Water’s importance in biological processes in living organisms and as an environment for these living organisms.

Water in living organism makes up about 70%-90% of the organism, which is very useful for keeping the organism at a constant temperature through thermoregulation as water has a high specific heat capacity. This means that it takes a lot of energy to raise the temperature of water, therefore water will remain at a constant temperature which is ideal for a animals: whereby a small temperature fluctuation inside the body could have disastrous effects, particularly with regard to the effectiveness of enzymes. The resistance to heat change is caused when the substance is heated, instead of all the molecule vibrating, like they do when at other substances are heated, just the hydrogen atoms vibrate which absorbs a lot of the energy put into heating the water as a whole. Water is also used to cool us down by sweating, this can happen because water as a high latent heat of vaporization, so when we sweat we transfer a lot of energy into evaporating the liquid and subsequently it cools the body with a minimal water loss.

Water is a cohesive substance whereby the molecules will stick together making it a substance which is not easily compressed thus making it ideal for the support role it plays in the plants transpiration stream. Also this cohesive property is vital in the development of a foetus, as the amniotic fluid in the amniotic sac is made up largely of water which gives support to the growing baby inside the womb.

As water is a viscous substance it is ideal for lubrication within body for example pleural fluid is made up largely of water and it helps to minimise friction between the lungs and the rib cage.

The properties that make water so fundamental in the biological processes of animals are the same properties that give water its ideal characteristics as a living environment upon which so many varieties of species thrive in. Water covers around 2/3 of earth and houses millions of animals all of which have evolved to use water's properties to gain the best chance of survival possible.

When there is such a large expanse of water, an ocean for example, it is important that the water stays fairly constant in all aspects but in particular temperature .Water is slow to change temperature when in large volumes which is ideal for the animals living inside it which would be negatively affected by too larger temperature fluctuation. If the outside temperature does fall too low then the water on the surface will become less dense and expand to form ice, this acts as an insulation layer for the body of water underneath and thus keeps the animals safe from freezing over. Water expands upon freezing because as the water cools the molecules slow down until they are sufficiently slow for the separate H2O to form their maximum number of weak hydrogen bonds with each other. One water molecule can bond with four other water molecules but in order to do this the separate molecules must move apart in order to create space and thus the water expands and turns to ice. Ice is also an environment for animal such as penguins and polar bears which live on top of the ice which floats at the north and south poles. There is another advantage to gain from the forming of ice and that it is gives a change in density helps all the water to circulate and thus all the nutrients is circulated throughout the ocean.

Water has transparency, which is absolutely vital as it allows visible light to penetrate through the water. This in turn gives the light plants need to photosynthesise and creates a building block for ecosystems within the water to flourish and grow.

On ponds the surface of water can act as an environment for small bugs such as pond skaters. The pond skaters can walk on top of the water without sinking, this is because water has a high surface tension due to the cohesion between the water molecules in other words small insects are able to walk on water because the force they exert on the water is less than the cohesion between the molecules and therefore the small inter-molecular hydrogen bonds are not broken and surface remains flat and strong enough for the insects to walk on.

The volatility and stability of water is in fine balance with the changing of temperature of the earth so that a water cycle can be maintained whereby water is transported and deposited in different places feeding ecosystems everywhere.

Sometimes waters life-giving properties can work in the opposite way intended and actually do damage for example because water is such a good solvent many harmful chemicals can pass into it unchecked and unseen and be transported very quickly doing damage to any ecosystems it comes across. An other example would be that because water so ideal for living in , it is a breeding ground for human harming bacteria which causes diseases such as cholera ,so people, particularly in third world countries, who don't have access to clean treated water will be afflicted with such diseases because they have to drink the dirty water in order to survive.

Water is something we take for granted, we always expect it on tap and never truely give much though to the necessity of it, without water life would cease to exist.