Continuous multiplication by binary fission is interrupted by conjugation as it is necessary for the survival and rejuvenation of the race.Д¬onjugation inducing factors:The following are the factors which induce conjugation, It is a temporary union of two individuals of same species for mutual exchange of genetic materials. In Paramecium, Conjugation is a form of sexual reproduction. The whole process is completed within 2 hours and may occur one to four times a day. One contractile vacuole goes to protor and another to opisthe. Oral groove and cytopharynx are newly formed in both the daughters. They are of equal size and contain a complete set of cell organelles as in parents. In this way, two daughter-Paramecia are produced.Дaughter from anterior end is called protor and another daughter from posterior end is called opisthe. At the same time, the constriction develops at the middle part of the body which divides cytoplasm into two equal parts. After division, they move towards the opposite end. Macronucleus divides by amitosis and micronucleus divides by mitosis. Paramecium stops feeding before initiating binary fission and then its oral groove disappears. Nuclear division is followed by the cytoplasmic division. Division occurs at the right angle to the longitudinal axis of the body. A fully grown Paramecium is divided into two daughter individuals. It is a common method of reproduction in Paramecium which occurs during favorable condition. ASEXUAL REPRODUCTION: BINARY FISSIONД«inary fission occurs in transverse fashion in Paramecium. Whereas, binary fission is an asexual reproduction process in which nuclear organization does not occur. A new macronucleus is produced by the following processes: The new macronucleus has rejuvenating effect on the clone. Replacement of the imbalanced macronucleus thus is very important. If the nuclear organization fails to occur, the asexual clone dies. For example, it has been shown that some species of paramecium can pass through only about 320-350 continuous asexual binary fissions. This imbalance reduces the vigors and vitality of the clone. Due to repeated binary fission, genic balance of macronucleus is disturbed. In binary fission the macronucleus divides by amitosis in which chromosomes are distributed at random to the daughter macronuclei. The degeneration of old macronucleus and the formation of the new one by fusion of micronuclei is called as nuclear organization.

Example of binary fission