Comment So help the new guy out (Score 1) 1306
I grabbed the meat of their transcript so we don't need to
The bombardier beetle has a powerful and complex system for protecting himself from enemies. Glands within the beetle produce a mixture of two hydroquinone compounds and hydrogen peroxide. These chemicals must be held in separate chambers, because when they come into contact with each other they react. When the beetle is threatened, the chemicals are mixed in a third chamber where a third chemical is added and an explosive reaction takes place. This reaction forces the caustic solution out through a special "nozzle." The beetle is skilled in aiming this nozzle at its enemy.
If this system is missing any of its parts, it is more than worthless to the beetle; the chemicals alone are very dangerous. So this sophisticated defense system could not have evolved in stages. Imagine the poor beetle who evolved the ability to produce the chemicals but hadn't yet evolved the right chambers to mix them without blowing itself up. The first time he became alarmed, poof!-no more beetle at all!