Alternate generation

Generation Gen`er*a"tion, n. [OE. generacioun, F. g['e]n['e]ration, fr.L. generatio.] 1. The act of generating or begetting; procreation, as of animals. [1913 Webster]

2. Origination by some process, mathematical, chemical, or vital; production; formation; as, the generation of sounds, of gases, of curves, etc. [1913 Webster]

3. That which is generated or brought forth; progeny; offspiring. [1913 Webster]

4. A single step or stage in the succession of natural descent; a rank or remove in genealogy. Hence: The body of those who are of the same genealogical rank or remove from an ancestor; the mass of beings living at one period; also, the average lifetime of man, or the ordinary period of time at which one rank follows another, or father is succeeded by child, usually assumed to be one third of a century; an age. [1913 Webster]

This is the book of the generations of Adam. --Gen. v. 1. [1913 Webster]

Ye shall remain there [in Babylon] many years, and for a long season, namely, seven generations. --Baruch vi. 3. [1913 Webster]

All generations and ages of the Christian church. --Hooker. [1913 Webster]

5. Race; kind; family; breed; stock. [1913 Webster]

Thy mother's of my generation; what's she, if I be a dog? --Shak. [1913 Webster]

6. (Geom.) The formation or production of any geometrical magnitude, as a line, a surface, a solid, by the motion, in accordance with a mathematical law, of a point or a magnitude; as, the generation of a line or curve by the motion of a point, of a surface by a line, a sphere by a semicircle, etc. [1913 Webster]

7. (Biol.) The aggregate of the functions and phenomene which attend reproduction. [1913 Webster]

Note: There are four modes of generation in the animal kingdom: scissiparity or by fissiparous generation, gemmiparity or by budding, germiparity or by germs, and oviparity or by ova. [1913 Webster]

{Alternate generation} (Biol.), alternation of sexual with asexual generation, in which the products of one process differ from those of the other, -- a form of reproduction common both to animal and vegetable organisms. In the simplest form, the organism arising from sexual generation produces offspiring unlike itself, agamogenetically. These, however, in time acquire reproductive organs, and from their impregnated germs the original parent form is reproduced. In more complicated cases, the first series of organisms produced agamogenetically may give rise to others by a like process, and these in turn to still other generations. Ultimately, however, a generation is formed which develops sexual organs, and the original form is reproduced.

{Spontaneous generation} (Biol.), the fancied production of living organisms without previously existing parents from inorganic matter, or from decomposing organic matter, a notion which at one time had many supporters; abiogenesis. [1913 Webster]