"Urbanism is analogous to life in many ways. That is to say, a city is not a living creature, a city is like a living creature in useful ways. Types of settlements are similar to distinct species. A farming hamlet, for example, is far different from a metropolitan borough on many counts. They have far different habitats, food sources, life cycles, metabolic rates, waste materials, and appearances. So if types of settlements are like distinct species, then a particular city, town, village, or hamlet is like a single creature, and individual buildings within the city, town, village, or hamlet is like individual cells within the creature."