Birth rate and mortality in modern ecology – two defining factors on distribution of natural resources between populations, preservation of a natural biological system in the form of a biocenosis, maintenance of balance of quantity of individuals on territory unit. Often preservation of any given look requires artificial intervention in a biological system.
The birth rate in modern ecology is a total number of new individuals of a certain population. In modern ecology distinguish absolute and specific birth rate. The absolute birth rate is quantity of new individuals concerning unit of time, and specific is quantity of the new individuals carried to their certain number.
The maximum number of the born individuals appears in ideal conditions, but is limited to physiological features of a look. From the moment of the birth to death there are three age periods: prereproductive – the so-called childhood, reproductive - the period of puberty and a physiological opportunity to reproduction, and post-reproductive - an old age.
Mortality is also distinguished as absolute and specific. In this case the speed of decrease in number of individuals comes to light. Diseases, an old age, a lack of food, attack of predators can be the reasons of decrease. Mortality differs on three types: identical at all stages of development, raised at early age or in old age. It is natural that are generally subject to the high mortality of an individual at an early stage of development, so not always possess sufficient functions of protection, immunity and favorable conditions for survival. In general population updates and replaces individuals, thereby adapting to the changing environmental conditions, and also, migration processes. The growing populations are characterized by high birth rate and mass reproduction. In a usual environment this characteristic suits small animals and organisms – for example, to a locust, rodents, weed plants. In the conditions of reserves an opportunity to increase birth rate appears at rare species of animals as favorable conditions and protection are created. If population is reduced, it means that mortality exceeds birth rate and the look gradually dies out.