1. ROTIFERS

2. Characteristics
Phylum Rotifera (rota=wheel, fera= to carry). Approximately species.
Rotifers are small animals. They range from 40 µm to 3 mm in length but most are 100 to 500 µm.
The name is derived from the characteristic ciliated crown or corona. When the cilia are beating, it gives the impression of rotating wheels.
Their outer coat looks like clear glass
Sometimes the glassy outer coat are covered with spines or spikes
They have a ring of hair at their head end called cilia which beat in a wave making currents to bring in food particles

3. HABITAT
They live in freshwater some of the species live in brackish water or damp soils or mosses. Only a few species are marine. Some lie on the body of another animal or are parasitic.
Some are attached to plant stems while others swim through the water
They live in moist sands along the shore and in the gravel of aquarium tanks
Some can endure long periods of desiccation, during which they resemble grains of sand. Once water arrives, they revive. Some can survive for up to 4 years of desiccation.

4. FEEDING
They eat algae debris and other protists, bacteria, and even other rotifers

5. Rotifer Anatomy
The body of a rotifer is composed of a head bearing a ciliated corona, a trunk, and a posterior tail or foot.
Internal organs include a brain, eyespots, mouth, stomach, intestine, and anus.
Excretory system contains flame cells like flatworms.

6. REPRODUCTION
Rotifers are dioecious. Males can be smaller than females.
Some species of rotifers only sexual reproduction, some only use asexual reproduction and some have both sexual and asexual reproduction
In the class Bdelloidea, males are entirely unknown. They use parthenogenesis for reproduction. Parthenogenesis is an asexual reproduction pattern in which all members are female. They produce eggs which develop unfertilized. This is basically cloning the mother. The daughters are genetically identical to the mother
In the class Monogononta, males seem to occur only for a few weeks of the year. They can use parthenogenesis or sexual reproduction.
In the class Seisonidea, females produce haploid eggs that must be fertilized and develop into either males or females.

7. Rotifer Classes:
Class Seisonidea: Marine; elongated rotifers. Sexes similar in size and form. Can live on the gills of a crustacean (Nebalia)
Class Bdelloidea: Swimming or creeping forms. Males are unknown. Reproduce by parthenogenesis.
Class Monogononta: Swimming or sessile forms. Males are reduced in size. Eggs are produced in three types (amictic mictic, and dormant).