The Role of Water in the Lives of Organisms
Water is perhaps the most important molecule for the survival and life
of all living organisms because there is a wide spectrum of roles that
it plays. The fact that the earth's surface consists of 70.8% water
shows its significance and importance.
Firstly, water has the chemical formula Hg0 (two Hydrogen atoms to one
Oxygen atom), the covalent bonds between which create cohesive forces.
Water has a very high specific heat capacity, measuring 4,200 Joules,
creating a stable environment for organisms to live in. This means
that water does not heat up or cool down too rapidly due to the
difficulty in breaking the hydrogen bonds, which restricts the
movement of the water molecules. This property of water is beneficial
to aquatic organisms (e.g. Fish, Jellyfish), as they do not have to
keep adapting their own body temperatures for survival.
Another property water has is its insulating nature in lakes and
rivers. As water cools toward 0°C, the water molecules slow down to
form the maximum number of hydrogen bonds. As this process continues,
water molecules must give enough space for all four hydrogen bonds to
fit, causing the water to expand as it freezes to form ice. Ice is
less dense than the liquid form and therefore floats, a property very
significant to the survival of fish as this layer of ice insulates the
liquid water below to prevent the whole lake or river to freeze.
Otherwise, this could be fatal for many organisms in the aquatic food
Aquatic plants can survive in deep waters due to the fact that water
is a transparent liquid. As it is transparent, sunlight can reach the
plants helping them to photosynthesis and stay alive. This benefits
both the aquatic plants as well as the higher order organisms that
feed off these plants, as photosynthesis is the process where plants
make their food. These sugars are transported to different areas of a
plant in water.
Water functions as a transport medium in both animals (including
humans) and plants. In humans, water is within the blood substance and
because water molecules slide past each other easily blood can be
easily transported through narrow capillaries. A vital role because if
this were not the case, blood would not be able to transport bodily
pigments (e.g. hormones, white blood cells, red blood cells, proteins
etc) around the body as efficiently risking vast numbers of health
problems. Water also allows waste materials such as urea and urine to
be dissolved, transported and excreted, preventing them becoming toxic
and harming the organism that has produced them during metabolic
activities. A role in the transport of gametes in animals (e.g. sperm