Conjugation - Patterns of Sexual Reproduction

Conjugation is a temporary union among two individuals of the same species, during which the original macronucleus disintegrates, a new macronucleus is built from micronucleus, and the conjugants exchange nuclear material. The male nucleus of one moves over to the opposed individual and fuses with its stationary female nucleus. The procedure is reciprocal and the conjugants separate. This is followed by fission of the conjugants. Paramecium is a good instance. Conjugation in such cases gives a kind of rejuvenation. Repeated asexual reproduction by fission through some 350 or much more generations leads to onset of senility and weakens the race which may otherwise die out.