Definition of knell. 1  transitive verb. : 2  to summon or announce by or as if by a knell. 3  intransitive verb. 4  1 : to ring especially for a death, funeral, or disaster : toll. 5  2 : to sound in an ominous manner or with an ominous effect.
For the journal, see Demography (journal) . Demography is the statistical study of populations, including of human beings. As a very general science, it can analyze any kind of dynamic living population, i.e., one that changes over time or space (see population dynamics).
Demography is the study of these changes. Ecologists use demographic analysis to predict the growth of a population. Birth rate, death rate, immigration and emigration can be used to determine the growth rate of the population in a given period of time. This data can also be used to develop plans to protect endangered species. Survivorship Curves