BIOL 1201 Chapter : Biology 1201 Chapter 3
Document Summary
Water is the only common substance to exist on earth in all 3 states of matter: solid, liquid, and gas. Life on earth began in water and evolved there for 3 billion years before it spread to land. All living organisms require water more than any other substance. Human beings can survive for several weeks without food, but no more than 1 week without water. The polarity of water molecules makes water a good solvent for molecules that have charged regions (i. e. polar molecules) or atoms that are charged (i. e. charged regions (i. e. polar molecules) or atoms that are charged (i. e. ions) There are four emergent properties of water that contribute to earth"s fitness for life: cohesive behavior, ability to moderate temperature, expansion upon freezing, versatility as a solvent. Example water molecules being held together by hydrogen bonds. Adhesion - attraction bt unlike molecules ( water molecules being held to cell walls by hydrogen bonds )
