A Sweet Briar College Learning Resource
BIOLOGY and WATER
Professor Linda S. Fink
The remarkable chemical and physical properties of water, primarily resulting from hydrogen bonding, have major consequences for all living organisms.
The properties of water place limits on organisms -- on their physiology, anatomy, behavior, distributions, and evolution -- but simultaneously provide evolutionary and ecological opportunities.
1. Hydrogen bonding
means that water
molecules are cohesive (they 'stick' to one another
and to other polar molecules) and that surface tension makes
air-water boundaries distinctive microhabitats.
Pure water freezes at 0C but is most dense at 4 C.
That is, solid water (ice) is less dense than cold liquid water.
has a high heat capacity: it takes much more heat to raise the
temperature of a volume of water than the same volume of air.
4. The three factors
listed above will probably be all that we can cover in one class meeting.
These are not, however, the only important physical and chemical properties
that affect living organisms.
can predict a lot about life from the physical and chemical properties
of water. Does this mean that chemistry and physics are sufficient to
understand how living organisms deal with water? No...
In your field trip on Thursday with Dr. Paul Gier you will see a diversity of freshwater vertebrates and invertebrates and will be able to relate many of their adaptations to the properties of water described here.
H20 - The Mystery, Art, and Science of Water
Chris Witcombe and Sang Hwang
Sweet Briar College