Posted at 10.05.2018
Discuss the assertion that water has several unique properties that make it vital not only for human beings, but also for all living organisms to survive.
Water is an essential aspect of all living organisms' plants and animals alike. What makes it so useful and highly relevant to survival are its unique properties which relate with its functions and therefore its relevance to living things as discussed below.
Water is a dipolar molecule
Water is a standard oxide of hydrogen comprising two hydrogen molecules covalently bonded to one oxygen molecule. This particular molecule is not linear and the oxygen atom has higher electro negativity than the hydrogen atoms. The atoms of oxygen carry a slightly negative charge whereas, the hydrogen atoms are slightly positive, this gives this inflatable water molecule its dipole movement (en. wikipedia. org). Hence, the water molecule can develop up to four bonds with it self and other molecules. This property gives water most of its properties.
Water is a Universal solvent
A solvent is a liquid which dissolves other substances. Due to its ability to create four bond with other molecules (dipole), no other chemically inert solvent can dissolve a number of materials as water nor the amount of them it can take in solution (Edward J. K 1996). Water can dissolve a number of substances solids, liquids and gases alike. (Edward, 1999) adds on to say "water is the better solvent and a medium for the movement of molecules within and outside the cell. " hence water is important in both plants and animals for the reason that it aids movement of materials through diffusion as salts, sugars acids, alkalis and gases such as skin tightening and (carbonation) and oxygen dissolve in it and can be transported in the organism as a transport medium as with blood, lymphatic and excretory system, the alimentary canal and xylem and phloem (Taylor D. J 1984).
Water is wet
Because of its molecules forming hydrogen bonds with other polar molecules, water makes things wet. This is due to its cohesive and adhesive properties (Dr. Jain VK, 1974). Cohesion is the attraction between like molecules in this case water while adhesion is the attraction of molecules of different substances. This gives water high capillary forces, that is the tendency of water to move up a narrow tube contrary to the concentration gradient. This is an essential property to vascular plants such as trees as it allows water to move along very narrow spaces such as during transpiration that assist control the temperature of your plant.
Its cohesion property is also relevant in cells and in translocation of water through xylem in plants. That is also vital in the rising or moving up of sap in plants.
The cohesive property of water results in surface tension. Besides mercury, water has the greatest tendency to cohere triggering its surface to contract to the tiniest possible areas as a result of the hydrogen bonds (Edward J. K, 1996), due to this many small organisms have the ability to choose water or skate over its surface, thus providing them a habitat, including the water striders. It also aids reproduction by using seed dispersal, garmetes and larval stages of aquatic organisms.
Water has a higher specific heat capacity
The specific heat capacity of water is the quantity of heat necessary to raise one (1) gram of water from O0C to 10C. In comparison to other liquids a considerably high amount of energy is required to change the temperature of water (Edward J. K, 1996). This property is also due to the numerous hydrogen bonds between water molecules. This is very vital to both humans and plants as it can help in moderating the earth's climate by buffering large fluctuations in temperature. In addition, it protects the plants from very harmful temperature fluctuations. High specific heat capacity of water is also vital to marine and fresh bodies of water to help maintain a regular temperature over longer time period and be stable over short periods of time.
Latent heat of vaporization
Vaporization or evaporation is the change of state from liquid to gas. The latent heat of vaporization is the vitality required to convert a liquid into gas (Vapour) at continuous temperature (Dr V. K Jain, 1974). Water gets the highest latent heat of vapourisation of most common substances which is about 44 Kj/Mol at 250C. The high latent heat of vaporization of water enables the plants to cool themselves by giving out heat through transpiration. It is also a major factor in the transfer of heat between your ocean and the atmosphere, thereby driving the weather climate. Beside these, animals also use this property in cooling by the sweating and panting in mammals. That's, the opening of the mouth by some reptile's e. g crocodiles in sunshine and mammals like dogs.
Latent heat of fusion
Latent heat of fusion is heat required to convert a unit of mass of a good to liquid at the same temperature. To melt 1gram of ice at 00C, 80cal. (335J) of energy is needed which is very high and caused by the occurrence of hydrogen bonds. This means water must loose a comparatively large amount of heat energy to freeze. This can help protect the contents of the cells not to be damaged as their environments are less likely to freeze.
Water expansion and density
One of the unique properties of water is the fact, it reaches its maximum density at 40C and diminishes above and below that temperature. It has a tendency to expand as it freezes and its density is decreased (Dr. Jain V. K, 1974), hence ice has a lower density than water and floats together with oceans, lakes and rivers. It forms at the top first and last at the bottom, this provides insulation of the below it and improve the likelihood of survival for acquatic organisms especially in cold climates and during cold seasons.
Penetration of light
Water without any suspended particles is transparent in the visible electro magnetic spectrum. Therefore relatively great amounts of infrared and ultra-violet rays can penetrate through it.
This allows acquatic plants to survive as they are able to carry out photosynthesis.
It can therefore be deducted that water indeed has several unique properties related to its importance to all or any living organism without which almost all of these might become extinct. Besides these water offers a habitat for millions of living organisms and is also also essential in sanitation for human beings helping to prevent the spread of infections such as viruses, protozoa and worms. Hence, water is an extremely essential aspect without which life may not exist.
Edward J. K (1996), Concepts of Ecology; fourth edition. Pearson Education. New Jersey.
en. Wikipedia. org/wiki/water
Dr. Jain V. K (1974), fundamentals of Plant Physiology; S. Chand and Company Ltd. New Dhehi
Taylor D. J et al (1984), Biological Science 1 & 2, Cambridge University Press. New York.