Rotifers are a group of microscopic, multicellular animals belonging to the phylum Rotifera. They are commonly referred to as wheel animals due to the presence of a circular arrangement of cilia at their anterior end, which resembles rotating wheels. Rotifers inhabit freshwater environments such as ponds, lakes, and rivers, as well as in soil, damp mosses, and temporary freshwater bodies. Some species can also be found in marine and brackish water habitats.
These organisms typically range in size from 50 micrometers to a few millimeters, making them visible under a microscope. They are characterized by a unique body structure comprising a cylindrical or elongated torso, a retractable head bearing a mouth surrounded by ciliary feeding structures, and a posterior tail-like structure called the foot. The body may also possess additional appendages, such as spines or bristles.
Rotifers are filter-feeders, using their cilia to create water currents that draw in microscopic food particles into their mouths. Their diet includes bacteria, algae, protozoa, and organic detritus. Despite their small size, rotifers play important roles in aquatic ecosystems as grazers, consuming large quantities of microbial communities and organic matter, thereby influencing nutrient cycling and water quality.
Rotifers have remarkable reproductive capabilities, with many species capable of parthenogenesis, a form of asexual reproduction where unfertilized eggs develop into viable offspring. Some species, however, reproduce sexually. Their ability to adapt to a range of habitats and withstand harsh environmental conditions has contributed to their success and diversity, with over 2,000 identified species known to date.
