The article explores the origins of the theory of ecosystem services, its causes, and essential features. We have identified the problem of terminological pluralism with regard to ecosystem services. Therefore, the definition of ecosystem services remains debatable till present. The authors have justified the conceptual boundaries between “ecosystem services” and “ecosystem functions”, which helps to make the following conclusion: “ecosystem functions” are valuable for ensuring the integrity of ecosystems, as well as in the narrower sense – for human life; in the latter case, we speak of the “ecosystem services” for society and individuals. The article explores the evolution and makes a detailed analysis of the existing classifications of ecosystem services and ecosystem functions using both domestic and foreign studies in the field of environmental economics. We have concluded that at the present day, the most complete definition and classification of ecosystem services are presented in the research within the project of “Millennium Ecosystem Assessment”, 2005. This approach allows identifying the sources of ecosystem services and their relationship with both the processes occurring in the biosphere and their impact on human economic activity. In addition, this classification is used in numerous studies and it is useful when applying the concept of total economic value for the purpose of economic evaluation of ecosystems’ natural resources and the natural-resources potential of the territory as a consequence. Given the experience of the analyzed classification of ecosystem services, we offer the authors’ list of ecosystem services based on the classification of the “Millennium Ecosystem Assessment”, 2005, in which the providing services are “the products obtained from ecosystems”. According to the authors’ interpretation, these services are natural resources received from ecosystems (biota) and environmental conditions (abiotic component): mineral resources, land resources, water resources, and biological resources (animals, plants).