section_path: Subfields/Population and demography
section_name: Population and demography
paragraph_text: Population and demography
  
  Demographers or sociologists of population study the size, composition and change over time of a given population. Demographers study how these characteristics impact, or are impacted by, various social, economic or political systems. The study of population is also closely related to human ecology and environmental sociology, which studies a population's relationship with the surrounding environment and often overlaps with urban or rural sociology. Researchers in this field may study the movement of populations: transportation, migrations, diaspora, etc., which falls into the subfield known as mobilities studies and is closely related to human geography. Demographers may also study spread of disease within a given population or epidemiology.