of Charles Darwin. The general approach suggested that "evolution is progressive and leads towards new and better forms in succeeding periods". 'Neofunctionalists' "see the social organization and culture of specific populations as functional adaptations which permit the populations to exploit their environments successfully without exceeding their carrying capacity". 'Processual ecological anthropology' is noted to be new. Studies based on this approach "seek to overcome the split in the second stage of ecological anthropology between excessively short and long time scales". The approach more specifically, examines "shifts and changes in individual and group activities, and they focus on the mechanism by which behavior and external constraints influence each other". One of the leading practitioners within this sub-field of anthropology was Roy Rappaport. He delivered many outstanding works on the relationship between culture and the natural environment in which it grows, especially concerning the role of ritual in the processual relationship between the two. He conducted the majority, if not all, of his fieldwork amongst a group known as the Maring, who inhabit an area in the highlands of Papua New Guinea. Patricia K. Townsend's work highlights the difference between ecological anthropology and environmental anthropology. In her view, some anthropologists use both terms in an interchangeable fashion. She states that, "Ecological anthropology will refer to one particular type of research in environmental anthropology – field studies that describe a single ecosystem including a human population". Studies conducted under this sub-field "frequently deal with a small population of only a few hundred people such as a village or neighbourhood". Cultural Ecology influenced several anthropologists, including L. P. Vidyarthi and his concept of Nature-Man-Spirit (NMS) complex. Globalization effects on the discipline Studies under the discipline are concerned with the ethnoecologies of indigenous populations. Due to various factors associated with globalization, indigenous ethnoecologies are facing increasing challenges such as, "migration, media, and commerce spread people, institutions, information, and technology". "In the face of national and international incentives to exploit and degrade, ethnological systems that once preserved local and regional environments increasingly are ineffective or irrelevant". Threats also exist of "commercial logging, industrial pollution, and the imposition of external management systems" on their local ecosystems. These threats to indigenous ways of life are a familiar occurrence in the field of anthropology. Conrad Phillip Kottak states that, "Today's ecological anthropology , aka environmental anthropology, attempts not only to understand but also to find solutions to environmental problems".