Although population of some animals is also studied, the population of human beings is most extensively studied. Whenever the word population is used, it connotes the human population. Population is one of the most important subjects known for having large scale ramifications on economic, social, environmental and developmental scenario of a country.
Population is defined as the total number of individuals of a species present in a particular area. (For e.g., a country or a state or a city).
Each of the derived parameter in the study of population has specific significance.
It is the most important parameter indicating the pressure of population on land, water and other resources. Usually, higher population density (expressed as number of people (square kilometers) is found in urban areas than in rural areas. Regional disparities of density of population helps the government to plan about regional priority development. Concentrated population in some parts -as indicated by higher density - demands, creation of more facilities such as transport, electricity, housing, sanitation etc. in such parts of country.
Percentage of adult population is an important indicator for growth of population. A part of adult population may be reproductively active - which forms the basis of projections of birth rate and growth rate. Total adult population and classified data on adult population - sex wise, education wise, habitation wise (rural and urban) can lead to many meaningful inferences in the fields of employment opportunities, women work force, urban habitations, etc.
Population of a country should grow reasonably to match with growth in its gross domestic product to maintain the existing standard of living. Reducing growth or negative growth in population may be desirable if the standard of living should increase by more favourable per capita distribution of wealth.
A British economist Malthus'(1778) proposed a theory that population grows at geometric proportion and after the imbalance between population and resources is set in, population is automatically checked by natural disasters (like famine, epidemic, disease, earthquake, flood) called positive checks.
It is defined as an inherent capacity of females to conceive and deliver babies in their reproductive life. It is also called as fecundity. This varies largely from individual to individual. It is usually studied on mean basis for the entire population. The study of biotic potential is useful to understand the maximum ceiling to which the population can grow. It is also useful to decide what percent of biotic potential is necessary to be exploited to achieve the expected growth rate. All birth control measures are aimed at ways and means to under utilize the biotic potential, although they cannot reduce the biotic potential itself.
India is the best country to study the consequences of over population. Geometric growth in population has pushed our country into population explosion leading to number of serious consequences.
Reproductive health refers to health issues connected with reproduction. The health of mother during pregnancy (also called pre - natal) and after child birth (also called antenatal) and health of child are included in reproductive health.
Adolescence refers to an age between 8 to 16 years. It is a stage of human development between childhood and adulthood.
Most problems of adolescence are due to failure in understanding the anatomical, morphological and psychological changes expected during adolescence.
Adolescent problems may lead to sex related complications such as - contract with AIDS (curiosity about sex, ignorance of birth control measures may lead to such consequence) or other STD (Sexually Transmitted Diseases).
Except human beings, no other animal can have mental disorders and addiction problems.
It is a disease characterised by loss of perceptions of realities of life, may or may not be associated with brain dysfunctioning or nervous disorders. The psychic patients are generally not aware of their disease and usually refuse to undergo treatment - as they invariably perceive that they are normally behaved and others are mentally ill.
Any one or more causes listed below can cause mental illness of varying proportion and manifestations.
Addiction is defined as a habit forming dependence of a person on some harmful materials such as tobacco, alcohol, drugs (psychotropic). The repetitive dependence factor in use of these materials will make a person insensitive to these intoxicants / narcotics. This further promotes one to use overdoses of these materials to obtain so called intoxication. So, use of such material becomes a habit and will be a part of daily routines of addicts. The process is called addiction and person in question is called addict. Addiction is a social evil than a physiological / anatomical disorder.
Community health refers to health issues concerning a common group of people. It is different from individual health issues in the sense that symptoms, control measures are community oriented. Large part of community health deals with preventive medicines as well as preventive care. Preventive care may include many community facilities involving sanitation, environmental pollution, educating about public hygiene etc.
Asia has 60% of global population and continues to dominate the global population in next 50 years.