BIOL 1101 Lecture Notes - Lecture 79: Macronucleus, Micronucleus, Ciliate
Document Summary
This is a diverse group that is named after flattened vesicles (alveoli) under the cell membrane. They are divided into two very different groups, the alveolates and the stramenopiles. The alveolates include the ciliates, the apicomplexans, and a group of flagellates called the dinoflagellates. Cilia are similar to flagella in structure, but they are shorter and tend to beat in synchronous waves, with an oarlike motion. The cilia allow very precise movement such as stopping, pivoting in place, and backing up. Sometimes cilia are fused into stiff organs called cirri, and the ciliate actually walks on the cirri rather than swims. And sometimes, the ciliates are on the ends of contractile stalks. Many invertebrate zoologists have concluded that ciliates have the most complex single cells in the world. Ciliate species range in size from 10 micrometers to 3 mm, about the same ratio of sizes as that between a shrew and a blue whale.