Like other protozoans, ciliates are unicellular heterotrophs. In some species the cilia are organized into rows or clumps that the organisms use to walk or jump.
Ciliates contain a variety of organelles plus two kinds of nuclei.
The larger type of nucleus, the macronucleus, contains a great deal more DNA than the smaller nucleus, the micronucleus. Although the ciliates typically reproduce asexually, they also exchange genetic information with other ciliate cells by the process of conjugation. During this process two cells unite, the micronuclei undergo meiosis, then pair up and fuse with similar haploid micronuclei from the other organism, mixing the DNA from the two organisms. There are approximately 8,000 species of ciliates. The suctorians are sessile ciliates that suck out the protoplasm of their prey through tentacles.