Studies dating from the early 1900's provide ample information to show that biological diversity is the only sustainable design for sustainable living. A single organism or a small group of organisms cannot be held responsible for sustainable living. This is where modern farming methods have got it wrong, and are therefore struggling with multiple problems like pests, low crop yield and high investment in farming techniques.
Permaculture came about due to the pressing realization by certain groups of people that the Earth is reaching its physical limits. Our ever-increasing appetite for energy is depleting the natural resources available to us. The depressing thought of Earth stripped of all her resources led to a silent yet strong revolution that voiced the cry for new methods of sustainable designs for sustainable living - of all organisms, not just humans.
Permaculture, according to Andrew Faust who has been teaching permaculture design for more than 17 years, may be described as increasing ecological health to meet human needs. Faust, like other permaculture practitioners, advocates low-tech, passive farming methods as opposed to the high-tech, "energy-hog" infrastructure that is being followed by farmers today.
Permaculture or 'permanent culture' builds on the sustainable design for sustainable living provided by Mother Nature herself. A complex network of interconnected species form simultaneous connections with different organisms and the total system is a synergistic whole that is nurtured by these interconnections. As the number of interconnections increases, so also does the sustainability of the system. For instance, in a farmland, the farmer uses pesticides to control weeds.
Due to the above reasons, permaculture farming is much less labor intensive than a modern farm. A natural forest contains a number of layers of elements in it. From low lying plants to creepers, shrubs and tall trees, different elements populate it. The production of required material from such an ecosystem would outweigh the production of the same material in a modern farm. This is because the former requires little by way of maintenance while the modern farm needs ploughing, seeding, manuring, cultivating, weeding and so on. The energy required to tend to a modern farm requires different kinds of inputs from fossil fuel to more conventional forms of energy. However, if we could coax the natural forest to produce the crops that we want, the effort and the energy required would be much lesser. This is the sustainable design found in nature that we can depend on for sustainable living.