1911 Encyclopædia Britannica/Generation
GENERATION (from Lat. generare, to beget, procreate; genus, stock, race), the act of procreation or begetting, hence any one of the various methods by which plants, animals or substances are produced. As applied to the result of procreation, “generation” is used of the offspring of the same parents, taken as one degree in descent from a common ancestor, or, widely, of the body of living persons born at or near the same time; thus the word is also used of the age or period of a generation, usually taken as about thirty years, or three generations to a century. As a term in biology or physiology, generation is synonymous with the Gr. βιογένεσις and the Ger. Zeugung, and may comprehend the whole history of the first origin and continued reproduction of living bodies, whether plants or animals; but it is frequently restricted to the sexual reproduction of animals. The subject may be divided into the following branches, viz.: (1) the first origin of life and living beings, (2) non-sexual or agamic reproduction, and (3) gamic or sexual reproduction. For the first two of these topics see Abiogenesis, Biogenesis and Biology; for the third and more extensive division, including (1) the formation and fecundation of the ovum, and (2) the development of the embryo in different animals, see Reproduction and Embryology.