Aspects of urban ecology and its evolution in outsides

Thinking about interaction between cities and environments brings about ideas of Urban Ecology, then taking the cities as ecosystems indicates naissance of the Urban Ecology. In 20st century the Urban Ecology comes through the important growing periods from germinating to forming the theoretical system of Urban Ecology. Form the Human Ecology of Chicago School to the studies of MAB Urban Group to the studies of urban ecosystem of LTER networks, all of these embodies in the backgrounds of urbanization and industrialization. The paper combines the backgrounds to purse aspects of study on Urban Ecology in 21st century, summarizes the theoretical contributions of studies and assesses the evolution of Urban Ecology Studies.