During the first urban revolution, from about 8000 to 2000 B.C.E. people moved into cities for the first time.
The second urban revolution occurred from around 1700 to 1950 and coincided with the Industrial Revolution. Modern cities developed and gained prominence as commerce replaced farming as the main way to make a living.
Today, the third urban revolution is still underway.
One important distinction between rural and urban areas is not how many people live there but how people make a living. Most people in a rural area have occupations that involve harvesting natural resources- such as fishing, logging, and farming. In urban areas, most people have jobs that are not directly connected with natural resources.
Urban ecologists study these processes, trends, and patterns in the context of four variables: population, organization, environment, and technology; they use the acronym POET to refer to these variables.
The four variables (POET) do not function independently of one another, they are interrelated and interact much like the parts of natural ecosystems.
Urbanization has potential to provide tangible environmental benefits that in many cases outweigh the negative aspects. A solution to urban growth is compact development, which uses land efficiently. Also in many compact development areas the use of a motor vehicles is replaced with walking, cycling, or public transportation.
COMPACT DEVELOPMENT : the design of cities in which tall, multiple-unit residential buildings are close to shopping and jobs, and all are connected by public transportation.
SUBURAN SPRAWL : a patchwork of vacant and developed tracts around the edges of cities; contains a low population density.
Urbanization and its accompanying suburban sprawl affect land use and have generated a new series of concerns. During the 1940’s and 1950’s, jobs and homes began to move from urban centers to the suburbs, cutting deeper into the surrounding rural land and causing environmental problems such as loss of wetlands, loss of biological habitat, air pollution, and water pollution.