John Todd's living machines is based on biological diversity: "One needs to have everything from the ancient creatures, such as the early anaerobic phototropic bacteria, to the vertebrates for these systems to run for any length of time" (The Bioneers, pg. 21). Despite all the bacteria and living items in John Todd's system, the water which comes out of it is sanitary and is cleaner than most other drinking waters. All the bacteria in the machine work together to clean the water and actually feed off all the harmful-to-humans chemicals: "Like an inanimate machine a living machine does work, but it does so with the intelligence of three and a half billion years of experimentation by life forms. A living machine is a consciously directed ecosystem aimed toward alleviating a human-caused problem. It is very unusual in that the human being in its partnership with the living machine is the junior partner, because the intelligence in the system is contained within the organisms themselves. They know how to self-design, self-replicate, and self-repair. It is possible to create a living machine that will last for hundreds or thousands of years, and to do so in a manner that need not exploit the natural or wild world which sustains all of us" (The Bioneers, pg 21). Even though this system sounds complicated, the system cleans and works itself and doesn't require much maintenance. The problem of the depletion of sanitary drinking water has plagued mankind for centuries. Many solutions have been attempted with more and more chemicals being added to the water in attempts to kill all the bacteria and all the dirt but to their surprise, caused more and powerful diseases itself. The one solution that actually works the best was founded by John Todd through his Alternative Greenhouse Effect or living machines, which consists of bacteria and living organisms to clean the water and is also considered one of the simplest ways of cleaning water.