NATURE AND WILDLIFE

A population is a summation of all the organisms of the same group or species, who live in the same geographical area, and have the capability of interbreeding.[1][2] In ecology the population of a certain species in a certain area is estimated using the Lincoln Index. The area that is used to define a sexual population is defined as the area where inter-breeding is potentially possible between any pair within the area. The probability of interbreeding is greater than the probability of cross-breeding with individuals from other areas. Under normal conditions, breeding is substantially more common within the area than across the border.[3]
In sociology, population refers to a collection of human beings. Demography is a social science which entails the statistical study of human populations. This article refers mainly to human population.
]Population genetics[edit]

In population genetics a sexual population is a set of organisms in which any pair of members can breed together. This means that they can regularly exchange gametes to produce normally-fertile offspring, and such a breeding group is also known therefore as a gamodeme. This also implies that all members belong to the same of species, such as humans.[4] .If the gamodeme is very large (theoretically, approaching infinity), and all gene alleles are uniformly distributed by the gametes within it, the gamodeme is said to be panmictic. Under this state, allele (gamete) frequencies can be converted to genotype (zygote) frequencies by expanding an appropriate quadratic equation, as shown by Sir Ronald Fisher in his establishment of quantitative genetics.[5] Unfortunately, this seldom occurs in nature : localisation of gamete exchange - through dispersal limitations, or preferential mating, or cataclysm, or other cause - may lead to small actual gamodemes which exchange gametes reasonably uniformly within themselves, but are virtually separated from their neighbouring gamodemes. However, there may be low frequencies of exchange with these neighbours. This may be viewed as the breaking up of a large sexual population(panmictic)into smaller overlapping sexual populations. This failure of panmixia leads to two important changes in overall population structure: (1).the component gamodemes vary (through gamete sampling) in their allele frequencies when compared with each other and with the theoretical panmictic original (this is known as dispersion, and its details can be estimated using expansion of an appropriate binomial equation); and (2). the level of homozygosity rises in the entire collection of gamodemes. The overall rise in homozygosity is quantified by the inbreeding coefficient (f or φ). Note that all homozygotes are increased in frequency - both the deleterious and the desirable! The mean phenotype of the gamodemes collection is lower than that of the panmictic "original" - which is known as inbreeding depression. It is most important to note, however, that some dispersion lines will be superior to the panmictic original, while some will be about the same, and some will be inferior. The probabilities of each can be estimated from those binomial equations. In plant and animal breeding, procedures have been developed which deliberately utilise the effects of dispersion (such as line breeding, pure-line breeding, back-crossing). It can be shown that dispersion-assisted selection leads to the greatest genetic advance (ΔG = change in the phenotypic mean), and is much more powerful than selection acting without attendant dispersion. This is so for both allogamous (random fertilization)[6] and autogamous (self-fertilization) gamodemes[7]
World human population[edit]

Main article: World population
As of today's date, the world population is estimated by the United States Census Bureau to be 7.09 billion.[8] The US Census Bureau estimates the 7 billion number was surpassed on 12 March 2012. According to a separate estimate by the United Nations, Earth’s population exceeded seven billion in October 2011, a milestone that offers unprecedented challenges and opportunities to all of humanity, according to UNFPA, the United Nations Population Fund.[9]
According to papers published by the United States Census Bureau, the world population hit 6.5 billion on 24 February 2006. The United Nations Population Fund designated 12 October 1999 as the approximate day on which world population reached 6 billion. This was about 12 years after world population reached 5 billion in 1987, and 6 years after world population reached 5.5 billion in 1993. The population of some[which?] countries, such as Nigeria, is not even known to the nearest million,[10] so there is a considerable margin of error in such estimates.[11]
Researcher, Carl Haub, calculated that a total of over 100 billion people have probably been born in the last 2000 years.[12]
Predicted growth and decline[edit]


Time taken for each billion people to be added to the world's population (including future estimates). See also alt. chart
Main article: Population growth
Population growth increased significantly as the Industrial Revolution gathered pace from 1700 onwards.[13] The last 50 years have seen a yet more rapid increase in the rate of population growth[13] due to medical advances and substantial increases in agricultural productivity, particularly beginning in the 1960s,[14] made by the Green Revolution.[15] In 2007 the United Nations Population Division projected that the world's population will likely surpass 10 billion in 2055.[16]
In the future, the world's population is expected to peak,[17] after which it will decline due to economic reasons, health concerns, land exhaustion and environmental hazards. According to one report, it is very likely that the world's population will stop growing before the end of the 21st century. Further, there is some likelihood that population will actually decline before 2100.[18] Population has already declined in the last decade or two in Eastern Europe, the Baltics and in the Commonwealth of Independent States.[19]
The population pattern of less-developed regions of the world in recent years has been marked by gradually declining birth rates. These followed an earlier sharp reduction in death rates.[20] This transition from high birth and death rates to low birth and death rates is often referred to as the demographic transition.[20]
Control[edit]
Main article: Human population control
Human population control is the practice of artificially altering the rate of growth of a human population. Historically, human population control has been implemented by limiting the population's birth rate, usually by government mandate, and has been undertaken as a response to factors including high or increasing levels of poverty, environmental concerns, religious reasons, and overpopulation. While population control can involve measures that improve people's lives by giving them greater control of their reproduction, many programs have exposed them to exploitation.
Worldwide, the population control movement was active throughout the 1960s and 1970s, driving many reproductive health and family planning programs. In the 1980s, tension grew between population control advocates and women's health activists who advanced women's reproductive rights as part of a human rights-based approach.[21] Growing opposition to the narrow population control focus led to a significant change in population control policies in the early 1990s.[22]

Water is a chemical compound with the chemical formula H
2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at standard ambient temperature and pressure, but it often co-exists on Earth with its solid state, ice, and gaseous state (water vapor or steam). Water also exists in a liquid crystal state near hydrophilic surfaces.[1][2]

Water covers 71% of the Earth's surface,[3] and is vital for all known forms of life.[4] On Earth, 96.5% of the planet's water is found in oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water bodies, and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation.[5][6] Only 2.5% of the Earth's water is freshwater, and 98.8% of that water is in ice and groundwater. Less than 0.3% of all freshwater is in rivers, lakes, and the atmosphere, and an even smaller amount of the Earth's freshwater (0.003%) is contained within biological bodies and manufactured products.[5]

Water on Earth moves continually through the water cycle of evaporation and transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea. Evaporation and transpiration contribute to the precipitation over land.

Safe drinking water is essential to humans and other lifeforms even though it provides no calories or organic nutrients. Access to safe drinking water has improved over the last decades in almost every part of the world, but approximately one billion people still lack access to safe water and over 2.5 billion lack access to adequate sanitation.[7] There is a clear correlation between access to safe water and GDP per capita.[8] However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability.[9] A recent report (November 2009) suggests that by 2030, in some developing regions of the world, water demand will exceed supply by 50%.[10] Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. Approximately 70% of the fresh water used by humans goes to agriculture.[11]
Chemical and physical properties

Main articles: Properties of water, Water (data page), and Water model


Model of hydrogen bonds (1) between molecules of water


Impact from a water drop causes an upward "rebound" jet surrounded by circular capillary waves.


Snowflakes by Wilson Bentley, 1902


Dew drops adhering to a spider web


Capillary action of water compared to mercury
Water is the chemical substance with chemical formula H
2O: one molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom.

Water appears in nature in all three common states of matter (solid, liquid, and gas) and may take many different forms on Earth: water vapor and clouds in the sky, seawater in the oceans, icebergs in the polar oceans, glaciers and rivers in the mountains, and the liquid in aquifers in the ground.

The major chemical and physical properties of water are:

Water is a liquid at standard temperature and pressure. It is tasteless and odorless. The intrinsic colour of water and ice is a very slight blue hue, although both appear colorless in small quantities. Water vapour is essentially invisible as a gas.[12]
Water is transparent in the visible electromagnetic spectrum. Thus aquatic plants can live in water because sunlight can reach them. Infrared light is strongly absorbed by the hydrogen-oxygen or OH bonds.
Since the water molecule is not linear and the oxygen atom has a higher electronegativity than hydrogen atoms, it carries a slight negative charge, whereas the hydrogen atoms are slightly positive. As a result, water is a polar molecule with an electrical dipole moment. Water also can form an unusually large number of intermolecular hydrogen bonds (four) for a molecule of its size. These factors lead to strong attractive forces between molecules of water, giving rise to water's high surface tension[13] and capillary forces. The capillary action refers to the tendency of water to move up a narrow tube against the force of gravity. This property is relied upon by all vascular plants, such as trees.[14]
Water is a good polar solvent and is often referred to as the universal solvent. Substances that dissolve in water, e.g., salts, sugars, acids, alkalis, and some gases – especially oxygen, carbon dioxide (carbonation) are known as hydrophilic (water-loving) substances, while those that are immiscible with water (e.g., fats and oils), are known as hydrophobic (water-fearing) substances.
Most of the major components in cells (proteins, DNA and polysaccharides) are also dissolved in water.
Pure water has a low electrical conductivity, but this increases with the dissolution of a small amount of ionic material such as sodium chloride.
The boiling point of water (and all other liquids) is dependent on the barometric pressure. For example, on the top of Mt. Everest water boils at 68 °C (154 °F), compared to 100 °C (212 °F) at sea level. Conversely, water deep in the ocean near geothermal vents can reach temperatures of hundreds of degrees and remain liquid.
At 4181.3 J/(kg·K), water has a high specific heat capacity, as well as a high heat of vaporization (40.65 kJ·mol−1), both of which are a result of the extensive hydrogen bonding between its molecules. These two unusual properties allow water to moderate Earth's climate by buffering large fluctuations in temperature.
The maximum density of water occurs at 3.98 °C (39.16 °F).[15] It has the anomalous property of becoming less dense, not more, when it is cooled to its solid form, ice. During freezing, the 'open structure' of ice is gradually broken and molecules enter cavities in ice-like structure of low temperature water. There are two competing effects: 1) Increasing volume of normal liquid and 2) Decrease overall volume of the liquid. Between 0 and 3.98 °C, the second effect will cancel off the first effect so the net effect is shrinkage of volume with increasing temperature.[16] It expands to occupy 9% greater volume in this solid state, which accounts for the fact of ice floating on liquid water, as in icebergs.
The density of liquid water is 1,000 kg/m3 (62.43 lb/cu ft) at 4 °C. Ice has a density of 917 kg/m3 (57.25 lb/cu ft).


ADR label for transporting goods dangerously reactive with water
Water is miscible with many liquids, such as ethanol, in all proportions, forming a single homogeneous liquid. On the other hand, water and most oils are immiscible, usually forming layers according to increasing density from the top. As a gas, water vapor is completely miscible with air.
Water forms an azeotrope with many other solvents.
Water can be split by electrolysis into hydrogen and oxygen.
As an oxide of hydrogen, water is formed when hydrogen or hydrogen-containing compounds burn or react with oxygen or oxygen-containing compounds. Water is not a fuel, it is an end-product of the combustion of hydrogen. The energy required to split water into hydrogen and oxygen by electrolysis or any other means is greater than the energy that can be collected when the hydrogen and oxygen recombine.[17]
Elements which are more electropositive than hydrogen such as lithium, sodium, calcium, potassium and caesium displace hydrogen from water, forming hydroxides. Being a flammable gas, the hydrogen given off is dangerous and the reaction of water with the more electropositive of these elements may be violently explosive.
Taste and odor

Water can dissolve many different substances, giving it varying tastes and odors. Humans and other animals have developed senses that enable them to evaluate the potability of water by avoiding water that is too salty or putrid. The taste of spring water and mineral water, often advertised in marketing of consumer products, derives from the minerals dissolved in it. However, pure H2O is tasteless and odorless. The advertised purity of spring and mineral water refers to absence of toxins, pollutants and microbes, not the absence of naturally occurring minerals.

Distribution in nature

In the universe
Much of the universe's water is produced as a byproduct of star formation. When stars are born, their birth is accompanied by a strong outward wind of gas and dust. When this outflow of material eventually impacts the surrounding gas, the shock waves that are created compress and heat the gas. The water observed is quickly produced in this warm dense gas.[18]

On 22 July 2011 a report described the discovery of a gigantic cloud of water vapor containing "140 trillion times more water than all of Earth's oceans combined" around a quasar located 12 billion light years from Earth. According to the researchers, the "discovery shows that water has been prevalent in the universe for nearly its entire existence".[19][20]

Water has been detected in interstellar clouds within our galaxy, the Milky Way. Water probably exists in abundance in other galaxies, too, because its components, hydrogen and oxygen, are among the most abundant elements in the universe. Interstellar clouds eventually condense into solar nebulae and solar systems such as ours.

Water vapor is present in

Atmosphere of Mercury: 3.4%, and large amounts of water in Mercury's exosphere[21]
Atmosphere of Venus: 0.002%
Earth's atmosphere: ~0.40% over full atmosphere, typically 1–4% at surface
Atmosphere of Mars: 0.03%
Atmosphere of Jupiter: 0.0004%
Atmosphere of Saturn – in ices only
Enceladus (moon of Saturn): 91%
exoplanets known as HD 189733 b[22] and HD 209458 b.[23]
Liquid water is present on

Earth: 71% of surface
Europa: 100 km deep subsurface ocean
Strong evidence suggests that liquid water is present just under the surface of Saturn's moon Enceladus.

Water ice is present on

Earth – mainly as ice sheets
polar ice caps on Mars
Moon
Titan
Europa
Saturn's rings[24]
Enceladus
Pluto and Charon[24]
Comets and comet source populations (Kuiper belt and Oort cloud objects).
Recent evidence points to the existence of water ice at the poles of Mercury.[25] Water ice may also be present on Ceres and Tethys. Water and other volatiles probably comprise much of the internal structures of Uranus and Neptune and the water in the deeper layers may be in the form of ionic water in which the molecules break down into a soup of hydrogen and oxygen ions, and deeper down as superionic water in which the oxygen crystallises but the hydrogen ions float around freely within the oxygen lattice.[26]

Some of the Moon's minerals contain water molecules. For instance, in 2008 a laboratory device which ejects and identifies particles found small amounts of the compound in the inside of volcanic rock brought from Moon to Earth by the Apollo 15 crew in 1971.[27] NASA reported the detection of water molecules by NASA's Moon Mineralogy Mapper aboard the Indian Space Research Organization's Chandrayaan-1 spacecraft in September 2009.[28]

Water and habitable zone
The existence of liquid water, and to a lesser extent its gaseous and solid forms, on Earth are vital to the existence of life on Earth as we know it. The Earth is located in the habitable zone of the solar system; if it were slightly closer to or farther from the Sun (about 5%, or about 8 million kilometers), the conditions which allow the three forms to be present simultaneously would be far less likely to exist.[29][30]

Earth's gravity allows it to hold an atmosphere. Water vapor and carbon dioxide in the atmosphere provide a temperature buffer (greenhouse effect) which helps maintain a relatively steady surface temperature. If Earth were smaller, a thinner atmosphere would allow temperature extremes, thus preventing the accumulation of water except in polar ice caps (as on Mars).

The surface temperature of Earth has been relatively constant through geologic time despite varying levels of incoming solar radiation (insolation), indicating that a dynamic process governs Earth's temperature via a combination of greenhouse gases and surface or atmospheric albedo. This proposal is known as the Gaia hypothesis.

The state of water on a planet depends on ambient pressure, which is determined by the planet's gravity. If a planet is sufficiently massive, the water on it may be solid even at high temperatures, because of the high pressure caused by gravity, as it was observed on exoplanets Gliese 436 b[31] and GJ 1214 b.[32]

There are various theories about origin of water on Earth.

On Earth

Main articles: Hydrology and Water distribution on Earth


A graphical distribution of the locations of water on Earth.


Water covers 71% of the Earth's surface; the oceans contain 96.5% of the Earth's water. The Antarctic ice sheet, which contains 61% of all fresh water on Earth, is visible at the bottom. Condensed atmospheric water can be seen as clouds, contributing to the Earth's albedo.
Hydrology is the study of the movement, distribution, and quality of water throughout the Earth. The study of the distribution of water is hydrography. The study of the distribution and movement of groundwater is hydrogeology, of glaciers is glaciology, of inland waters is limnology and distribution of oceans is oceanography. Ecological processes with hydrology are in focus of ecohydrology.

The collective mass of water found on, under, and over the surface of a planet is called the hydrosphere. Earth's approximate water volume (the total water supply of the world) is 1,338,000,000 km3 (321,000,000 mi3).[5]

Liquid water is found in bodies of water, such as an ocean, sea, lake, river, stream, canal, pond, or puddle. The majority of water on Earth is sea water. Water is also present in the atmosphere in solid, liquid, and vapor states. It also exists as groundwater in aquifers.

Water is important in many geological processes. Groundwater is present in most rocks, and the pressure of this groundwater affects patterns of faulting. Water in the mantle is responsible for the melt that produces volcanoes at subduction zones. On the surface of the Earth, water is important in both chemical and physical weathering processes. Water and, to a lesser but still significant extent, ice, are also responsible for a large amount of sediment transport that occurs on the surface of the earth. Deposition of transported sediment forms many types of sedimentary rocks, which make up the geologic record of Earth history.

Water cycle
Main article: Water cycle


Water cycle
The water cycle (known scientifically as the hydrologic cycle) refers to the continuous exchange of water within the hydrosphere, between the atmosphere, soil water, surface water, groundwater, and plants.

Water moves perpetually through each of these regions in the water cycle consisting of following transfer processes:

evaporation from oceans and other water bodies into the air and transpiration from land plants and animals into air.
precipitation, from water vapor condensing from the air and falling to earth or ocean.
runoff from the land usually reaching the sea.
Most water vapor over the oceans returns to the oceans, but winds carry water vapor over land at the same rate as runoff into the sea, about 47 Tt per year. Over land, evaporation and transpiration contribute another 72 Tt per year. Precipitation, at a rate of 119 Tt per year over land, has several forms: most commonly rain, snow, and hail, with some contribution from fog and dew.[33] Dew is small drops of water that are condensed when a high density of water vapor meets a cool surface. Dew usually form in the morning when the temperature is the lowest, just before sunrise and when the temperature of the earth's surface starts to increase.[34] Condensed water in the air may also refract sunlight to produce rainbows.

Water runoff often collects over watersheds flowing into rivers. A mathematical model used to simulate river or stream flow and calculate water quality parameters is hydrological transport model. Some of water is diverted to irrigation for agriculture. Rivers and seas offer opportunity for travel and commerce. Through erosion, runoff shapes the environment creating river valleys and deltas which provide rich soil and level ground for the establishment of population centers. A flood occurs when an area of land, usually low-lying, is covered with water. It is when a river overflows its banks or flood from the sea. A drought is an extended period of months or years when a region notes a deficiency in its water supply. This occurs when a region receives consistently below average precipitation.

Fresh water storage
Bay of Fundy High Tide.jpgBay of Fundy Low Tide.jpg
The Bay of Fundy at high tide (left) and low tide (right)
Main article: Water resources
Some runoff water is trapped for periods of time, for example in lakes. At high altitude, during winter, and in the far north and south, snow collects in ice caps, snow pack and glaciers. Water also infiltrates the ground and goes into aquifers. This groundwater later flows back to the surface in springs, or more spectacularly in hot springs and geysers. Groundwater is also extracted artificially in wells. This water storage is important, since clean, fresh water is essential to human and other land-based life. In many parts of the world, it is in short supply.

Sea water
Main article: Seawater
Sea water contains about 3.5% salt on average, plus smaller amounts of other substances. The physical properties of sea water differ from fresh water in some important respects. It freezes at a lower temperature (about −1.9 °C) and its density increases with decreasing temperature to the freezing point, instead of reaching maximum density at a temperature above freezing. The salinity of water in major seas varies from about 0.7% in the Baltic Sea to 4.0% in the Red Sea.

Tides
Main article: Tide
Tides are the cyclic rising and falling of local sea levels caused by the tidal forces of the Moon and the Sun acting on the oceans. Tides cause changes in the depth of the marine and estuarine water bodies and produce oscillating currents known as tidal streams. The changing tide produced at a given location is the result of the changing positions of the Moon and Sun relative to the Earth coupled with the effects of Earth rotation and the local bathymetry. The strip of seashore that is submerged at high tide and exposed at low tide, the intertidal zone, is an important ecological product of ocean tides.

Effects on life



An oasis is an isolated water source with vegetation in a desert


Overview of photosynthesis and respiration. Water (at right), together with carbon dioxide (CO2), form oxygen and organic compounds (at left), which can be respired to water and (CO2).
From a biological standpoint, water has many distinct properties that are critical for the proliferation of life that set it apart from other substances. It carries out this role by allowing organic compounds to react in ways that ultimately allow replication. All known forms of life depend on water. Water is vital both as a solvent in which many of the body's solutes dissolve and as an essential part of many metabolic processes within the body. Metabolism is the sum total of anabolism and catabolism. In anabolism, water is removed from molecules (through energy requiring enzymatic chemical reactions) in order to grow larger molecules (e.g. starches, triglycerides and proteins for storage of fuels and information). In catabolism, water is used to break bonds in order to generate smaller molecules (e.g. glucose, fatty acids and amino acids to be used for fuels for energy use or other purposes). Without water, these particular metabolic processes could not exist.

Water is fundamental to photosynthesis and respiration. Photosynthetic cells use the sun's energy to split off water's hydrogen from oxygen. Hydrogen is combined with CO2 (absorbed from air or water) to form glucose and release oxygen. All living cells use such fuels and oxidize the hydrogen and carbon to capture the sun's energy and reform water and CO2 in the process (cellular respiration).

Water is also central to acid-base neutrality and enzyme function. An acid, a hydrogen ion (H+, that is, a proton) donor, can be neutralized by a base, a proton acceptor such as hydroxide ion (OH−) to form water. Water is considered to be neutral, with a pH (the negative log of the hydrogen ion concentration) of 7. Acids have pH values less than 7 while bases have values greater than 7.

Aquatic life forms
Main articles: Hydrobiology and Aquatic plant


Some of the biodiversity of a coral reef


Some marine diatoms – a key phytoplankton group
Earth surface waters are filled with life. The earliest life forms appeared in water; nearly all fish live exclusively in water, and there are many types of marine mammals, such as dolphins and whales. Some kinds of animals, such as amphibians, spend portions of their lives in water and portions on land. Plants such as kelp and algae grow in the water and are the basis for some underwater ecosystems. Plankton is generally the foundation of the ocean food chain.

Aquatic vertebrates must obtain oxygen to survive, and they do so in various ways. Fish have gills instead of lungs, although some species of fish, such as the lungfish, have both. Marine mammals, such as dolphins, whales, otters, and seals need to surface periodically to breathe air. Some amphibians are able to absorb oxygen through their skin. Invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters including breathing tubes (see insect and mollusc siphons) and gills (Carcinus). However as invertebrate life evolved in an aquatic habitat most have little or no specialisation for respiration in water.

Effects on human civilization



Water fountain
Civilization has historically flourished around rivers and major waterways; Mesopotamia, the so-called cradle of civilization, was situated between the major rivers Tigris and Euphrates; the ancient society of the Egyptians depended entirely upon the Nile. Large metropolises like Rotterdam, London, Montreal, Paris, New York City, Buenos Aires, Shanghai, Tokyo, Chicago, and Hong Kong owe their success in part to their easy accessibility via water and the resultant expansion of trade. Islands with safe water ports, like Singapore, have flourished for the same reason. In places such as North Africa and the Middle East, where water is more scarce, access to clean drinking water was and is a major factor in human development.

Health and pollution


An environmental science program - a student from Iowa State University sampling water
Water fit for human consumption is called drinking water or potable water. Water that is not potable may be made potable by filtration or distillation, or by a range of other methods.

Water that is not fit for drinking but is not harmful for humans when used for swimming or bathing is called by various names other than potable or drinking water, and is sometimes called safe water, or "safe for bathing". Chlorine is a skin and mucous membrane irritant that is used to make water safe for bathing or drinking. Its use is highly technical and is usually monitored by government regulations (typically 1 part per million (ppm) for drinking water, and 1–2 ppm of chlorine not yet reacted with impurities for bathing water). Water for bathing may be maintained in satisfactory microbiological condition using chemical disinfectants such as chlorine or ozone or by the use of ultraviolet light.

In the USA, non-potable forms of wastewater generated by humans may be referred to as greywater, which is treatable and thus easily able to be made potable again, and blackwater, which generally contains sewage and other forms of waste which require further treatment in order to be made reusable. Greywater composes 50–80% of residential wastewater generated by a household's sanitation equipment (sinks, showers and kitchen runoff, but not toilets, which generate blackwater.) These terms may have different meanings in other countries and cultures.

This natural resource is becoming scarcer in certain places, and its availability is a major social and economic concern. Currently, about a billion people around the world routinely drink unhealthy water. Most countries accepted the goal of halving by 2015 the number of people worldwide who do not have access to safe water and sanitation during the 2003 G8 Evian summit.[35] Even if this difficult goal is met, it will still leave more than an estimated half a billion people without access to safe drinking water and over a billion without access to adequate sanitation. Poor water quality and bad sanitation are deadly; some five million deaths a year are caused by polluted drinking water. The World Health Organization estimates that safe water could prevent 1.4 million child deaths from diarrhea each year.[36] Water, however, is not a finite resource, but rather re-circulated as potable water in precipitation in quantities many degrees of magnitude higher than human consumption. Therefore, it is the relatively small quantity of water in reserve in the earth (about 1% of our drinking water supply, which is replenished in aquifers around every 1 to 10 years), that is a non-renewable resource, and it is, rather, the distribution of potable and irrigation water which is scarce, rather than the actual amount of it that exists on the earth. Water-poor countries use importation of goods as the primary method of importing water (to leave enough for local human consumption), since the manufacturing process uses around 10 to 100 times products' masses in water.

In the developing world, 90% of all wastewater still goes untreated into local rivers and streams.[37] Some 50 countries, with roughly a third of the world's population, also suffer from medium or high water stress, and 17 of these extract more water annually than is recharged through their natural water cycles.[38] The strain not only affects surface freshwater bodies like rivers and lakes, but it also degrades groundwater resources.

Human uses
Further information: Water supply
Agriculture
File:Subsurface drip emission on loamy soil.ogv

Water distribution in subsurface drip irrigation.


Irrigation of field crops
The most important use of water in agriculture is for irrigation, which is a key component to produce enough food. Irrigation takes up to 90% of water withdrawn in some developing countries[39] and significant proportions in more economically developed countries (United States, 30% of freshwater usage is for irrigation).[40] It takes around 3,000 litres of water, converted from liquid to vapour, to produce enough food to satisfy one person's daily dietary need. This is a considerable amount, when compared to that required for drinking, which is between two and five litres. To produce food for the 6.5 billion or so people who inhabit the planet today requires the water that would fill a canal ten metres deep, 100 metres wide and 7.1 million kilometres long – that's enough to circle the globe 180 times.

Fifty years ago, the common perception was that water was an infinite resource. At this time, there were fewer than half the current number of people on the planet. People were not as wealthy as today, consumed fewer calories and ate less meat, so less water was needed to produce their food. They required a third of the volume of water we presently take from rivers. Today, the competition for the fixed amount of water resources is much more intense, giving rise to the concept of peak water.[41] This is because there are now nearly seven billion people on the planet, their consumption of water-thirsty meat and vegetables is rising, and there is increasing competition for water from industry, urbanisation and biofuel crops. In future, even more water will be needed to produce food because the Earth's population is forecast to rise to 9 billion by 2050.[42] An additional 2.5 or 3 billion people, choosing to eat fewer cereals and more meat and vegetables could add an additional five million kilometres to the virtual canal mentioned above.

An assessment of water management in agriculture was conducted in 2007 by the International Water Management Institute in Sri Lanka to see if the world had sufficient water to provide food for its growing population.[43] It assessed the current availability of water for agriculture on a global scale and mapped out locations suffering from water scarcity. It found that a fifth of the world's people, more than 1.2 billion, live in areas of physical water scarcity, where there is not enough water to meet all demands. A further 1.6 billion people live in areas experiencing economic water scarcity, where the lack of investment in water or insufficient human capacity make it impossible for authorities to satisfy the demand for water. The report found that it would be possible to produce the food required in future, but that continuation of today's food production and environmental trends would lead to crises in many parts of the world. To avoid a global water crisis, farmers will have to strive to increase productivity to meet growing demands for food, while industry and cities find ways to use water more efficiently.[44]

As a scientific standard
On 7 April 1795, the gram was defined in France to be equal to "the absolute weight of a volume of pure water equal to a cube of one hundredth of a meter, and to the temperature of the melting ice."[45] For practical purposes though, a metallic reference standard was required, one thousand times more massive, the kilogram. Work was therefore commissioned to determine precisely the mass of one liter of water. In spite of the fact that the decreed definition of the gram specified water at 0 °C — a highly reproducible temperature — the scientists chose to redefine the standard and to perform their measurements at the temperature of highest water density, which was measured at the time as 4 °C (39 °F).[46]

The Kelvin temperature scale of the SI system is based on the triple point of water, defined as exactly 273.16 K or 0.01 °C. The scale is an absolute temperature scale with the same increment as the Celsius temperature scale, which was originally defined according the boiling point (set to 100 °C) and melting point (set to 0 °C) of water.

Natural water consists mainly of the isotopes hydrogen-1 and oxygen-16, but there is also small quantity of heavier isotopes such as hydrogen-2 (deuterium). The amount of deuterium oxides or heavy water is very small, but it still affects the properties of water. Water from rivers and lakes tends to contain less deuterium than seawater. Therefore, standard water is defined in the Vienna Standard Mean Ocean Water specification.

For drinking
Main article: Drinking water


A young girl drinking bottled water


Water availability: fraction of population using improved water sources by country.
The human body contains from 55% to 78% water, depending on body size.[47] To function properly, the body requires between one and seven liters of water per day to avoid dehydration; the precise amount depends on the level of activity, temperature, humidity, and other factors. Most of this is ingested through foods or beverages other than drinking straight water. It is not clear how much water intake is needed by healthy people, though most advocates agree that approximately 2 liters (6 to 7 glasses) of water daily is the minimum to maintain proper hydration.[48] Medical literature favors a lower consumption, typically 1 liter of water for an average male, excluding extra requirements due to fluid loss from exercise or warm weather.[49] For those who have healthy kidneys, it is rather difficult to drink too much water, but (especially in warm humid weather and while exercising) it is dangerous to drink too little. People can drink far more water than necessary while exercising, however, putting them at risk of water intoxication (hyperhydration), which can be fatal.[50][51] The popular claim that "a person should consume eight glasses of water per day" seems to have no real basis in science.[52] Similar misconceptions concerning the effect of water on weight loss and constipation have also been dispelled.[53]



Hazard symbol for non-potable water
An original recommendation for water intake in 1945 by the Food and Nutrition Board of the United States National Research Council read: "An ordinary standard for diverse persons is 1 milliliter for each calorie of food. Most of this quantity is contained in prepared foods."[54] The latest dietary reference intake report by the United States National Research Council in general recommended (including food sources): 3.7 liters for men and 2.7 liters of water total for women.[55] Specifically, pregnant and breastfeeding women need additional fluids to stay hydrated. The Institute of Medicine (U.S.) recommends that, on average, men consume 3.0 liters and women 2.2 liters; pregnant women should increase intake to 2.4 liters (10 cups) and breastfeeding women should get 3 liters (12 cups), since an especially large amount of fluid is lost during nursing.[56] Also noted is that normally, about 20% of water intake comes from food, while the rest comes from drinking water and beverages (caffeinated included). Water is excreted from the body in multiple forms; through urine and feces, through sweating, and by exhalation of water vapor in the breath. With physical exertion and heat exposure, water loss will increase and daily fluid needs may increase as well.

Humans require water with few impurities. Common impurities include metal salts and oxides, including copper, iron, calcium and lead,[57] and/or harmful bacteria, such as Vibrio. Some solutes are acceptable and even desirable for taste enhancement and to provide needed electrolytes.[58]

The single largest (by volume) freshwater resource suitable for drinking is Lake Baikal in Siberia.[59]

Washing
The propensity of water to form solutions and emulsions is useful in various washing processes. Many industrial processes rely on reactions using chemicals dissolved in water, suspension of solids in water slurries or using water to dissolve and extract substances. Washing is also an important component of several aspects of personal body hygiene.

Transportation
The use of water for transportation of materials through rivers and canals as well as the international shipping lanes is an important part of the world economy.

Chemical uses
Water is widely used in chemical reactions as a solvent or reactant and less commonly as a solute or catalyst. In inorganic reactions, water is a common solvent, dissolving many ionic compounds. In organic reactions, it is not usually used as a reaction solvent, because it does not dissolve the reactants well and is amphoteric (acidic and basic) and nucleophilic. Nevertheless, these properties are sometimes desirable. Also, acceleration of Diels-Alder reactions by water has been observed. Supercritical water has recently been a topic of research. Oxygen-saturated supercritical water combusts organic pollutants efficiently.

Heat exchange
Water and steam are used as heat transfer fluids in diverse heat exchange systems, due to its availability and high heat capacity, both as a coolant and for heating. Cool water may even be naturally available from a lake or the sea. Condensing steam is a particularly efficient heating fluid because of the large heat of vaporization. A disadvantage is that water and steam are somewhat corrosive. In almost all electric power stations, water is the coolant, which vaporizes and drives steam turbines to drive generators. In the U.S., cooling power plants is the largest use of water.[40]

In the nuclear power industry, water can also be used as a neutron moderator. In most nuclear reactors, water is both a coolant and a moderator. This provides something of a passive safety measure, as removing the water from the reactor also slows the nuclear reaction down – however other methods are favored for stopping a reaction and it is preferred to keep the nuclear core covered with water so as to ensure adequate cooling.

Fire extinction


Water is used for fighting wildfires.
Water has a high heat of vaporization and is relatively inert, which makes it a good fire extinguishing fluid. The evaporation of water carries heat away from the fire. It is dangerous to use water on fires involving oils and organic solvents, because many organic materials float on water and the water tends to spread the burning liquid.

Use of water in fire fighting should also take into account the hazards of a steam explosion, which may occur when water is used on very hot fires in confined spaces, and of a hydrogen explosion, when substances which react with water, such as certain metals or hot carbon such as coal, charcoal, coke graphite, decompose the water, producing water gas.

The power of such explosions was seen in the Chernobyl disaster, although the water involved did not come from fire-fighting at that time but the reactor's own water cooling system. A steam explosion occurred when the extreme overheating of the core caused water to flash into steam. A hydrogen explosion may have occurred as a result of reaction between steam and hot zirconium.

Recreation


Grand Anse Beach, St. George's, Grenada, West Indies.
Main article: Water sport (recreation)
Humans use water for many recreational purposes, as well as for exercising and for sports. Some of these include swimming, waterskiing, boating, surfing and diving. In addition, some sports, like ice hockey and ice skating, are played on ice. Lakesides, beaches and water parks are popular places for people to go to relax and enjoy recreation. Many find the sound and appearance of flowing water to be calming, and fountains and other water features are popular decorations. Some keep fish and other life in aquariums or ponds for show, fun, and companionship. Humans also use water for snow sports i.e. skiing, sledding, snowmobiling or snowboarding, which requires the water to be frozen.

Water industry


A water-carrier in India, 1882. In many places where running water is not available, water has to be transported by people.


A manual water pump in China


Water purification facility
The water industry provides drinking water and wastewater services (including sewage treatment) to households and industry. Water supply facilities include water wells cisterns for rainwater harvesting, water supply network, water purification facilities, water tanks, water towers, water pipes including old aqueducts. Atmospheric water generators are in development.

Drinking water is often collected at springs, extracted from artificial borings (wells) in the ground, or pumped from lakes and rivers. Building more wells in adequate places is thus a possible way to produce more water, assuming the aquifers can supply an adequate flow. Other water sources include rainwater collection. Water may require purification for human consumption. This may involve removal of undissolved substances, dissolved substances and harmful microbes. Popular methods are filtering with sand which only removes undissolved material, while chlorination and boiling kill harmful microbes. Distillation does all three functions. More advanced techniques exist, such as reverse osmosis. Desalination of abundant seawater is a more expensive solution used in coastal arid climates.

The distribution of drinking water is done through municipal water systems, tanker delivery or as bottled water. Governments in many countries have programs to distribute water to the needy at no charge.

Reducing usage by using drinking (potable) water only for human consumption is another option. In some cities such as Hong Kong, sea water is extensively used for flushing toilets citywide in order to conserve fresh water resources.

Polluting water may be the biggest single misuse of water; to the extent that a pollutant limits other uses of the water, it becomes a waste of the resource, regardless of benefits to the polluter. Like other types of pollution, this does not enter standard accounting of market costs, being conceived as externalities for which the market cannot account. Thus other people pay the price of water pollution, while the private firms' profits are not redistributed to the local population victim of this pollution. Pharmaceuticals consumed by humans often end up in the waterways and can have detrimental effects on aquatic life if they bioaccumulate and if they are not biodegradable.

Wastewater facilities are storm sewers and wastewater treatment plants. Another way to remove pollution from surface runoff water is bioswale.

Industrial applications
Water is used in power generation. Hydroelectricity is electricity obtained from hydropower. Hydroelectric power comes from water driving a water turbine connected to a generator. Hydroelectricity is a low-cost, non-polluting, renewable energy source. The energy is supplied by the motion of water. Typically a dam is constructed on a river, creating an artificial lake behind it. Water flowing out of the lake is forced through turbines that turn generators.



Three Gorges Dam is the largest hydro-electric power station.
Pressurized water is used in water blasting and water jet cutters. Also, very high pressure water guns are used for precise cutting. It works very well, is relatively safe, and is not harmful to the environment. It is also used in the cooling of machinery to prevent overheating, or prevent saw blades from overheating.

Water is also used in many industrial processes and machines, such as the steam turbine and heat exchanger, in addition to its use as a chemical solvent. Discharge of untreated water from industrial uses is pollution. Pollution includes discharged solutes (chemical pollution) and discharged coolant water (thermal pollution). Industry requires pure water for many applications and utilizes a variety of purification techniques both in water supply and discharge.

Food processing


Water can be used to cook foods such as noodles.
Water plays many critical roles within the field of food science. It is important for a food scientist to understand the roles that water plays within food processing to ensure the success of their products.

Solutes such as salts and sugars found in water affect the physical properties of water. The boiling and freezing points of water are affected by solutes, as well as air pressure, which is in turn affected by altitude. Water boils at lower temperatures with the lower air pressure which occurs at higher elevations. One mole of sucrose (sugar) per kilogram of water raises the boiling point of water by 0.51 °C, and one mole of salt per kg raises the boiling point by 1.02 °C; similarly, increasing the number of dissolved particles lowers water's freezing point.[60] Solutes in water also affect water activity which affects many chemical reactions and the growth of microbes in food.[61] Water activity can be described as a ratio of the vapor pressure of water in a solution to the vapor pressure of pure water.[60] Solutes in water lower water activity. This is important to know because most bacterial growth ceases at low levels of water activity.[61] Not only does microbial growth affect the safety of food but also the preservation and shelf life of food.

Water hardness is also a critical factor in food processing. It can dramatically affect the quality of a product as well as playing a role in sanitation. Water hardness is classified based on the amounts of removable calcium carbonate salt it contains per gallon. Water hardness is measured in grains; 0.064 g calcium carbonate is equivalent to one grain of hardness.[60] Water is classified as soft if it contains 1 to 4 grains, medium if it contains 5 to 10 grains and hard if it contains 11 to 20 grains.[vague] [60] The hardness of water may be altered or treated by using a chemical ion exchange system. The hardness of water also affects its pH balance which plays a critical role in food processing. For example, hard water prevents successful production of clear beverages. Water hardness also affects sanitation; with increasing hardness, there is a loss of effectiveness for its use as a sanitizer.[60]

Boiling, steaming, and simmering are popular cooking methods that often require immersing food in water or its gaseous state, steam. Water is also used for dishwashing.

Water law, water politics and water crisis

Main articles: Water law, Water right, and Water crisis


An estimate of the share of people in developing countries with access to potable water 1970–2000
Water politics is politics affected by water and water resources. For this reason, water is a strategic resource in the globe and an important element in many political conflicts. It causes health impacts and damage to biodiversity.

1.6 billion people have gained access to a safe water source since 1990.[62] The proportion of people in developing countries with access to safe water is calculated to have improved from 30% in 1970[63] to 71% in 1990, 79% in 2000 and 84% in 2004. This trend is projected to continue.[7] To halve, by 2015, the proportion of people without sustainable access to safe drinking water is one of the Millennium Development Goals. This goal is projected to be reached.

A 2006 United Nations report stated that "there is enough water for everyone", but that access to it is hampered by mismanagement and corruption.[64] In addition, global initiatives to improve the efficiency of aid delivery, such as the Paris Declaration on Aid Effectiveness, have not been taken up by water sector donors as effectively as they have in education and health, potentially leaving multiple donors working on overlapping projects and recipient governments without empowerment to act.[65]

The authors of the 2007 Comprehensive Assessment of Water Management in Agriculture cited poor governance as one reason for some forms of water scarcity. Water governance is the set of formal and informal processes through which decisions related to water management are made. Good water governance is primarily about knowing what processes work best in a particular physical and socioeconomic context. Mistakes have sometimes been made by trying to apply 'blueprints' that work in the developed world to developing world locations and contexts. The Mekong river is one example; a review by the International Water Management Institute of policies in six countries that rely on the Mekong river for water found that thorough and transparent cost-benefit analyses and environmental impact assessments were rarely undertaken. They also discovered that Cambodia's draft water law was much more complex than it needed to be.[66]

The UN World Water Development Report (WWDR, 2003) from the World Water Assessment Program indicates that, in the next 20 years, the quantity of water available to everyone is predicted to decrease by 30%. 40% of the world's inhabitants currently have insufficient fresh water for minimal hygiene. More than 2.2 million people died in 2000 from waterborne diseases (related to the consumption of contaminated water) or drought. In 2004, the UK charity WaterAid reported that a child dies every 15 seconds from easily preventable water-related diseases; often this means lack of sewage disposal; see toilet.

Organizations concerned with water protection include International Water Association (IWA), WaterAid, Water 1st, American Water Resources Association. The International Water Management Institute undertakes projects with the aim of using effective water management to reduce poverty. Water related conventions are United Nations Convention to Combat Desertification (UNCCD), International Convention for the Prevention of Pollution from Ships, United Nations Convention on the Law of the Sea and Ramsar Convention. World Day for Water takes place on 22 March and World Ocean Day on 8 June.

Water used in the production of a good or service is virtual water.

In culture

Religion
Main article: Water and religion
Water is considered a purifier in most religions. Major faiths that incorporate ritual washing (ablution) include Christianity, Hinduism, Islam, Judaism, Rastafari movement, Shinto, Taoism, and Wicca. Immersion (or aspersion or affusion) of a person in water is a central sacrament of Christianity (where it is called baptism); it is also a part of the practice of other religions, including Islam (Ghusl), Judaism (mikvah) and Sikhism (Amrit Sanskar). In addition, a ritual bath in pure water is performed for the dead in many religions including Islam and Judaism. In Islam, the five daily prayers can be done in most cases after completing washing certain parts of the body using clean water (wudu), unless water is unavailable (see Tayammum). In Shinto, water is used in almost all rituals to cleanse a person or an area (e.g., in the ritual of misogi). Water is mentioned numerous times in the Bible, for example: "The earth was formed out of water and by water" (NIV). In the Qur'an it is stated that "Living things are made of water" and it is often used to describe paradise.

Philosophy
The Ancient Greek philosopher Empedocles held that water is one of the four classical elements along with fire, earth and air, and was regarded as the ylem, or basic substance of the universe. Water was considered cold and moist. In the theory of the four bodily humors, water was associated with phlegm. The classical element of Water was also one of the five elements in traditional Chinese philosophy, along with earth, fire, wood, and metal.

Water is also taken as a role model in some parts of traditional and popular Asian philosophy. James Legge's 1891 translation of the Dao De Jing states "The highest excellence is like (that of) water. The excellence of water appears in its benefiting all things, and in its occupying, without striving (to the contrary), the low place which all men dislike. Hence (its way) is near to (that of) the Tao" and "There is nothing in the world more soft and weak than water, and yet for attacking things that are firm and strong there is nothing that can take precedence of it—for there is nothing (so effectual) for which it can be changed."[67]

Thales, who was portrayed by Aristotle as an astronomer and an engineer, theorized that the earth, which is denser than water, emerged from water. Thales, a monist, believed further that all things are made from water. Plato believed the shape of water is icosahedron which accounts for why it is able to flow easily compared to the cube shaped earth. [68]

Literature
Water is used in literature as a symbol of purification. Examples include the critical importance of a river in As I Lay Dying by William Faulkner and the drowning of Ophelia in Hamlet.

Sherlock Holmes held that "From a drop of water, a logician could infer the possibility of an Atlantic or a Niagara without having seen or heard of one or the other."[69]

The Relationship
Between Man öAnd The Natural World

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While the starting point of any reformative transformation stems from the will of the individual human being, this reform is reflected in the way that man deals with her/himself as part of nature, and deals with the natural world as part of her/himself. By reaching this stage of awareness, the oneness of Allah means for her/him the oneness of life.

The unity of life is very apparent concept in the Islamic teachings:

Glory to Allah, Who created in pairs all things that the earth produces, as well as their own (human) kind and (other) things of which they have no knowledge (HQ: 36: 33- 36).

There is not an animal (that lives) on the earth, nor a being that flies on its wings, but (forms part of) communities like you. Nothing have We omitted from the Book, and they (all) shall be gathered to their Lord in the end (HQ: 6: 38).

That is, all creatures are coming from one origin and returning to that origin. To Allah everything returns. Therefore, all creatures belong to one another.

Unity of life should be brought to man's awareness always because it represents an aspect of experiencing the oneness of Allah. According to this principle, man builds her/his relationship with nature, and with her/his fellow man. In her/his way to fulfill her/his earthly needs, s/he should not violate that principle.

Fulfilling her/his needs is not a simple response as it is in the animal kingdom. It is related to complex sets of relationships, between man and the natural kingdom (animals, birds and plants), between her/him and her/himself (is s/he greedy or self – controlled?), between her/him and her/his fellow human beings (with whom s/he shares and to whom s/he provides) and between her/him and the society where s/he should respect others’ ownership and privacy.

While her/his ultimate goal is to be a Servant of Allah, s/he should start her/his earthly journey, using the gifts that would make achieving that goal possible. Man, as a vicegerent of Allah, should behave out of this understanding, and strive to be worthy of that rank. He should be just to himself by being just to everything in the world; not to destroy a plant, shoot birds for pleasure, hurt an animal. S/he should respect life everywhere. The respect of life went to the extent that The Prophet (PBUH) advised believers to continue planting even if they foresee the coming of Doomsday.glossary

This respect of the unity of life serves two purposes, it emphasizes humans’ awareness of the Divine Law and its manifestations and, as such, encourages man to seek understanding of the Divine Law within the natural world. Out of this understanding, science develops. On the other hand, it creates an awesome feeling within man's heart, observing the Creator within His own creatures. Out of this inner interaction, art comes through.

… whithersoever ye turn, there is Allah's countenance. (HQ: 2:115).

As vicegerent of Allah, man is asked to build and invest not to destroy or mischief

Allah loveth not mischief (HQ: 2: 205).

Out of respect to Allah's creations, man should think and try to understand the relationship between the natural phenomena and to be aware not to misuse the natural gifts.





Man's Physical Body
As Part of the Natural World





Man's responsibility for her/his physical body is interrelated to her/his responsibility towards nature. To take care of her/his health and well-being can be accomplished without aggression on the natural world:

So eat and drink of the sustenance provided by Allah. And do no evil nor mischief on the (face of the) earth (HQ:2:60).

We are supposed to deal with our own body as part of the natural world. Therefore, we have to take care of it and fulfill its requirements without being indulged in its desires and lusts.

The Prophet (PBUH) says,

“It is enough for the child of Adam to feed her/himself with an amount of food that keeps her/him going" (PH).

Narrated by Ahmed, and Al Tirmidhi

In order to achieve the required balance, we need to remove the contradictions that exist between the earthly requirements and the spiritual longing. Therefore, we have to be aware that our physical existence is a gift from Allah that we should be thankful for, and that taking care of our body is a sacred task and an expression of gratitude to our Creator. In other words, our body acquires its importance as a tool through which our spirit expresses itself. It is understood that Allah provides us with instincts to keep our survival on earth. Assured that we are here for a purpose and that each of us has a mission, we should then try fulfilling our mission through this physical existence and take care of this tool.

In order to fulfill our physical needs we come across the natural world. For example, in order to survive, we need to eat. The teachings of Islam came to include a divine dimension with the way that man fulfills her/his needs. The general rule is that man was advised to say "in the name of Allah", before any action s/he intends to do. That statement stands as a continuous reminder that we have to be up to the meaning of the divine words that we utter. The implication is, we become tools in the hand of the Divine and we do what we do in His name. Out of respect to Allah who gives us that position, we should not exceed our limits, and we should always make a balance between satisfying our needs and protecting the natural resources.

Because all revelations natural and prophetic, including the teachings of Muhammad (PBUH) , respect Life in all its manifestations, it is understandable why killing an animal for consumption becomes a problem in some non-prophetic revelations. However, this seeming paradox between respecting life in all its manifestations and using animal as human food is resolved in Islam. The belief in the oneness of life and the unity of all its aspects implies that eating the meat of animal’s means that the life of the animal nourishes the life of man, and as such this animal's soul is blessed by moving to a higher level of existence. As such slaughtering animals for food consumption is allowed but according to certain values and regulations that reflect the oneness of all.glossary

During the act of the slaughtering the person must pray for the animal soul by saying "in the name of Allah. Allah is Great". Man is addressing the soul and asking it to surrender to Allah's will. The act of slaughtering should be done with a very sharp knife and directed to the neck nerve quickly without hesitation, that is, to minimize the animal's or the bird’s pain. This act should never ever be done in the presence of another animal(s), not to scare them. There is a clear order that the animals that are slaughtered without following those procedures, their meat is forbidden to eat. And it is considered a sinful action for its doer.

We, thus, have to be careful, and not to indulge ourselves in any sabotaging actions. We become more and more aware of the inner connection that ties us, humans, to the whole. With a growing awareness of that connection, we become more balanced. To be in balance requires a continuous self-observation and be open to the inspiration of Revelations without being fanatic and literal.

In other words, while man's search for satisfying her/his physical needs are considered "naturally legitimate", fulfilling those needs should be in harmony with the objective of creation. In fulfilling those needs, s/he humanizes them by elevating them from the instinctive animalistic level to meaningful responses that are purely human. While so doing, s/he is not causing harm to other aspects of life, rather helping them also fit into the purpose of their existence.

The teachings of Islam mean to facilitate man's life, and not to complicate it. For example, it would be impossible for people who live in deserts to live without depending on the sheep products. This is one of the reasons that meat is allowed. In our modern time, we came also to realize that meat and animal products provide the human body with essential amino acids that are not supplemented through other food resources.

Facilitating man's life goes to allow in certain circumstances what is forbidden otherwise. If man is obliged to eat forbidden food to survive, s/he is encouraged to do so:

But if one is forced by necessity, without wilful disobedience, nor transgressing due limits, then is he guiltless. For Allah is Oft-Forgiving, Most Merciful (HQ: 2:173).





óRediscovering the Oneness of Life
through Science and Art



Man is linked to the natural world, not just to satisfy her/his basic needs, but also in order to appreciate the order according to which the natural world was created. This appreciation is reflected in man's ability to relate between the natural phenomena, searching for rules that regulate those phenomena. It was also reflected in the deep contemplation, which resulted in learning about the Divine through artistic works as they appear in great civilizations.

Unity of life was revealed to man through her/his developing knowledge about the world and through her/his contemplations and meditation. Many verses in the Holy Qur’an push man to work her/his mind and heart, and criticize those “without understanding”

Islam responded to human quest for how to make the earthly life spiritually fruitful, by directing her/his way. Man is asked to make use of her/his potentials. Because s/he was created with the ability to think, s/he should use her/his mind to find continuously what is better for her/him. Her/his senses should be purified to listen to the hidden messages that are embedded in the natural world. Her/his worldly activities should then describe her/his appreciation to Allah's gifts within her/himself and in the world. That can be reflected in Islam's encouragement to science where our mental power is used and in art where the hidden insight of the heart takes the lead. That cohesion between mind and heart, reason and passion is highly recommended in Islamic teachings. That cohesion between mind and heart, reason and passion is another expression of the balance that is pointed at in The Prophet's teaching by the term al-amr al-wast.

Science

When man observes the order in the natural world, s/he becomes curious about decoding the relationships within natural phenomena. Responding to this curiosity, the Holy Qur’an and The Prophet’s teachings encouraged man to search and think of everything. The Prophet (PBUH) encouraged people to acquire knowledge even if it is in the end of the world.

He says,

“S/he who chooses a way of life where seeking knowledge is her/his prime goal, God paves her/his way to Heaven (PH).

Narrated by Al Tirmidhi and Ahmad.

“Seeking Knowledge is a religious commandment for all Muslims”(PH).

Narrated by Ibn Magah.

The Holy Qur'an constantly advises man to roar the earth and see the secrets of creation on all levels:

Would not they go and see how camels are created. How the sky is raised high. How the mountains are fixed firm. How the earth is spread out (HQ: 88: 17- 20).

Now let man consider how he came into an earthly existence. He is created from a gushing fluid. Proceeding from between the backbone and the ribs (HQ: 86: 5- 7).

Science is based on the fact that there is an order in the universe. For believers, that order is a manifestation of the Divine Law. Science explains the oneness of life in a magnificent way.

Thou canst see no fault in the Beneficent One’s creation; then look again: Canst thou see any rifts? (HQ: 67: 3)

It has become known for every one that there is such a striking similarities between the smallest order men could observe in the living cell and the solar system. Those similarities clarify that there is one Order that points to the One Creator Who is Omnipresent within His creatures, and He connects them in a way that will remain always beyond our limited abilities to discover. So, regardless of man's growing knowledge, s/he remains in the state of wonder since the more s/he knows, the more s/he realizes that s/he does not know. Out of this limitation, s/he may get to be aware of The All Knowable.

It is well understandable that the holy text is not a source of scientific knowledge. However, it is amazing that what we know now, as scientific facts do not contradict with what comes in the verses of the Holy Qur’an. Moreover, there are certain verses that were not clear enough at the time of the Revelation and they are becoming understandable with reference to the scientific discovery. The examples are numerous, and there are many books that are written to deal with that subject. Our interest here is not to speculate upon the relationship between the Holy Qur’an and the scientific knowledge. Rather, we are interested in the fact that the Holy Qur’an and the teachings of The Prophet (PBUH) guide human beings to think, contemplate and interact with the natural world.

The Prophet (PBUH) himself was ready to learn from his companions about the natural world. When he found out that the palm trees did not produce dates because of his advice as not to germinate them, he told his companions to do as they had used to do. He told them, “you know better in the affairs of this life”.glossary As such, there should be no confusion between the spiritual knowledge and the scientific one. Spiritual guides are not necessarily knowledgeable of the latest scientific findings, but they believe in the Divine Order that is revealed in the natural one. Scientists pursue objective observations and they should be highly disciplined in order to achieve that goal.

In few words, to know better about the world is a recommendation that goes in harmony with believing in the one order and the oneness of life. It is because of that fact, Islamic culture was open to all other cultures and civilizations and it contributed to the scientific knowledge a great deal.

What are Endangered Species?

Rare, endangered, or threatened plants and animals are elements of our natural heritage that are declining rapidly or are on the verge of vanishing. They are plants and animals that exist in small numbers that may be lost forever if we do not take quick action to stop their decline. If we cherish these species, like we do other rare and beautiful objects, these living organisms become treasures of the highest magnitude.