What are the signs and functions of rotifers, branches, and copepods

It is a general term for a class of heterotrophic invertebrates and chordate larvae that often float in water and cannot make organic matter by themselves.

Rotifers are a group of small, multicellular animals in the phylum Rotunda. General body length 100-300 μm. Most rotifers have three parts : head , torso , and foot ( some are footless , with cilia at the front , resembling a wheel ) . Widely distributed, most live freely, parasitically, individually and in groups. Rotifers in wastewater biological treatment live freely. The body is elongated and divided into head, torso and tail. The head has a rotating wheel composed of 1-2 circles of fiber, shaped like a wheel, so it is called a wheelworm. The roulette wheel is the modal and feeding organ of rotifers, with a chitin chewer in the pharynx. The trunk is rounded and simple, with a broad dorsal abdomen, spines or spines, and a transparent carapace on the outside. At the end of the tail, there are forked toes, and glands inside secrete mucus, which is fixed to other objects. dioecism. Oviparous, mostly parthenogenesis.

Cladocera (Cladocera) is also referred to as "lynx", water, commonly known as red worms, is an invertebrate, crustacean, gill foot suborder, branch horn order. The body is short (body length 0.2 to 1 mm, depending on the specific species, such as large lumps can reach about 4.2 mm), oblong, divided into the head and torso, the lateral flat body segment is not obvious. Except for the bare head, the rest of the body is enclosed in a transparent mesoform shell flap. The head has 2 pairs of obvious antennae, the first pair of antennae is small, and the second pair is particularly developed, can be divided into inner branches and outer branches, can be paddled in water, as a motor organ. 4 to 6 pairs of thoraxes, which can produce water flow when swinging, and have long bristles on them, which can filter food and send it to the mouth.

Copepods belong to the phylum arthropods, crustaceans, and copepod subclasses. It is a small crustacean with a body length of <3 mm, camp planktonic and parasitic life, distributed in the ocean, freshwater or brackish water. Copepods are rapidly active and have relatively long generation cycles, and are less important in aquaculture than rotifers and phylloids. The body is longitudinal and segmented, with no more than 11 segments of the body segment, 1 section of the head, 5 segments of the thorax, and 5 segments of the abdomen. The head has a point of sight, two pairs of antennae, and three pairs of mouthpieces. The thorax has 5 pairs of pectoral feet, the first four pairs are of the same structure, the limb type, the fifth pair is often degenerate, and the sexes are different. The abdomen is unincorporated and has a pair of tail forks at the end and several pinnate bristles behind it. Females often have oocysts in their abdomen. Metamorphosis. i.e., there are arthropods and copepod larvae.

2 Eutrophication: There are also many species that can be used as indicator organisms for water pollution, such as in eutrophicationic water bodies, bare-bellied water, sword water fleas, arm-tailed rotifers and other species of general form dominant population.

3 Toxicity experiments: such as pear-shaped tetramembranous worms, large dips, etc. are used as experimental animals in toxicological tests.

Smaller flora and fauna (mainly plants), mainly algae, bacteria, copepods and some food debris.

There are many types of zooplankton, from low-grade micro-protozoa, coelenterates, ctenophores, rotifers, crustaceans, gastropods, etc., to higher tails, almost every category has permanent representatives, of which a wide variety, large number, and wide distribution of copepods are the most prominent.