Ciliates can reproduce both sexually and asexually.
Slipper ciliates usually reproduce asexually – by dividing in two. However, unlike flagellates, ciliates divide across the body: a constriction is formed in the middle of the ciliate’s body and, thus, two cells are formed from one cell.
Infusoria-shoes are divided once or twice a day.
The nuclei are divided into two parts, and in each new ciliate there is one large and one small nucleus. Each of the two daughter ciliates receives part of the organelles, while the others are formed anew.
The sexual process of the infusorian shoe is called conjugation. It takes place in several stages.
Conjugation is the sexual process of unicellular animals, in which they exchange their hereditary material.
Stages of conjugation of ciliates
1. Approximation of two ciliates (MI – micronucleus; MA – macronucleus) and the formation of a cytoplasmic bridge between them.
2. The first division of a micronucleus (as a result, the formation of two nuclei).
3. The second division of the micronucleus (as a result, the formation of four nuclei).
4. Three of the four formed micronuclei die. The macronucleus also dies.
5. The third division of the micronucleus (as a result, the formation of two nuclei).
6. Exchange of nuclei (one of the two formed nuclei passes to the cell of another ciliate).
7. Fusion of two new micronuclei into one nucleus.
8. Fission of the nucleus in two.
9. Of the two available nuclei, one becomes a macronucleus, the other a micronucleus.
The biological significance of conjugation lies in the renewal of genetic material and the possible appearance of new traits.