Re: How is water's high specific heat capacity important for living organisms?

The specific heat capacity of a substance is the energy needed to 
increase the temperature of 1 kilogram of that substance by 1 degree 
Celsius (or Kelvin).  This term has SI units of joules per kilogram 
kelvin, and for water the value is 4186 J/kgK.

A substance with a high heat capacity will need much more energy to raise 
its temperature, and since cells are mostly water, it will take a large 
amount of energy to raise body temperature by a significant amount.  This 
prevents our bodies from reaching excessive temperatures that can be 
harmful to us.  In addition, since chemical reactions in living organisms 
can produce large amounts of energy, it is neccessary that water can 
absorb this heat without it affecting its temperature. Water's high heat 
capacity is also important for aquatic organisms.


Arms & Camp,  "Biology."  4th edition. Saunders College Publishing : 
Florida. 1995.

Wikipedia encyclopedia 
   http://en.wikipedia.org/wiki/Specific_heat_capacity