Living organisms survive by using thousands of chemicals, each involved in a long series of complex chemical reactions. For example, the clotting of blood involves over twenty distinct individual reactions, each of which is absolutely vital to heal a wound. However, clotting could be fatal if it happens too soon or too late. Omitting even one of these twenty sequential chemical reactions, inserting an unwanted step, or altering the timing of a step would result in death. If even one reaction is missing, all of the other marvelous steps that had previously performed flawlessly would be in vain.
In Michael Behe's excellent book Darwin's Black Box: The Biochemical Challenge to Evolution, this long sequence of reactions is called an irreducibly complex process. If even one step or one chemical reaction is out of place, the whole complex system doesn't work and the organism bleeds to death. These complex chemicals and reactions had to have been created as an intricate, highly integrated unit from the very beginning.
From A Closer Look at the Evidence by Kleiss, August 17.
