Demography is the statistical study of human
Humans are the only living species in the Homo genus...

A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...

. It can be a very general science that can be applied to any kind of dynamic human population, that is, one that changes over time or space (see population dynamics
Population dynamics
Population dynamics is the branch of life sciences that studies short-term and long-term changes in the size and age composition of populations, and the biological and environmental processes influencing those changes...

). It encompasses the study of the size, structure and distribution of these populations, and spatial and/or temporal changes in them in response to birth
Birth is the act or process of bearing or bringing forth offspring. The offspring is brought forth from the mother. The time of human birth is defined as the time at which the fetus comes out of the mother's womb into the world...

, migration, aging  and death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....


Demographic analysis
Demographic analysis
Demographic analysis includes the sets of methods that allow us to measure the dimensions and dynamics of populations. These methods have primarily been developed to study human populations, but are extended to a variety of areas where researchers want to know how populations of social actors can...

 can be applied to whole societies or to groups defined by criteria such as education
Education in its broadest, general sense is the means through which the aims and habits of a group of people lives on from one generation to the next. Generally, it occurs through any experience that has a formative effect on the way one thinks, feels, or acts...

, nationality
Nationality is membership of a nation or sovereign state, usually determined by their citizenship, but sometimes by ethnicity or place of residence, or based on their sense of national identity....

, religion
Religion is a collection of cultural systems, belief systems, and worldviews that establishes symbols that relate humanity to spirituality and, sometimes, to moral values. Many religions have narratives, symbols, traditions and sacred histories that are intended to give meaning to life or to...

 and ethnicity.