Reproduction (also: procreation , breeding , propagation ) - is the process of production by organism of own kind organisms, necessarily associated

Reproduction [Procreation, Breeding, Propagation]

Reproduction (also: procreation, breeding, propagation) — is the process of production by organism of own kind organisms, necessarily associated with an increase in the number of individuals. Reproduction can be asexual and sexual. Asexual reproduction is a characteristic of the most primitive creatures. It is carried out either by dividing the body into pieces, from which offspring develop; or reproduction of offspring by means of special vegetative organs or spores.

Why self-reproduction of living organisms is called procreation? As we know, self-reproduction, i.e. the ability to re-create their own kind, is common to all living beings without exception, and is one of the key features of living matter. After all, any, even the most perfect, organism cannot live indefinitely, and therefore the continuity and heredity of life is provided solely by means of procreation — reproduction of living organisms, that is always associated with an increase in their quantity. What caused such a feature of procreation of living beings? The fact that all organisms propagate by parts or cells of own body, from which subsequently new organisms develop. It is known that quantity of parts are always greater than the whole, therefore, originally the offspring is always more numerous than parents. Taken from http://worldofschool.org

Diagram 1. General scheme of classification of living organisms’ reproduction types

A special meaning is laid in the fact that reproduction occurs with an increase in the number of individuals. Death from disease and accidental causes, low viability or sterility of some individuals, automatically necessitate a larger quantity of offspring than the parents. If we add to this the fact that the animals can exist solely due to eating plants and other animals, and, at the same time, they themselves serve as food for a number of organisms (parasites, pathogenic bacteria, protozoa, and fungi), it is necessary, so that in each new generation the number of descendants would be greater in many times than a number of the parental species. Because otherwise, there may be possible a situation when none of the children will reach sexual mature state and the thread of life will be interrupted. For example, the human population been estimated that for the population remained stable, each woman of childbearing age should have from 2.1 to 2.3 children. If the newborn is less, the population will start to fall, more — to grow.

There are two forms of reproduction of living organisms: asexual and sexual reproduction (diagram 1).

Questions:
  • Define “reproduction”.