structural:summarization, stylistic:tone
Reproduction

Like all ciliates, Paramecium have a dual nuclear apparatus, consisting of a polyploid macronucleus, and one or more diploid micronuclei. The macronucleus controls non-reproductive cell functions, expressing the genes needed for daily functioning. The micronucleus is the generative, or germline nucleus, containing the genetic material that is passed along from one generation to the next.

Paramecium reproduction is asexual, by binary fission, which has been characterized as "the sole mode of reproduction in ciliates" (conjugation being a sexual phenomenon, not directly resulting in increase of numbers). During fission, the macronucleus splits by a type of amitosis, and the micronuclei undergo mitosis. The cell then divides transversally, and each new cell obtains a copy of the micronucleus and the macronucleus.

Fission may occur spontaneously, in the course of the vegetative cell cycle. Under certain conditions, it may be preceded by self-fertilization (autogamy), or it may immediately follow conjugation, in which Paramecium of compatible mating types fuse temporarily and exchange genetic material.