ABSTRACT
The human population worldwide has always been increasing except for short-term falls in the 14th and 17th centuries. These falls were mainly due to pandemics caused by ‘black death’ and plague. It is also predicted that the population will continue to increase until about 2050. Attempts to model population dynamics can be traced back to the late 18th century when the Malthusian exponential growth theory was introduced. Although it has been modified, refuted, or superseded by the works of subsequent researchers, it still stands as the backbone of many population dynamics models. Division of cells is by binary fission, mitosis, and meiosis. Prokaryotic cells that lack a nucleus divide by binary fission. Eukaryotic cells divide by mitosis or meiosis. The growth rate of cells during the exponential growth phase is expressed by the term ‘generation time’, which is the time taken to double the population under standard nutritional conditions.
