\Mon`o*gen"e*sis\, n. [Mono- + genesis.]
1. Oneness of origin; esp. (Biol.), development of all beings
   in the universe from a single cell; -- opposed to
   {polygenesis}. Called also {monism}. --Dana. --Haeckel.

2. (Biol.) That form of reproduction which requires but one
   parent, as in reproduction by fission or in the formation
   of buds, etc., which drop off and form new individuals;
   asexual reproduction. --Haeckel.

3. (Biol.) The direct development of an embryo, without
   metamorphosis, into an organism similar to the parent
   organism; -- opposed to {metagenesis}. --E. van Beneden.