What Are Roundworms?
Nematodes are a large group of animals in the Nematoda animal kingdom. About 15,000 species are known, and some estimate 500,000 species. It is widely distributed. Free-living species are found in seawater, freshwater, and soil. Some feed on algae and fungi, and some eat rotifers. Parasitic species are parasitic in humans, animals, and plants, which are more harmful.
- Nematodes are slender and cylindrical, so they are also called roundworms. The body's surface is covered by a thick layer of keratinous membrane, and the protein component is secreted by the epithelium. It is generally divided into three layers: the cortex, the middle layer, and the base layer, which have protective effects. Under the stratum corneum is the syncytium epithelium, that is, the cells of the epithelium have unclear boundaries and have multiple nuclei. The epithelium protrudes inwardly to form a longitudinal ridge, with lateral lines on both sides, and dorsal and ventral lines on the back and ventral surfaces. The nematode has a wide cavity inside it called
- Free-living nematodes breathe through the body surface, and the parasitic species is anaerobic respiration. Excretory organs are in the free-living category, and are completed by 1 to 2 large cells called renettecells, which are called glandular excretory organs. Parasitic nematodes have "H" -shaped excretory tubes, which are specialized formations of protorenal cells, and are called tube-shaped excretory organs. Reproductive organs, males have testes, vas deferens,
- The main features of the nematode phylum are as follows:
- The living environment and life history of nematodes are complex and diverse. In general, they can be divided into three categories: free living, saprophytic and parasitic. The aquatic species generally live in benthic habitats. They have the most marine products, ranging from beaches to extremely deep ocean bottoms. Sometimes they are numerous, becoming the largest number of multicellular animals on the ocean floor. The species of freshwater life exist in It can be seen in a variety of freshwater environments, even in rapids, and the mucus secreted by its tail glands is often fixed on water objects; in hot spring water temperatures of up to 37 ° C, some species can sometimes be seen. Terrestrial species often live in
- The classification system of nematodes. Due to the many species of nematodes, there are about 25,000 recorded species (estimated there are almost 1 million species in total). There are still different opinions on the classification. The following is a list of two scholars:
- Maggenti (1981) Nematode Classification Opinion
- Aphasmida or Adenophorea:
- Subspout (Enoplia)
- Enoplida: eg Enoplus.
- Monochida: For example: Monochus.
- Dorylaimida: For example: Dorylaimus.
- Trichocephalida: such as: whipworm.
- Mermithida: For example: Agamermisdecaudata, Mermis.
- Chromadoria
- Chromadorida: For example: Chromadora.
- Araeolaimida: For example: Plectus.
- Desmocolecida: For example: Desmoscolex.
- Monohysterida: For example: Siphonolaimus.
- Tail sensory class (Phasmida) or tracheid nephron : divided into 3 subclasses
- Rhabditida
- Rhabditia: For example: Rhabditis.
- Strongylida: For example: hookworm.
- Ascaridia: such as: Ascaris.
- Spiruria
- Spiruria: For example: Gnathostoma.
- Diplogasteria
- Diplogasterida: such as: Diplogasterida.
- Tylenchida: such as: Tylenchulus
- Holterman (2006) Taxonomy
- Monomiya Monohysterida
- Spear line Dorylaimea
- Dorylaimia
- Dioctophymida
- Dorylainida
- Cordyceps Mermithida
- Monochida
- Trichocephalida
- Enoplea
- Subspout Enoplia
- Enoplida
- Tracheid
- Rhabditida
- Rhabditda
- Strongylida
- Convolvulus
- Ascaridida
- Camellanida
- Auricularia Oxyurida
- Spirurida
- Diplogasteria
- Diplogasterida
- Tylenchia
- Aphelenchida
- Tylenchida
- Chromadorea
- Chromadoria
- Pharyngea Araeolaimida
- Chromadorida
- Links Desmodorida
- Desmocolecida
- Nematode phylum (scientific name: Nematoda) is
- Nematodes are three germ layers
- Nematodes generally eat
- Nematodes
- Animal parasite
- wild
- There are many species of nematodes, and because of the lack of much knowledge about nematodes, their classification system is still controversial. The Chitwood BG brothers and Chitwood MB proposed an earliest and very influential classification system, which was later modified. This classification system divided nematodes into Apsmidia and Phasmidia. ). It was later renamed Adenophorea and Secrenentea. The tubular nephrons have many common features, including the presence of a tail sensor, which is a pair of sensory organs on both sides of the rear, which also becomes the basis for classification. Because the classification of the tailless sensor subclass is still somewhat different, many subsequent different classifications have also been generated [1] .