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The roundworms or nematodes (Phylum Nematoda from Gr. nema, nematos "thread" + ode "like") are one of the most common phyla of animals, with over 20,000 different described species (over 15,000 are parasitic). They are ubiquitous in freshwater, marine, and terrestrial environments, where they often outnumber other animals in both individual and species counts, and are found in locations as diverse as Antarctica and oceanic trenches. Further, there are a great many parasitic forms, including pathogens in most plants and animals, humans included. Only the Arthropoda are more diverse. A roundworm taken from wet soil. ...
Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms (as opposed to folk taxonomy). ...
Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (dicyemids) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ...
Karl Asmund Rudolphi (b. ...
Enoplia are a subclass of the roundworm species. ...
This article needs to be wikified. ...
Subclass Rhabditia, is mostly comprised of parasitic nematodes, though there are some free-living species as well. ...
Phylum (plural: phyla) is a taxon used in the classification of animals, adopted from the Greek phylai the clan-based voting groups in Greek city-states. ...
Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (dicyemids) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ...
The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. ...
A pathogen or infectious agent is a biological agent that causes disease or illness to its host. ...
Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ...
The roundworms were originally named Nematoidea by Rudolphi (1808). They were renamed Nematodes by Burmeister 1837 (as a family; Leuckart 1848 and von Siebold 1848 both promoted them to the rank of order), then Nematoda (Diesing 1861), though Nathan Cobb (1919) argued that they should be called Nemata or Nemates (and in English 'nemas' rather than 'nematodes'). After some confusion which saw the nematodes placed (often together with the horsehair worms, Nematomorpha) as a class or order in various groups such as Aschelminthes, Lankester (1877) definitively promoted them to the level of phylum. Karl Asmund Rudolphi (b. ...
1808 was a leap year starting on Friday (see link for calendar). ...
Karl Moriz Diesing (1800–1867) was an Austrian zoologist, specializing in the study of helminthology. ...
1861 is a common year starting on Tuesday. ...
Nathan Augustus Cobb (30 June 1859 – 4 June 1932) born in Spencer, Massachusetts is known as the father of nematology in the United States. He provided the foundations for nematode taxonomy and described over 1000 different nematode species. ...
1919 (MCMXIX) was a common year starting on Wednesday (see link for calendar). ...
This article needs to be cleaned up to conform to a higher standard of quality. ...
The Aschelminthes (sometimes Aeschelminthes), are an obsolete phylum of pseudocoelomate and other similar animals, including as classes the Nematoda, Rotifera, Gastrotricha, Kinorhyncha, and Nematomorpha, and sometimes the Priapulida and Entoprocta. ...
Ray Lankester, by Leslie Ward, 1905. ...
1877 was a common year starting on Monday (see link for calendar). ...
Morphology
Roundworms are triploblastic protostomes with a complete digestive system. Roundworms have no circulatory or respiratory systems so they use diffusion to breathe and for circulation of substances around their body. They are thin and are round in cross section, though they are actually bilaterally symmetric. Nematodes are one of the simplest animal groups to have a complete digestive system, with a separate orifice for food intake and waste excretion, a pattern followed by all subsequent, more complex animals. The body cavity is a pseudocoel (persistent blastula), which lacks the muscles of coelomate animals used to force food down the digestive tract. Nematodes thus depend on internal/external pressures and body movement to move food through their digestive tracts. The mouth is often surrounded by various flaps or projections used in feeding and sensation. The portion of the body past the anus or cloaca is called the "tail." The epidermis secretes a layered cuticle made of keratin that protects the body from drying out, from digestive juices, or from other harsh environments, as well as in some forms sporting projections such as cilia that aid in locomotion. Although this cuticle allows movement and shape changes via a hydrostatic skeletal system, it is very inelastic so does not allow the volume of the worm to increase. Therefore, as the worm grows, it has to moult and form new cuticles. The cuticles don't allow volume to increase so as to keep hydrostatic pressure inside the organism very high. For this reason, the roundworms do not possess circular muscles (just longitudinal ones) as they're not required. This hydrostatic pressure is the reason the roundworms are round. Triploblastic is a condition of the ovum in which there are three primary germinal layers: the ectoderm, mesoderm, and endoderm. ...
Protostomes (from the Greek: first the mouth) are a taxon of animals. ...
For the Physics term GUT, please refer to Grand unification theory The gastrointestinal or digestive tract, also referred to as the GI tract or the alimentary canal or the gut, is the system of organs within multicellular animals which takes in food, digests it to extract energy and nutrients, and...
Illustration of the different types of symmetry of Life Forms On Earth. ...
By the broadest definition, a body cavity is any fluid filled space in a multicellular organism. ...
Blastulation. ...
Male Human Anatomy This article is about the bodily orifice. ...
In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, urinary, and genital tracts of certain animal species. ...
Microscopy of keratin filaments inside cells. ...
A hydrostatic skeleton is one in which the bodys shape and/or function is maintained by an incompressible fluid such as blood or hemolymph. ...
Ecdysis is the molting of the cuticula in arthropods and related groups (Ecdysozoa). ...
Most free-living nematodes are microscopic, though a few parasitic forms can grow to several meters in length. There are no circular muscles, so the body can only undulate from side to side. Contact with solid objects is necessary for locomotion; its thrashing motions vary from mostly to completely ineffective at swimming. A top-down view of skeletal muscle Muscle is the contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ...
Roundworms generally eat bacteria, algae, fungi and protozoans, although some are filter feeders. Excretion is through a separate excretory pore. ‹ The template below has been proposed for deletion. ...
A seaweed (Laurencia) up close: the branches are multicellular and only about 1 mm thick. ...
Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ...
Protozoa (in Greek protos = first and zoon = animal) are single-celled creatures with nuclei that show some characteristics usually associated with animals, most notably mobility and heterotrophy. ...
Filter feeders (also known as suspension feeders) are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized structure, such as the baleen of baleen whales. ...
Excretion is the biological process by which an organism chemically separates waste products from its body. ...
Reproduction is usually sexual. Males are usually smaller than females (often very much smaller) and often have a characteristically bent tail for holding the female for copulation. During copulation, one or more chitinized spicules move out of the cloaca and are inserted into genital pore of the female. Amoeboid sperm crawl along the spicule into the female worm. It has been suggested that Mating be merged into this article or section. ...
Structure of chitin molecule In biology, chitin (pronounced keye-tin) is one of the main components in the cell walls of fungi, the exoskeletons of insects and other arthropods, and in some other animals. ...
Spicules are skeletal structures that appear in some types of sponges. ...
Amoeba (Chaos diffluens) Foraminiferan (Ammonia tepida) Heliozoan (Actinophrys sol) Amoeboids are cells that move or feed by means of temporary projections, called pseudopods (false feet). ...
The signifier sperm can refer to: (mass noun, from Greek sperma = seed) a substance which consists of spermatozoa and which is a component of semen (mass noun) semen itself (informally, count noun with plural sperm or sperms) a single spermatozoon (= sperm cell) sperma ceti (Latin ceti, genitive of cetus = whale...
Eggs may be embryonated or unembryonated when passed by the female, meaning that their fertilized eggs may not yet be developed. In free-living roundworms, the eggs hatch into larva, which eventually grow into adults; in parasitic roundworms, the life cycle is often much more complicated.
Roundworms have a simple nervous system, with a main nerve cord running along the ventral side. Sensory structures at the anterior end are called amphids, while sensory structures at the posterior end are called phasmids. ...
Free-living species In free-living species, development usually consists of four molts of the cuticle during growth. Different species feed on materials as varied as algae, fungi, small animals, fecal matter, dead organisms and living tissues. Free-living marine nematodes are important and abundant members of the meiobenthos. One roundworm of note is Caenorhabditis elegans, which lives in the soil and has found much use as a model organism. C. elegans has had its entire genome sequenced, as well as the developmental fate of every cell determined, and every neuron mapped. Introduction Meiofauna are small benthic invertebrates that live in both marine and fresh water environments. ...
Binomial name Caenorhabditis elegans Maupas, 1900 Caenorhabditis elegans (pronounced see-no-rab-DYE-tis) is a free-living nematode (one of the roundworms), about 1 mm in length, which lives in a temperate soil environment. ...
A model organism is a species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. ...
Parasitic species Parasitic forms often have quite complicated life cycles, moving between several different hosts or locations in the host's body. Infection occurs variously by eating uncooked meat with larvae in it, by entrance into unprotected cuts or directly through the skin, by transfer via blood-sucking insects, and so forth. An Anopheles stephensi mosquito obtaining a blood meal from a human host through its pointed proboscis. ...
Nematodes commonly parasitic on humans include whipworms, hookworms, pinworms, ascarids, and filarids. The species Trichinella spiralis, commonly known as the trichina worm, occurs in rats, pigs, and humans, and is responsible for the disease trichinosis. Baylisascaris usually infests wild animals but can be deadly to humans as well. Haemonchus contortus is one of the most abundant infectious agents in sheep around the world, causing great economic damage to sheep farms. In contrast, entomopathogenic nematodes parasitize insects and are considered by humans to be beneficial. Binomial name Trichuris trichiura (Linnaeus, 1771) The human Whipworm (Trichuris trichiura or Trichocephalus trichiuris), is a roundworm, which causes trichuriasis when it infects a human large intestine. ...
The hookworm is a parasite that lives in the small intestine of its host, which may be a mammal such as a dog, cat, or human. ...
The pinworm (Genus Enterobius) is a parasitic roundworm of the phylum Nematoda. ...
Binomial name Ascaris lumbricoides Ascaris lumbricoides is a human parasitic roundworm, which causes ascariasis, and occurs in roughly one billion people worldwide, including four million in the US. is the largest nematode (roundworm) which parasitizes the human intestine. ...
Trichinosis, also called trichinellosis, is a parasitic disease caused by eating raw or undercooked pork and wild game products infected with the larvae of a species of roundworm Trichinella spiralis, commonly called the trichina worm. ...
Trichinosis, also called trichinellosis, is a parasitic disease caused by eating raw or undercooked pork and wild game products infected with the larvae of a species of roundworm Trichinella spiralis, commonly called the trichina worm. ...
Baylisascaris is a genus of roundworms that infest more than fifty animal species. ...
Haemonchus contortus, also called Barbers pole worm because of the red/white striped occurrence of the female, is a roundworm that can infect goats and sheep. ...
Nematodes emerging from a wax moth cadaver. ...
One form of nematode is entirely dependent upon the wasps which are the sole source of fig fertilization. They prey upon the wasps, riding them from the ripe fig of the wasp's birth to the fig flower of its death, where they kill the wasp, and their offspring await the birth of the next generation of wasps as the fig ripens. Species About 800, including: Ficus altissima Ficus americana Ficus aurea Ficus benghalensis- Indian Banyan Ficus benjamina- Weeping Fig Ficus broadwayi Ficus carica- Common Fig Ficus citrifolia Ficus coronata Ficus drupacea Ficus elastica Ficus godeffroyi Ficus grenadensis Ficus hartii Ficus lyrata Ficus macbrideii Ficus macrophylla- Moreton Bay Fig Ficus microcarpa- Chinese...
Plant parasitic nematodes include several groups causing severe crop losses. The most common genera are: Aphelenchoides (foliar nematodes), Meloidogyne (root-knot nematodes), Heterodera, Globodera (cyst nematodes), Nacobbus, Pratylenchus (lesion nematodes), Ditylenchus, Xiphinema, Longidorus, Trichodorus. Several phytoparasitic nematode species cause histological damages to roots, including the formation of visible galls (Meloidogyne) which are useful characters for their diagnostic in the field. Some nematode species transmit plant viruses through their feeding activity on roots. One of them is Xiphinema index, vector of GFLV (Grapevine Fanleaf Virus), an important disease of grapes.
Other nematodes attack bark and forest trees. The most important representative of this group is Bursaphelenchus xylophilus, the pine wood nematode, present in Asia and America and recently discovered in Europe.
Gardening Ironically, nematodes are both a nemesis and a hero for gardeners.
From a gardening perspective, there are two categories of nematode, predatory ones which will kill garden pests like cutworms, and pest nematodes like the rootknot nematode, which attack garden plants. The term cutworm is used for the larvae of many species of moth. ...
Predatory nematodes can be bred by soaking a specific recipe of leaves and other detrius in water, in a dark, cool place, and can even be purchased as an organic form of pest control.
Phylogeny Current studies suggest that roundworms (nematodes) are related to the arthropods and priapulids in a newly recognized group, the Ecdysozoa (molting animals). Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ...
Priapulida (priapulid worms, or penis worms) are a phylum of marine worms with an extensible spiny proboscis. ...
The Ecdysozoa are a large group of protostomian animals, erected by Aguinaldo in 1997 primarily based on 18s rRNA data. ...
References in Popular Culture Nickelodeon (Nick for short, launched April 1, 1979 as The Pinwheel Network) is a cable TV network primarily for children and pre-teens, but also features shows for teenagers in TEENick. ...
Doug is the short form of the name Douglas Doug was an American animated television series on Nickelodeon and is the first Nicktoon ever made, starring a 12-year-old named Doug. ...
SpongeBob SquarePants is a popular American animated television series shown on Nickelodeon, YTV, and Nicktoons Network created by marine biologist and animator, Stephen Hillenburg. ...
Home Sweet Pineapple is a SpongeBob SquarePants episode from season 1 Spoiler warning: Brief summary: When hungry/thirsty nematodes eat/drink SpongeBobs pineapple house, he is forced to find a new home. ...
See also Toxocariasis is a parasitic infection with the dog or cat roundworm, Toxocara canis or Toxocara cati, respectively. ...
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