, this serves to protect life at the surface. The atmosphere also retains
heat during the night, thereby reducing the daily temperature extremes.
Terrestrial weather occurs
almost exclusively in the lower part of the atmosphere,
and serves as a convective system for redistributing heat. Ocean currents are another important
factor in determining climate, particularly the major underwater thermohaline circulation which distributes heat
energy from the equatorial oceans to the polar regions. These currents help to
moderate the differences in temperature between winter and summer
in the temperate zones. Also, without the redistributions of heat energy by the
ocean currents and atmosphere, the tropics would be much hotter, and the polar regions much colder.
Weather can have both
beneficial and harmful effects. Extremes in weather, such as tornadoes or hurricanes andcyclones, can expend
large amounts of energy along their paths, and produce devastation. Surface
vegetation has evolved a dependence on the seasonal variation of the weather,
and sudden changes lasting only a few years can have a dramatic effect, both on
the vegetation and on the animals which depend on its growth for their food.
The planetary climate is a
measure of the long-term trends in the weather. Various factors are known to influence the climate,
including ocean currents, surfacealbedo, greenhouse gases,
variations in the solar luminosity, and changes to the planet's orbit. Based on
historical records, the Earth is known to have undergone drastic climate
changes in the past, including ice ages.
The climate of a region
depends on a number of factors, especially latitude. A
latitudinal band of the surface with similar climatic attributes forms a
climate region. There are a number of such regions, ranging from the tropical climate at the equator to the polar climate in the northern and
southern extremes. Weather is also influenced by the seasons, which
result from the Earth's axis being tilted relative to its orbital plane. Thus, at any given time during the
summer or winter, one part of the planet is more directly exposed to the rays
of the sun.
This exposure alternates as the Earth revolves in its orbit. At any given time,
regardless of season, the northern and southern hemispheres experience
opposite seasons.
Weather is a chaotic system that is readily modified by
small changes to the environment,
so accurate weather forecasting is currently limited to
only a few days.[citation needed] Overall, two things are
currently happening worldwide: (1) temperature is increasing on the average;
and (2) regional climates have been undergoing noticeable changes.[25]
Water is a chemical
substance that is composed of hydrogen and oxygen and is vital for all known
forms of life.[26] In typical usage, water refers only to its liquid form or state, but the
substance also has a solidstate, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface.[27] On Earth, it is found
mostly in oceans and other large water bodies, with 1.6% of water below ground
inaquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid
water particles suspended in air), and precipitation.[28][29] Oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land
surface water such as rivers, lakes and ponds 0.6%. Additionally, a
minute amount of the Earth's water is contained within biological bodies and
manufactured products.
[edit]Oceans
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Earth's oceans
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Arctic
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Atlantic
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Indian
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Pacific
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Southern
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An ocean is a major body of saline water, and a
principal component of the hydrosphere. Approximately 71% of the Earth's surface (an area of some 361
million square kilometers) is covered by ocean, a continuous body of water that is customarily divided
into several principal oceans and smaller seas. More than half of this area is over
3,000 meters (9,800 ft) deep. Average oceanic salinity is around 35 parts
per thousand (ppt) (3.5%), and nearly all seawater has a
salinity in the range of 30 to 38 ppt. Though generally recognized as several
'separate' oceans, these waters comprise one global, interconnected body of
salt water often referred to as the World Ocean or global ocean.[30][31] This concept of a global
ocean as a continuous body of water with relatively free interchange among its
parts is of fundamental importance to oceanography.[32]
The major oceanic divisions
are defined in part by the continents, various archipelagos, and
other criteria: these divisions are (in descending order of size) the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, theSouthern Ocean and the Arctic Ocean.
Smaller regions of the oceans are called seas, gulfs, bays and other names. There are alsosalt lakes, which
are smaller bodies of landlocked saltwater that are not interconnected with the
World Ocean. Two notable examples of salt lakes are the Aral Sea and the Great Salt Lake.
[edit]Lakes
Lake Mapourika, New
Zealand
A lake (from Latin lacus) is a terrain feature (or physical feature), a
body of liquid on the surface of a world
that is localized to the bottom of basin (another type of landform
or terrain feature; that is, it is not global) and moves slowly if it moves at
all. On Earth, a body of water is considered a lake when it is inland, not part
of the ocean,
is larger and deeper than a pond, and is fed by a river.[33][34] The only world other than
Earth known to harbor lakes is Titan, Saturn's
largest moon, which has lakes of ethane, most likely mixed with methane. It is not
known if Titan's lakes are fed by rivers, though Titan's surface is carved by
numerous river beds. Natural lakes on Earth are generally found in mountainous
areas, rift zones, and
areas with ongoing or recent glaciation. Other
lakes are found in endorheic basinsor
along the courses of mature rivers. In some parts of the world, there are many
lakes because of chaotic drainage patterns left over from the last Ice Age. All lakes
are temporary over geologic time scales, as they will slowly fill in with
sediments or spill out of the basin containing them.
A pond is a body of standing water,
either natural or man-made, that is usually smaller than a lake. A wide variety of man-made bodies of
water are classified as ponds, including water gardens designed for aesthetic
ornamentation, fish ponds designed for commercial
fish breeding, and solar ponds designed to store thermal
energy. Ponds and lakes are distinguished from streams via current speed. While currents in
streams are easily observed, ponds and lakes possess thermally driven
microcurrents and moderate wind driven currents. These features distinguish a
pond from many other aquatic terrain features, such as stream pools and tide pools.
[edit]Rivers
A river is a natural watercourse,[35] usually freshwater, flowing
toward anocean, a lake, a sea or another river. In a few
cases, a river simply flows into the ground or dries up completely before
reaching another body of water. Small rivers may also be called by several
other names, including stream,
creek, brook, rivulet, and rill; there is no general rule that defines what can
be called a river. Many names for small rivers are specific to geographic
location; one example is Burn in Scotland and North-east
England. Sometimes a river is said to be larger than a creek,[36] but this is not always the
case, due to vagueness in the language.[37] A river is part of the hydrological
cycle. Water within a river is generally collected fromprecipitation through surface runoff, groundwater recharge, springs,
and the release of stored water in natural ice and snowpacks (i.e., from glaciers).
[edit]Streams
A stream is a flowing body
of water with a current, confined
within a bed and stream banks. In the United States a stream is classified as a
watercourse less than 60 feet (18 metres) wide. Streams are important as
conduits in thewater
cycle, instruments in groundwater
recharge, and they serve as corridors for fish and wildlife migration. The biological habitat in the immediate vicinity
of a stream is called a riparian zone. Given
the status of the ongoingHolocene
extinction, streams play an important corridor role in connecting fragmented habitats and thus in conservingbiodiversity. The
study of streams and waterways in general involves many branches of
inter-disciplinary natural science and engineering, including hydrology, fluvial geomorphology, aquatic ecology, fish biology, riparian ecologyand
others.
Loch Lomond in Scotland forms a
relatively isolated ecosystem. The fish community of this lake has remained
unchanged over a very long period of time.[38]
Lush
green Aravalli Mountain Range in the Desert country-Rajasthan, India. A wonder how such greenery can exist in
hot Rajasthan, a place well known for its Thar Desert
Ecosystems are composed of
a variety of abiotic and biotic components that function in
an interrelated way.[39] The structure and
composition is determined by various environmental factors that are
interrelated. Variations of these factors will initiate dynamic modifications
to the ecosystem. Some of the more important components are: soil, atmosphere, radiation from the sun, water, and living organisms.
Central to the ecosystem
concept is the idea that living organisms interact with every other
element in their localenvironment. Eugene Odum, a founder of ecology,
stated: "Any unit that includes all of the organisms (ie: the
"community") in a given area interacting with the physical environment
so that a flow of energy leads to clearly defined trophic structure, biotic
diversity, and material cycles (i.e.: exchange of materials between living and
nonliving parts) within the system is an ecosystem."[40] Within the ecosystem,
species are connected and dependent upon one another in thefood chain, and
exchange energy and matter between themselves as well
as with their environment.[41] The human ecosystem concept
is grounded in the deconstruction of the human/nature dichotomy and the premise that all
species are ecologically integrated with each other, as well as with the
abiotic constituents of their biotope.[citation needed]
A smaller unit of size is
called a microecosystem. For
example, a microsystem can be a stone and all the life under it. A macroecosystem might involve a whole ecoregion, with its drainage basin.[42]
[edit]Wilderness
Wilderness is generally defined as
areas that have not been significantly modified by human activity. The WILD Foundation goes into more detail,
defining wilderness as: "The most intact, undisturbed wild natural areas
left on our planet – those last truly wild places that humans do not control
and have not developed with roads, pipelines or other industrial
infrastructure." Wilderness areas can be found in preserves, estates,
farms, conservation preserves, ranches, national forests, national parks and even in urban areasalong
rivers, gulches or otherwise undeveloped areas. Wilderness areas and protected parks are considered important
for the survival of certain species, ecological
studies, conservation,
solitude, and recreation. Some
nature writers believe wilderness areas are vital for the human spirit and
creativity,[43] and some Ecologists consider wilderness areas
to be an integral part of the planet's self-sustaining natural ecosystem (the biosphere). They may
also preserve historic genetic traits and that they
provide habitat for wild flora and fauna that may be difficult to
recreate in zoos, arboretums or laboratories.
Although there is no
universal agreement on the definition of life, scientists generally accept that
the biological manifestation of life is characterized byorganization, metabolism, growth, adaptation, response
to stimuli and reproduction.[44] 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). Currently the entire
Earth contains over 75 billion tons (150trillion pounds or about 6.8×1013 kilograms) of biomass (life), which lives within
various environments within the biosphere.[45]
Over nine-tenths of the
total biomass on Earth is plant life, on which animal life depends very heavily
for its existence.[46] More than 2 million species
of plant and animal life have been identified to date,[47] and estimates of the actual
number of existing species range from several million to well over
50 million.[48][49][50] 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.[51][52] The total number of species
is presently in rapid decline.[53][54][55]
[edit]Evolution
An area of the Amazon Rainforest shared betweenColombia and Brazil. The tropical
rainforests of South America contain the largest diversity of species onEarth.[56][57]
Life is only known to exist
on the planet Earth.(cf Astrobiology) The origin of life is still a poorly
understood process, but it is thought to have occurred about 3.9 to
3.5 billion years ago during the hadean or archeaneons on a
primordial earth that had a substantially different environment than is found
at present.[58] These life forms possessed
the basic traits of self-replication and inheritable traits. Once life had
appeared, the process of evolution by natural selection resulted in the development
of ever-more diverse life forms.
Species that were unable to
adapt to the changing environment and competition from other life forms became
extinct. However, the fossil record retains evidence of
many of these older species. Current fossil and DNA evidence shows that all
existing species can trace a continual ancestry back to the first primitive
life forms.[58]
The advent of photosynthesis in very basic forms of
plant life worldwide allowed the sun's energy to be harvested to create
conditions allowing for more complex life.[citation needed] The resultant oxygen accumulated in the
atmosphere and gave rise to the ozone layer. The
incorporation of smaller cells within larger ones resulted in the development
of yet more complex cells called eukaryotes.[59] Cells within colonies
became increasingly specialized, resulting in true multicellular organisms.
With the ozone layer absorbing harmful ultraviolet radiation, life colonized the surface of
Earth.
[edit]Microbes
_Lorryia_formosa_2_edit.jpg)
The first form of life to
develop on the Earth were microbes, and they remained the only form of life on
the planet until about a billion years ago when multi-cellular organisms began
to appear.[60] Microorganisms are
single-celled organisms that are generally microscopic, and
smaller than the human eye can see. They include Bacteria, Fungi, Archaea and Protista.
These life forms are found
in almost every location on the Earth where there is liquid water, including
the interior of rocks within the planet.[61] Their reproduction is both
rapid and profuse. The combination of a high mutation rate and a horizontal gene transfer[62] ability makes them highly
adaptable, and able to survive in new environments, including outer space.[63] They form an essential part
of the planetary ecosystem. However some microorganisms are pathogenic and can post health risk to
other organisms.
[edit]Plants and animals
Originally Aristotle divided all living things
between plants, which generally do not move fast enough for humans to notice,
and animals. In Linnaeus' system,
these became the kingdoms Vegetabilia (later Plantae) and Animalia. Since then, it has become clear that
the Plantae as originally defined included several unrelated groups, and the fungi and several groups of algae were removed to new
kingdoms. However, these are still often considered plants in many contexts.
Bacterial life is sometimes included in flora,[64][65] and some classifications
use the term bacterial flora separately from plant flora.
Among the many ways of
classifying plants are by regional floras, which, depending on the purpose of
study, can also include fossil flora, remnants
of plant life from a previous era. People in many regions and countries take great pride in their individual arrays of characteristic flora, which can vary widely across the globe due to differences in climate and terrain.
of plant life from a previous era. People in many regions and countries take great pride in their individual arrays of characteristic flora, which can vary widely across the globe due to differences in climate and terrain.
Regional floras commonly
are divided into categories such as native floraand agricultural and garden
flora,
the lastly mentioned of which are intentionally grown and cultivated. Some
types of "native flora" actually have been introduced centuries ago
by people migrating from one region or continent to another, and become an
integral part of the native, or natural flora of the place to which they were
introduced. This is an example of how human interaction with nature can blur
the boundary of what is considered nature.
Another category of plant
has historically been carved out for weeds. Though the term has
fallen into disfavor among botanists as a formal way to
categorize "useless" plants, the informal use of the word
"weeds" to describe those plants that are deemed worthy of
elimination is illustrative of the general tendency of people and societies to
seek to alter or shape the course of nature. Similarly, animals are often
categorized in ways such as domestic, farm animals, wild animals,pests, etc.
according to their relationship to human life.
Animals as a category have several
characteristics that generally set them apart from other living things. Animals
are eukaryotic and usually multicellular(although
see Myxozoa),
which separates them from bacteria, archaea and most protists. They are heterotrophic,
generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants,
algae, and fungi by lacking cell walls.
With a few exceptions, most
notably the sponges (Phylum Porifera), animals
have bodies differentiated into separate tissues.[citation needed] These includemuscles, which are able to contract and
control locomotion, and a nervous system,
which sends and processes signals. There is also typically an internaldigestive chamber. The eukaryotic
cells possessed by all animals are surrounded by a characteristic extracellular
matrix composed of collagen and elasticglycoproteins. This
may be calcified to form structures like shells, bones, and spicules, a
framework upon which cells can move about and be reorganized during development
and maturation, and which supports the complex anatomy required for mobility.
Despite their natural
beauty, the secluded valleys along the Na Pali Coast inHawaii are heavily modified by
introducedinvasive
species such as She-oak.
Although humans currently
comprise only a minuscule proportion of the total living biomass on Earth, the
human effect on nature is disproportionately large. Because of the extent of
human influence, the boundaries between what humans regard as nature and
"made environments" is not clear cut except at the extremes. Even at
the extremes, the amount of natural environment that is free of discernible
human influence is presently diminishing at an increasingly rapid pace.
The development of
technology by the human race has allowed the greater exploitation of natural
resources and has helped to alleviate some of the risk from natural hazards. In
spite of this progress, however, the fate of humancivilization remains closely linked to
changes in the environment. There exists a highly complex feedback loop between
the use of advanced technology and changes to the environment that are only
slowly becoming understood.[66] Man-made threats to the
Earth's natural environment include pollution, deforestation, and
disasters such as oil spills. Humans have contributed to the extinction of many plants and animals.
Humans employ nature for
both leisure and economic activities. The acquisition of natural resources for
industrial use remains the primary component of the world's economic system.[citation needed] Some activities, such as hunting andfishing, are used
for both sustenance and leisure, often by different people. Agriculture was first adopted around
the9th
millennium BCE. Ranging from food production to energy, nature influences economic wealth.
Although early humans
gathered uncultivated plant materials for food and employed the medicinal
properties of vegetation for healing,[67] most modern human use of
plants is through agriculture. The clearance of large tracts of land for crop
growth has led to a significant reduction in the amount available of
forestation and wetlands, resulting in the loss of habitat for many plant and
animal species as well as increased erosion.[68]
[edit]Aesthetics and beauty
Beauty in nature has historically
been a prevalent theme in art and books, filling large sections of libraries
and bookstores. That nature has been depicted and celebrated by so much art, photography, poetry and other literature shows
the strength with which many people associate nature and beauty. Reasons why
this association exists, and what the association consists of, is studied by
the branch of philosophy called aesthetics. Beyond
certain basic characteristics that many philosophers agree about to explain
what is seen as beautiful, the opinions are virtually endless.[69] Nature and wildness have
been important subjects in various eras of world history. An early
tradition of landscape art began in China during the Tang Dynasty (618–907). The tradition of
representing nature as it is became one of the aims of Chinese painting and was a significant
influence in Asian art.
Although natural wonders
are celebrated in the Psalms and the Book of Job, wilderness portrayals in art became
more prevalent in the 1800s, especially in the works of the Romantic movement. British artists John Constable and J. M. W. Turnerturned
their attention to capturing the beauty of the natural world in their
paintings. Before that, paintings had been primarily of religious scenes or of
human beings. William
Wordsworth's poetry described the wonder of the natural world, which
had formerly been viewed as a threatening place. Increasingly the valuing of
nature became an aspect of Western culture.[70] This artistic movement also
coincided with the Transcendentalist movement in the Western world. A
common classical idea of beautiful art involves the word mimesis, the
imitation of nature. Also in the realm of ideas about beauty in nature is that
the perfect is implied through perfect mathematical forms and more generally bypatterns
in nature. As David Rothenburg writes, "The beautiful is the
root of science and the goal of art, the highest possibility that humanity can
ever hope to see".[71]:281
The first few hydrogen atom electron orbitals shown as cross-sections
with color-coded probability density
Some fields of science see nature as matter in
motion, obeying certain laws of nature which science seeks to understand. For
this reason the most fundamental science is generally understood to be "physics" –
the name for which is still recognizable as meaning that it is the study of
nature.
Matter is commonly defined
as the substance of which physical objects are composed. It constitutes the observable
universe. The visible components of the universe are now believed to
compose only 4.9 percent of the total mass. The remainder is believed to
consist of 26.8 percent cold dark matter and 68.3 percent dark energy.[72] The exact nature of these
components is still unknown and is currently under intensive investigation by
physicists.
The behavior of matter and
energy throughout the observable universe appears to follow well-defined physical laws. These
laws have been employed to produce cosmological models that successfully
explain the structure and the evolution of the universe we can observe. The
mathematical expressions of the laws of physics employ a set of twentyphysical constants[73] that appear to be static
across the observable universe.[74] The values of these
constants have been carefully measured, but the reason for their specific
values remains a mystery.
.jpg)
NGC 4414 is a spiral galaxy in the
constellation Coma Berenices about 56,000 light years in diameter and
approximately 60 million light years fromEarth
Outer space, also simply
called space, refers to the relatively
empty regions of the universe outside the atmospheres of celestial bodies. Outer space is used to
distinguish it fromairspace (and terrestrial
locations). There is no discrete boundary between the Earth's
atmosphere and space, as the atmosphere gradually
attenuates with increasing altitude. Outer space within the Solar System is called interplanetary
space, which passes over into interstellar
space at what is known as the heliopause.
Outer space is sparsely
filled with several dozen types oforganic molecules discovered to date by microwave spectroscopy, blackbody radiation left over from the big bang and the origin of the
universe, and cosmic rays, which
include ionized atomic nuclei and various subatomic
particles. There is also some gas, plasma and dust, and smallmeteors. Additionally, there are signs of
human life in outer space today, such as material left over from previous
manned and unmanned launches which are a potential hazard to spacecraft. Some
of this debris re-enters the atmosphere
periodically.
Although the planet Earth
is currently the only known body within the solar system to support life,
current evidence suggests that in the distant past the planetMars possessed bodies of liquid
water on the surface.[75] For a brief period in Mars'
history, it may have also been capable of forming life. At present though, most
of the water remaining on Mars is frozen. If life exists at all on Mars, it is
most likely to be located underground where liquid water can still exist.[76]
Conditions on the other
terrestrial planets, Mercury and Venus, appear to be too harsh to support life
as we know it.[citation needed] But it has been conjectured
that Europa, the
fourth-largest moon of Jupiter,
may possess a sub-surface ocean of liquid water and could potentially host
life.[77]
Recently, the team of Stéphane Udry have discovered a new
planet named Gliese 581 g, which
is an extrasolar planet orbiting the red dwarf star Gliese 581.[citation needed] Gliese 581 g appears to lie
in the habitable zone of space surrounding the star, and therefore could possibly host life as we know it.
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Media:
Organizations:
Science:
Philosophy:
·
Naturalism (philosophy): any of several philosophical
stances, typically those descended from Materialism and Pragmatism that do not distinguish the
supernatural from nature.[citation needed] This includes the methodological naturalism of natural science, which
makes the methodological assumption thatobservable events in nature are
explained only by natural causes, without assuming either the existence or
non-existence of the supernatural.
·
Balance
of nature (biological fallacy): A discredited concept
of natural equilibrium in predator:prey dynamics.
2. ^ A
useful though somewhat erratically presented account of the pre-Socratic use of
the concept of φύσις may be found in Naddaf, Gerard The Greek Concept
of Nature, SUNY Press, 2006. The word φύσις, while first used in connection
with a plant in Homer, occurs very early in Greek philosophy, and in several
senses. Generally, these senses match rather well the current senses in which
the English word nature is used, as confirmed by Guthrie,
W.K.C. Presocratic Tradition from Parmenides to Democritus (volume
2 of his History of Greek Philosophy), Cambridge UP, 1965.
3. ^ The
first known use of physis was by Homer in
reference to the intrinsic qualities of a plant: ὣς ἄρα φωνήσας πόρε φάρμακον ἀργεϊφόντης ἐκ γαίης ἐρύσας, καί μοι φύσιν αὐτοῦ ἔδειξε. (So saying,
Argeiphontes [=Hermes] gave me the herb, drawing it from the ground, and showed
me its nature.) Odyssey10.302-3 (ed. A.T. Murray). (The
word is dealt with thoroughly in Liddell and Scott's Greek
Lexicon.) For later but still very early Greek uses of the term,
see earlier note.
4. ^ Isaac
Newton's Philosophiae
Naturalis Principia Mathematica (1687), for example, is
translated "Mathematical Principles of Natural Philosophy", and
reflects the then-current use of the words "natural philosophy",
akin to "systematic study of nature"
5. ^ The
etymology of the word "physical" shows its use as a synonym for
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