An economy comprising two very different systems, and found in many developing countries where an advanced economy co-exists with a traditional economy and the two have very little contact with each other. In many less developed countries, a subsistence system operates side by side with, but quite independently of, cash cropping. This is a result of uneven development. The concept also applies to more developed economies, where core regions with large-scale, thriving industries compare with their less developed peripheries: northern Italy and the Mezzogiorno are often quoted as an example.
Certain geographers dislike the concept, arguing that it is too simplistic; why should there be only two elements, and are they necessarily completely distinct?




