Arachnid
"Arachnida" from Ernst Haeckel's Kunstformen der Natur, 1904
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Subphylum: Chelicerata Class: Arachnida Cuvier, 1812
Extant orders
Acarina Amblypygi Araneae Opiliones Palpigradi Pseudoscorpionida Ricinulei Schizomida Scorpiones Solifugae Uropygi

Arachnids are a class (Arachnida) of joint-legged invertebrate animals in the subphylum Chelicerata. Ernst Heinrich Philipp August Haeckel ( February 16, 1834 — August 9, 1919)also written von Haeckel, was an eminent German Kunstformen der Natur ( German: Art Forms of Nature) is a book of lithographic and Autotype prints by German biologist Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " The subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda including the Arachnids Horseshoe crabs and related forms Baron Georges Léopold Chrétien Frédéric Dagobert Cuvier ( August 23 1769 &ndash May 13, 1832) was a French naturalist Acarina or Acari are a Taxon of Arachnids that contains Mites and Ticks The diversity of the Acari is extraordinary and its Amblypygi is an order of Invertebrate Animals belonging to the class Arachnida in the Subphylum Chelicerata of the Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings Harvestmen are eight-legged Invertebrate animals belonging to the order Opiliones (formerly Phalangida) in the class Arachnida in the subphylum A palpigrade, commonly known as a microwhip scorpion, is an invertebrate animal belonging to the order Palpigradi in the class Arachnida, in the subphylum A pseudoscorpion, (also known as a false scorpion or book scorpion) is an Arachnid belonging to the order Pseudoscorpionida, also known The Order Ricinulei is a group of Arachnids known as hooded tickspiders. Schizomida is an order of Arachnids superficially resembling spiders and generally less than 5mm in length Scorpions are eight-legged Carnivorous Arthropods They are members of the order Scorpiones within the class Arachnida. Solifugae is an order of Arachnida containing more than 1000 described Species in about 140 genera. A uropygid, commonly known as a whip scorpion, is an invertebrate animal belonging to the former order "Uropygi" in the class Arachnida, Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " An invertebrate is an Animal lacking a Vertebral column. The group includes 98% of all animal Species — all animals except those in the Chordate The subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda including the Arachnids Horseshoe crabs and related forms The term arachnid is from the Greek word άράχνη or arachne, meaning spider,^[1] and also referring to the mythological figure Arachne. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Greek mythology is the body of stories belonging to the ancient Greeks concerning their gods and Heroes the nature of the world and the origins and significance Arachne was a great mortal weaver She boasted that her skill was greater than that of Athena the goddess of crafts which resulted in a contest between her and the goddess

Arachnids are chiefly terrestrial arthropods, but are also found in freshwater and, with the exception of the pelagic zone, in all marine environments. Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " They comprise over 100,000 named species, including spiders, scorpions, harvestmen, ticks, and mites. In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings Scorpions are eight-legged Carnivorous Arthropods They are members of the order Scorpiones within the class Arachnida. Harvestmen are eight-legged Invertebrate animals belonging to the order Opiliones (formerly Phalangida) in the class Arachnida in the subphylum Tick is the common name for the small Arachnids in Superfamily Ixodoidea that along with other Mites constitute the Acarina. Mites, along with Ticks belong to the subclass Acarina (also known as Acari and the class Arachnida Mites are among the most diverse and successful

It is commonly understood that arachnids have four pairs of legs, and that arachnids may be easily distinguished from insects by this fact (insects have six legs or three pairs). Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Interestingly, arachnids generally have a total of 6 pairs of appendages — two pairs of which have become adapted for feeding, defense, and sensory perception. The first pair of appendages, the chelicerae, serve in feeding and defense. The Chelicerae are mouth parts of the Chelicerata, an Arthropod Subphylum that includes Arachnids, Merostomata The next pair of appendages, the pedipalps have been adapted for feeding, locomotion, and/or reproductive functions. Pedipalps, are the second pair of Appendages of the Prosoma in the subphylum Chelicerata. Reproduction is the Biological process by which new individual Organisms are produced In Solifugae, the palpi are quite leg-like and make Solifugae appear to have ten legs. Solifugae is an order of Arachnida containing more than 1000 described Species in about 140 genera. The larvae of mites (and Ricinulei) have only six legs; the fourth pair appears when they moult into nymphs. A larva ( Latin; plural larvae) is a juvenile form of Animal with indirect development, undergoing Metamorphosis (for example The Order Ricinulei is a group of Arachnids known as hooded tickspiders. Ecdysis is the Molting of the Cuticula in Arthropods and related groups ( Ecdysozoa) In Biology, a nymph is the immature form of some Insects which undergoes incomplete metamorphosis ( Hemimetabolism) before reaching its adult However, there are also adult mites with six, or even four legs. ^[2]

Arachnids are further distinguished by the fact they have no antennae and no wings. Antennae (singular antenna) are paired Appendages connected to the front-most segments of Arthropods In Crustaceans they are Insect wings are outgrowths of the Insect Exoskeleton that enable insects to fly. Their body is organized into two tagma called the prosoma, or cephalothorax, and the opisthosoma, or abdomen. The cephalothorax (call prosoma in some groups is an anatomical term used in Arachnids and Malacostracan Crustaceans for the The cephalothorax (call prosoma in some groups is an anatomical term used in Arachnids and Malacostracan Crustaceans for the The opisthosoma is the posterior portion of the Arachnids body behind the Prosoma (cephalothorax In Vertebrates such as Mammals the abdomen (belly constitutes the part of the body between the Thorax (chest and Pelvis. The cephalothorax (prosoma) is derived from the fusion of the cephalon (head) and the thorax. The cephalothorax (call prosoma in some groups is an anatomical term used in Arachnids and Malacostracan Crustaceans for the Cephalon Inc ( is a US biopharmaceutical company co-founded in 1987 by Dr The thorax is a division of an Animal 's body that lies between the head and the Abdomen. The abdomen (opisthosoma) can be further divided into the preabdomen and postabdomen in many taxa, although in some orders such as the Acari the abdominal sections are fused. In Vertebrates such as Mammals the abdomen (belly constitutes the part of the body between the Thorax (chest and Pelvis. Acarina or Acari are a Taxon of Arachnids that contains Mites and Ticks The diversity of the Acari is extraordinary and its ^[3]

There are some important modifications that are particularly important for the terrestrial lifestyle of an arachnid, such as internal respiratory surfaces in the form of trachea, or modification of the book gill into a book lung, an internal series of vascular lamellae used for gas exchange with the air. Many terrestrial Arthropods have evolved a closed Respiratory system composed of Spiracles, tracheae and Tracheoles to transport metabolic A book lung is a type of Respiration organ used for atmospheric gas exchange and is found in Arachnids such as Scorpions and Spiders Each of these A book lung is a type of Respiration organ used for atmospheric gas exchange and is found in Arachnids such as Scorpions and Spiders Each of these Gas exchange or respiration takes place at a respiratory surface—a boundary between the external environment and the interior of the body Further adaptations are appendages modified for more efficient locomotion on land, internal fertilisation, special sensory organs, and water conservation enhanced by more efficient excretory structures (coxal glands and Malpighian tubules) as well as a waxy layer covering the cuticle. An appendage in the broadest sense is an additional or subsidiary part existing on or added to something which can generally still function if the appendage has never existed or Water is a common Chemical substance that is essential for the survival of all known forms of Life. Excretion is the process of eliminating waste products of Metabolism and other non-useful materials The Malpighian tubule system is a type of Excretory and osmoregulatory system found in some Uniramia ( Insects and Myriapoda)

Arachnids are mostly carnivorous, feeding on the pre-digested bodies of insects and other small animals. A carnivore (ˈkɑrnɪvɔər meaning 'meat eater' ( Latin carne meaning 'flesh' and vorare meaning 'to devour' is any animal with a diet consisting Only in the harvestmen and among mites, such as the house dust mite, is there ingestion of solid food particles and thus exposure to internal parasites ^[4], althougth it is not unusual for spiders to eat their own silk. Harvestmen are eight-legged Invertebrate animals belonging to the order Opiliones (formerly Phalangida) in the class Arachnida in the subphylum Mites, along with Ticks belong to the subclass Acarina (also known as Acari and the class Arachnida Mites are among the most diverse and successful The house dust mite (sometimes abbreviated by Allergists to HDM) is a cosmopolitan guest in Human habitation Several groups are largely venomous — they secrete venom from specialized glands to kill prey or enemies. This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation. A gland is an organ in an animal's body that synthesizes a substance for release such as Hormones or Breast milk, often into the Bloodstream Several mites are parasites, some of which are carriers of disease. Parasitism is a type of symbiotic relationship between Organisms of different Species. A disease is an abnormal condition of an organism that impairs bodily functions and can be deadly Arachnids usually lay eggs, which hatch into immatures that resemble adults, but scorpions bear live young. In most Birds and Reptiles an egg ( Latin ovum) is the Zygote, resulting from Fertilization of the Ovum.

It is true that all arthropods have exoskeletons, and they also have an internal structure of cartilage like tissue called the endosternite, where certain muscle groups are attached. Cartilage is a type of dense Connective tissue. It is composed of specialized cells called chondrocytes that produce a large amount of extracellular matrix Calcification in the endosternite has been found in some Opiliones [1].

Arachnids have two kinds of eyes, the lateral and median ocelli. An ocellus (plural ocelli) is a type of Photoreceptor organ in animals The lateral ocelli evolved from compound eyes and may have a tapetum, which enhances the efficiency of photon capture. The tapetum lucidum ( Latin: "bright tapestry" plural tapeta lucida) is a layer of tissue in the Eye of many Vertebrate animals that In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena The median ocelli develop from a transverse fold of the ectoderm. The ectoderm is the start of a tissue that covers the body surfaces The ancestors of modern arachnids probably had both types, but modern ones often lack one type or the other. ^[4]

Contents 1 Systematics 1.1 Acarina 1.2 Amblypygi 1.3 Araneae 1.4 Haptopoda 1.5 Opiliones 1.6 Palpigradi 1.7 Phalangiotarbida 1.8 Pseudoscorpions 1.9 Ricinulei 1.10 Schizomida 1.11 Scorpions 1.12 Solifugae 1.13 Trigonotarbida 1.14 Uropygi 2 References 3 See also

Systematics

• † Trigonotarbida — extinct
• Amblypygi — "blunt rump" tailless whip scorpions with front legs modified into whip-like sensory structures as long as 25 cm or more (140 species)

†Trilobita Xiphosura Eurypterida Arachnida Scorpiones Opiliones Pseudoscorpiones Solifugae Acari Palpigradi Pycnogonida †Trigonotarbida Ricinulei Araneae Amblypygi Uropygi Schizomida Phylogeny of the Chelicerata (after Giribet et al. The Order Trigonotarbida is an extinct group of Arachnids whose Fossil record extends from the Silurian to the Lower Permian and are Amblypygi is an order of Invertebrate Animals belonging to the class Arachnida in the Subphylum Chelicerata of the The word whip describes two basic types of tools A long stick-like device usually slightly flexible with a small bit of leather or cord called a "popper" on the Trilobites ("three-lobes" are extinct Arthropods that form the class Trilobita. Xiphosura is a class of marine chelicerates which includes a large number of extinct lineages and only four recent species in the family Limulidae, which The eurypterids (sea scorpions include the largest known Arthropod that ever lived (with the possible exception of Arthropleuridae) Scorpions are eight-legged Carnivorous Arthropods They are members of the order Scorpiones within the class Arachnida. Harvestmen are eight-legged Invertebrate animals belonging to the order Opiliones (formerly Phalangida) in the class Arachnida in the subphylum A pseudoscorpion, (also known as a false scorpion or book scorpion) is an Arachnid belonging to the order Pseudoscorpionida, also known Solifugae is an order of Arachnida containing more than 1000 described Species in about 140 genera. Acarina or Acari are a Taxon of Arachnids that contains Mites and Ticks The diversity of the Acari is extraordinary and its A palpigrade, commonly known as a microwhip scorpion, is an invertebrate animal belonging to the order Palpigradi in the class Arachnida, in the subphylum Sea spiders, also called Pantopoda or pycnogonids ('pycnogonid' = Greek for 'thick knee' are marine Arthropods of class Pycnogonida The Order Trigonotarbida is an extinct group of Arachnids whose Fossil record extends from the Silurian to the Lower Permian and are The Order Ricinulei is a group of Arachnids known as hooded tickspiders. Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings Amblypygi is an order of Invertebrate Animals belonging to the class Arachnida in the Subphylum Chelicerata of the A uropygid, commonly known as a whip scorpion, is an invertebrate animal belonging to the former order "Uropygi" in the class Arachnida, Schizomida is an order of Arachnids superficially resembling spiders and generally less than 5mm in length 2002)

• Araneae — spiders (40,000 species)
  • Mesothelae — very rare, basal spiders, with abdomen segmented and spinnerets median
  • Opisthothelae — spiders with abdomen unsegmented and spinnerets located posteriorly
    • Araneomorphae — most common spiders
    • Mygalomorphae — tarantulas and tarantula-like spiders
• † Phalangiotarbida — extinct
• Opiliones — phalangids, harvestmen or daddy-long-legs (6,300 species)
• Palpigradi — microwhip scorpions (80 species)
• Pseudoscorpionida — pseudoscorpions (3,000 species)
• Ricinulei — ricinuleids, hooded tickspiders (60 species)
• Schizomida — "split middle" whip scorpions with divided exoskeletons (220 species)
• Scorpiones — scorpions (2,000 species)
• Solifugae — solpugids, windscorpions, sun spiders or camel spiders (900 species)
• † Haptopoda — extinct
• Uropygi — whip scorpion, forelegs modified into sensory appendages and a long tail on abdomen tip (100 species)
• Acarina — mites and ticks (30,000 species)
  • Acariformes
    • Sarcoptiformes
    • Trombidiformes
  • Opilioacariformes
  • Parasitiformes — holothyrans, ticks and mesostigmatic mites

It is estimated that a total of 98,000 arachnid species have been described, and that there may be up to 600,000 in total, including undescribed species ^[5]. Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings The Mesothelae are a suborder of Spiders (Order Araneae that includes the extinct families Arthrolycosidae and Arthromygalidae and the only Extant In Phylogenetics, a basal Clade is the earliest clade to branch in a larger clade it appears at the base of a cladogram A spinneret is a spider's silk -spinning organ. It is usually on the underside of a spider's Abdomen, to the rear Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings The Araneomorphae are a Suborder of Spiders They are distinguished by having Chelicerae (fangs that point diagonally forward and cross in a pinching action Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings The Mygalomorphae, (also called the Orthognatha) are an Infraorder of Spiders The latter name comes from the orientation of the fangs which Tarantula is the common name for a group of hairy and often very large Spiders belonging to the family Theraphosidae, of which approximately 900 species Phalangiotarbi ( Haase, 1890 is an extinct arachnid order first recorded from the Early Devonian of Germany and most widespread in the Upper Harvestmen are eight-legged Invertebrate animals belonging to the order Opiliones (formerly Phalangida) in the class Arachnida in the subphylum A palpigrade, commonly known as a microwhip scorpion, is an invertebrate animal belonging to the order Palpigradi in the class Arachnida, in the subphylum A pseudoscorpion, (also known as a false scorpion or book scorpion) is an Arachnid belonging to the order Pseudoscorpionida, also known The Order Ricinulei is a group of Arachnids known as hooded tickspiders. Schizomida is an order of Arachnids superficially resembling spiders and generally less than 5mm in length Scorpions are eight-legged Carnivorous Arthropods They are members of the order Scorpiones within the class Arachnida. Solifugae is an order of Arachnida containing more than 1000 described Species in about 140 genera. Haptopoda is an extinct arachnid order known exclusively from a few specimens from the Upper Carboniferous of Coseley Staffordshire UK. A uropygid, commonly known as a whip scorpion, is an invertebrate animal belonging to the former order "Uropygi" in the class Arachnida, Acarina or Acari are a Taxon of Arachnids that contains Mites and Ticks The diversity of the Acari is extraordinary and its Mites, along with Ticks belong to the subclass Acarina (also known as Acari and the class Arachnida Mites are among the most diverse and successful Tick is the common name for the small Arachnids in Superfamily Ixodoidea that along with other Mites constitute the Acarina. The Acariformes are the most diverse of the two superorders of Mites There are over 32000 described species in 351 families and a total estimates of 440000 to 929000 Acarina or Acari are a Taxon of Arachnids that contains Mites and Ticks The diversity of the Acari is extraordinary and its The Parasitiformes are a superorder of Acari (treated as a suborder in an outdated classification

Acarina

Main article: Acarina

Acarina or Acari are a taxon of arachnids that contains mites and ticks. Ixodes ricinus, known as the sheep tick or castor bean tick, is a hard-bodied Tick (family Ixodidae) of Europe. Acarina or Acari are a Taxon of Arachnids that contains Mites and Ticks The diversity of the Acari is extraordinary and its A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to Mites, along with Ticks belong to the subclass Acarina (also known as Acari and the class Arachnida Mites are among the most diverse and successful Tick is the common name for the small Arachnids in Superfamily Ixodoidea that along with other Mites constitute the Acarina. Its fossil history goes back to the Devonian era, although there is also a questionable Ordovician record. The Devonian is a geologic period and system of the Paleozoic era spanning from to  million years ago. The Ordovician is a geologic period and system, the second of six of the Paleozoic era, and covers the time between 488 The Devonian era was the time frame in which certain species of animals developed legs. In most modern treatments, the Acari is considered a subclass of Arachnida and is composed of 2–3 orders or superorders: Acariformes, Parasitiformes, and Opilioacariformes. Arachnids are a class ( Arachnida) of joint-legged Invertebrate Animals in the subphylum Chelicerata. The Acariformes are the most diverse of the two superorders of Mites There are over 32000 described species in 351 families and a total estimates of 440000 to 929000 The Parasitiformes are a superorder of Acari (treated as a suborder in an outdated classification Most acarines are minute to small (e. g. 0. 080–1. 00 mm), but the giants of the Acari (some ticks and red velvet mites) may reach lengths of 10–20 mm. It is estimated that over 50,000 species have been described (as of 1999) and that a million or more species are currently living. Year 1999 ( MCMXCIX) was a Common year starting on Friday (link will display full 1999 Gregorian calendar) The study of mites and ticks is called acarology. Acarina or Acari are a Taxon of Arachnids that contains Mites and Ticks The diversity of the Acari is extraordinary and its ^[6]

Only the faintest traces of primary segmentation remain in mites, the prosoma and opisthosoma being insensibly fused, and a region of flexible cuticle (the cirumcapitular furrow) separates the chelicerae and pedipalps from the rest of the body. This anterior body region is called the capitulum or gnathosoma and is also found in the Ricinulei. The Order Ricinulei is a group of Arachnids known as hooded tickspiders. The remainder of the body is called the idiosoma and is unique to mites. Idiosoma is also the terminus for an anatomical structure of Mites Idiosoma is a genus of trapdoor spiders in the family Most adult mites have four pairs of legs, like other arachnids, but some have fewer. Arachnids are a class ( Arachnida) of joint-legged Invertebrate Animals in the subphylum Chelicerata. For example, gall mites like Phyllocoptes variabilis (superfamily Eriophyioidea) have a wormlike body with only two pairs of legs; some parasitic mites have only one or three pairs of legs in the adult stage. Eriophyidae is a family of more than 200 genera of Mites which live as Plant Parasites commonly causing Galls or other damage to the plant Larval and prelarval stages have a maximum of three pairs of legs; adult mites with only three pairs of legs may be called 'larviform'.

Acarine ontogeny consists of an egg, a prelarval stage (often absent), a larval stage (hexapod except in Eriophyoidea, which have only 2 pairs of legs), and a series of nymphal stages. Ontogeny, as opposed to Phylogeny, refers to the history of an organism from birth as opposed to its genetic makeup Larvae (and prelarvae) have a maximum of 3 pairs of legs (legs are often reduced to stubs or absent in prelarvae); legs IV are added at the first nymphal stage.

Acarines live in practically every habitat, and include aquatic (freshwater and sea water) and terrestrial species. An ecoregion ( ecological region) sometimes called a bioregion, is an ecologically and geographically defined area smaller than a "realm" or " They outnumber other arthropods in the soil organic matter and detritus. Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " Organic matter (or organic material) is Matter that has come from a once-living Organism; is capable of In Biology, detritus is non-living particulate organic material (as opposed to dissolved organic material Many are parasitic, and they affect both vertebrates and invertebrates. Parasitism is a type of symbiotic relationship between Organisms of different Species. Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes An invertebrate is an Animal lacking a Vertebral column. The group includes 98% of all animal Species — all animals except those in the Chordate Most parasitic forms are external parasites, while the free living forms are generally predaceous and may even be used to control undesirable arthropods. Others are detritivores that help to break down forest litter and dead organic matter such as skin cells. Detritivores, also known as detritus feeders or saprophages, are Heterotrophs that obtain Nutrients by consuming Detritus (decomposing Plant litter (sometimes called leaf litter or tree litter) is dead Plant material such as leaves, Bark, and Twigs The skin is the outer covering of living tissue of an animal (or plant Others still are plant feeders and may damage crops. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell Damage to crops is perhaps the most costly economic effect of mites, especially by the spider mites and their relatives (Tetranychoidea), earth mites (Penthaleidae), thread-footed mites (Tarsonemidae) and the gall and rust mites (Eriophyoidea). Penthaleidae, also referred to as earth mites are a family of Mites that are major winter pests of a variety of crops and pastures in southern Australia Tarsonemidae is a family of Mites also called thread-footed mites or white mites. Some parasitic forms affect humans and other mammals, causing damage by their feeding, and can even be vectors of diseases such as scrub typhus and rickettsial pox. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands In Epidemiology, a vector is an Organism that does not cause Disease itself but which transmits Infection by conveying Pathogens from Scrub typhus is a form of Typhus caused by Orientia tsutsugamushi. Rickettsia is a Genus of motile, Gram-negative, non-sporeforming, highly Pleomorphic bacteria that can present A well-known effect of mites on humans is their role as an allergen and the stimulation of asthma in people affected by the repiratory disease. An allergen is a nonparasitic Antigen capable of stimulating a Type-I hypersensitivity reaction in atopic individuals Asthma is a chronic Condition involving the Respiratory system in which the airways occasionally constrict become inflamed, and are The use of predatory mites (e. g. Phytoseiidae) in pest control and herbivorous mites that attack weeds are also of importance. Phytoseiidae is a family of Mites which feed on Thrips and other mite species Pest control refers to the regulation or management of a Species defined as a pest, usually because it is perceived to be detrimental to a person's Health WEED (1390 AM) is a Radio station broadcasting a Spanish format An unquantified, but major positive contribution of the Acari is their normal functioning in ecosystems, especially their roles in the decomposer subsystem ^[6]. An ecosystem is a natural unit consisting of all plants animals and micro-organisms( Biotic factors in an area functioning together with all of the non-living physical (

Amblypygi

Main article: Amblypygi

Amblypygids are also known as tailless whip scorpions or cave spiders. Amblypygi is an order of Invertebrate Animals belonging to the class Arachnida in the Subphylum Chelicerata of the Approximately 5 families, 17 genera and 136 species have been described. They are found in tropical and subtropical regions worldwide. The Tropics are centered on the Equator and limited in Latitude by the Tropic of Cancer in the northern hemisphere at approximately 23°26' (23 The subtropics are the zones of the Earth immediately north and south of the tropic zone which is bounded by the Tropic of Cancer and the Tropic of Some species are subterranean; many are nocturnal. As an Animal behavior, nocturnality describes sleeping during the Daytime and being active at Night - the opposite of the diurnal During the day, they may hide under logs, bark, stones, or leaves. They prefer a humid environment. Amblypygids may range from 5 to 40 mm. The Millimetre ( American spelling: millimeter, symbol mm) is a unit of Length in the Metric system, equal to Their bodies are broad and highly flattened and the first pair of legs (the first walking legs in most arachnid orders) are modified to act as sensory organs. (Compare solifugids, uropygids, and schizomids. Solifugae is an order of Arachnida containing more than 1000 described Species in about 140 genera. A uropygid, commonly known as a whip scorpion, is an invertebrate animal belonging to the former order "Uropygi" in the class Arachnida, Schizomida is an order of Arachnids superficially resembling spiders and generally less than 5mm in length ) These very thin modified legs can extend several times the length of body. They have no silk glands or venomous fangs, but can have prominent pincer-like pedipalps. Silk is a natural Protein Fiber, some forms of which can be woven into Textiles The best-known type of silk is obtained from cocoons This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation. Pedipalps, are the second pair of Appendages of the Prosoma in the subphylum Chelicerata. Amblypygids often move about sideways on their six walking legs, with one "whip" pointed in the direction of travel while the other probes on either side of them. Prey are located with these "whips", captured with pedipalps, then torn to pieces with chelicerae. The Chelicerae are mouth parts of the Chelicerata, an Arthropod Subphylum that includes Arachnids, Merostomata Fossilised amblypygids have been found dating back to the Carboniferous period. FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359

Amblypygids, particularly the species Phrynus marginemaculatus and Damon diadema, are thought to be one of the few species of arachnids that show signs of social behavior. In Biology, Psychology and Sociology social behavior is behavior directed towards society or taking place between members of the same species Research conducted at Cornell University by entomologists suggests that mother amblypygids comfort their young by gently caressing the offspring with her feelers. Further, when two or more siblings were placed in an unfamiliar environment, such as a cage, they would seek each other out and gather back in a group ^[7]

Araneae

Main article: spider

Spiders are the most familiar of the arachnids, and the most numerous, if only described species are counted. The European garden spider ( Araneus diadematus) or diadem spider, also called the cross spider in Eastern Europe, is a very common and well-known Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings All spiders produce silk, a thin, strong protein strand extruded by the spider from spinnerets most commonly found on the end of the abdomen. Spider silk, also known as Gossamer, is a Protein Fiber spun by Spiders Spiders use their silk to make webs or other structures which function Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl A spinneret is a spider's silk -spinning organ. It is usually on the underside of a spider's Abdomen, to the rear Many species use it to trap insects in webs, although there are many species that hunt freely. Silk can be used to aid in climbing, form smooth walls for burrows, build egg sacs, wrap prey, and temporarily hold sperm, even flying, among other applications. Ballooning is a term used for the mechanical kiting that many Spiders as well as certain Mites and some Caterpillars use to disperse through the air never

All spiders except those in the families Uloboridae and Holarchaeidae, and in the suborder Mesothelae (together about 350 species) can inject venom to protect themselves or to kill and liquefy prey. The hackled orbweavers (family Uloboridae) have the special distinction of being non- venomous Spiders Their lack of poison glands is a secondary evolved The Holarchaeidae are a Spider family with only two described species in one genus The Mesothelae are a suborder of Spiders (Order Araneae that includes the extinct families Arthrolycosidae and Arthromygalidae and the only Extant This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation. Only about 200 species, however, have bites that can pose health problems to humans. '''Spiders''' occasionally bite humans Although 98-99% of spider bites are harmless more rarely the symptoms of their bites can include necrotic wounds systemic ^[8] Many larger species' bites may be painful, but will not produce lasting health concerns.

Spiders are found all over the world, from the tropics to the Arctic, with some extreme species even living underwater in silken domes they supply with air, and on the tops of the highest mountains.

Haptopoda

Main article: Haptopoda

Haptopoda is an extinct order known exclusively from a few specimens from the Upper Carboniferous of the United Kingdom. Haptopoda is an extinct arachnid order known exclusively from a few specimens from the Upper Carboniferous of Coseley Staffordshire UK. The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359 The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located It is monotypic, i. e. , has only one species, Plesiosiro madeleyi Pocock 1911. Relationships with other arachnids are obscure, but closest relatives may be the Amblypygi, Thelyphonida and Schizomida of the tetrapulmonate clade ^[9]

Opiliones

Main article: Opiliones

Opiliones (better known as "harvestmen" or ""daddy longlegs"") are arachnids that are harmless to people and are known for their exceptionally long walking legs, compared to their body size. Amblypygi is an order of Invertebrate Animals belonging to the class Arachnida in the Subphylum Chelicerata of the A uropygid, commonly known as a whip scorpion, is an invertebrate animal belonging to the former order "Uropygi" in the class Arachnida, Schizomida is an order of Arachnids superficially resembling spiders and generally less than 5mm in length Paroligolophus agrestis is a species of Harvestman. It occurs in central Europe. Harvestmen are eight-legged Invertebrate animals belonging to the order Opiliones (formerly Phalangida) in the class Arachnida in the subphylum As of 2005, over 6,300 species of Phalangids have been discovered worldwide. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. The order Opiliones can be divided in four suborders: Cyphophthalmi, Eupnoi, Dyspnoi and Laniatores. The Cyphophthalmi are a suborder of Harvestmen, with about 36 genera and more than hundred described species The Eupnoi are a suborder of Harvestmen, with more than 200 genera and about 1700 described species The Dyspnoi are a suborder of Harvestmen, with about 32 genera and about 320 described species Laniatores is the largest suborder of the Arachnid order Opiliones with over 4000 described species worldwide Well-preserved fossils have been found in the 400-million year old Rhynie cherts of Scotland, which look surpringly modern, indicating that the basic structure of the harvestmen hasn't changed much since then. The Rhynie chert is an Early Devonian Lagerstätte found near the village of Rhynie, Aberdeenshire, Scotland, containing exceptionally Their closest relatives are probably the mites (Acari). Acarina or Acari are a Taxon of Arachnids that contains Mites and Ticks The diversity of the Acari is extraordinary and its

The difference between harvestmen and spiders is that in harvestmen the two main body sections (the abdomen with ten segments and cephalothorax, or prosoma and opisthosoma) are nearly joined, so that they appear to be one oval structure. In Vertebrates such as Mammals the abdomen (belly constitutes the part of the body between the Thorax (chest and Pelvis. The cephalothorax (call prosoma in some groups is an anatomical term used in Arachnids and Malacostracan Crustaceans for the The cephalothorax (call prosoma in some groups is an anatomical term used in Arachnids and Malacostracan Crustaceans for the The opisthosoma is the posterior portion of the Arachnids body behind the Prosoma (cephalothorax In geometry an oval or ovoid (from Latin ovum, 'egg' is any Curve resembling an egg or an Ellipse. In more advanced species, the first five abdominal segments are often fused into a dorsal shield called the scutum, which is normally fused with the carapace. Sometimes this shield is only present in males. The two most posterior abdominal segments can be reduced or separated in the middle on the surface to form two plates lying next to each other. The second pair of legs are longer than the others and works as antennae. They have a single pair of eyes in the middle of their heads, orientated sideways. They have a pair of prosomatic scent glands that secrete a peculiar smelling fluid when disturbed. Scent glands are found in the genital area of most Mammals and in various other parts of the body such as the underarms of Humans and the Preorbital Harvestmen do not have silk glands and do not possess poison glands, posing absolutely no danger to humans. They breathe through tracheae. Many terrestrial Arthropods have evolved a closed Respiratory system composed of Spiracles, tracheae and Tracheoles to transport metabolic Between the base of the fourth pair of legs and the abdomen a pair of spiracles are located, one opening on each side. Spiracles are small openings on the surface of some Animals that usually lead to Respiratory systems In Elasmobranchs ( Sharks and In more active species, spiracles are also found upon the tibia of the legs. The tibia, shinbone, or shankbone is the larger and stronger of the two Bones in the Leg below the Knee in vertebrates and connects They have a gonopore on the ventral cephalothorax, and the copulation is direct as the male has a penis (while the female has an ovipositor). A gonopore is a Genital Pore in some Invertebrates and especially some Insects For insects it is the opening of the genital duct The cephalothorax (call prosoma in some groups is an anatomical term used in Arachnids and Malacostracan Crustaceans for the Sexual intercourse, in its biological sense is the act in which the male reproductive organ (in humans and other higher animals enters the female reproductive tract The penis (plural penises, penes The ovipositor is an organ used by some of the Animals for Oviposition, i

Typical body length does not exceed 7 mm (about ¼ in) even in the largest species. The Millimetre ( American spelling: millimeter, symbol mm) is a unit of Length in the Metric system, equal to Inches redirects here To see the Les Savy Fav album see Inches. However, leg span is much larger and can exceed 160 mm (over 6 in). Most species live for a year. Many species are omnivorous, eating primarily small insects and all kinds of plant material and fungi; some are scavengers of the decays of any dead animal, bird dung and other fecal material. Omnivores (from Latin omne all everything vorare to devour are species that eat both Plants and Animals as their primary A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Scavenging, or necrophagy, is a Carnivorous Feeding behaviour in which a predator consumes Corpses or Carrion that were killed Feces, faeces, or fæces (see spelling differences) is a waste product from an animal's digestive tract expelled through the Anus Mating involves direct copulation, rather than the deposition of a spermatophore. In Biology, mating is the pairing of opposite- Sex or hermaphroditic Organisms for copulation and in Social animals also to raise their Sexual intercourse, in its biological sense is the act in which the male reproductive organ (in humans and other higher animals enters the female reproductive tract A spermatophore is a capsule or mass created by males of various Animal species containing Spermatozoa and transferred in entirety to the female's Ovipore They are mostly nocturnal and coloured in hues of brown, although there are a number of diurnal species that have vivid patterns in yellow, green and black with varied reddish and blackish mottling and reticulation. As an Animal behavior, nocturnality describes sleeping during the Daytime and being active at Night - the opposite of the diurnal In Animal behavior, diurnality indicates an Animal that is active during the Daytime and rests during the Night.

Palpigradi

Main article: Palpigradi

Palpigradi, commonly known as "microwhip scorpions", are tiny cousins of the uropygid, or whip scorpion, no more than 3 mm in length. A palpigrade, commonly known as a microwhip scorpion, is an invertebrate animal belonging to the order Palpigradi in the class Arachnida, in the subphylum A uropygid, commonly known as a whip scorpion, is an invertebrate animal belonging to the former order "Uropygi" in the class Arachnida, A uropygid, commonly known as a whip scorpion, is an invertebrate animal belonging to the former order "Uropygi" in the class Arachnida, They have a thin, pale, segmented carapace that terminates in a whip-like flagellum, made up of 15 segments. The carapace is divided into two plates between the third and fourth leg set. They have no eyes. Some species have three pairs of book lungs, while others have no lungs at all. A book lung is a type of Respiration organ used for atmospheric gas exchange and is found in Arachnids such as Scorpions and Spiders Each of these Approximately 80 species of Palpigradi have been described worldwide, all in the family Eukoeneniidae, which contains four genera.

They are believed to be predators like their larger relatives, feeding on minuscule insects in their habitat. Their mating habits are unknown, except that they lay only a few relatively large eggs at a time. Microwhip scorpions need a damp environment to survive, and they always hide from light, so they are commonly found in the moist earth under buried stones and rocks. They can be found on every continent, except in Arctic and Antarctic regions.

Phalangiotarbida

Main article: Phalangiotarbida

Phalangiotarbi (Haase, 1890) is an extinct arachnid order known exclusively from the Palaeozoic (Devonian to Permian) of Europe and North America. Phalangiotarbi ( Haase, 1890 is an extinct arachnid order first recorded from the Early Devonian of Germany and most widespread in the Upper The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life"

The affinities of phalangiotarbids are obscure, with most authors favouring affinities with Opiliones (harvestmen) and/or Acari (mites and ticks). Phalangiotarbida has been recently proposed to be sister group to (Palpigradi+Tetrapulmonata): the taxon Megoperculata sensu Shultz (1990). (Pollitt et al. , 2004).

Pseudoscorpions

Main article: pseudoscorpion

Pseudoscorpions are small arthropods with a flat, pear-shaped body and pincers that resemble those of scorpions. A pseudoscorpion, (also known as a false scorpion or book scorpion) is an Arachnid belonging to the order Pseudoscorpionida, also known Scorpions are eight-legged Carnivorous Arthropods They are members of the order Scorpiones within the class Arachnida. They range from 2 to 8 mm (¹⁄₁₂ to 1/3 inch) in length ^[10]. The Millimetre ( American spelling: millimeter, symbol mm) is a unit of Length in the Metric system, equal to Inches redirects here To see the Les Savy Fav album see Inches. The opisthosoma is made up of twelve segments, each guarded by plate-like tergites above and sternites below. A tergum (plural terga, associated adjective tergal) is the dorsal portion of an Arthropod segment other than the head The sternum (pl "sterna" is the Ventral portion of a segment of an Arthropod Thorax or Abdomen. The abdomen is short and rounded at the rear, rather than extending into a segmented tail and stinger like true scorpions. The colour of the body can be yellowish-tan to dark-brown, with the paired claws often a contrasting colour. They may have two, four or no eyes. They have two very long palpal chelae (pedipalps or pincers) that strongly resemble the pincers found on a scorpion. Pedipalps, are the second pair of Appendages of the Prosoma in the subphylum Chelicerata. The pedipalps generally consist of an immobile "hand" and "finger", with a separate movable finger controlled by an adductor muscle. A venom gland and duct are usually located in the mobile finger; the poison is used to capture and immobilise the pseudoscorpion's prey. This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation. During digestion, pseudoscorpions pour a mildly corrosive fluid over the prey, then ingest the liquefied remains. Pseudoscorpions spin silk from a gland in their jaws to make disk-shaped cocoons for mating, molting, or waiting out cold weather. A pupa ( Latin pupa for doll pl pupae or pupas) is the life stage of some Insects undergoing transformation Another trait they share with their closest relatives, the spiders, is breathing through spiracles. Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings Spiracles are small openings on the surface of some Animals that usually lead to Respiratory systems In Elasmobranchs ( Sharks and Most spiders have one pair of spiracles, and one of book lungs, but pseudoscorpions do not have book lungs. A book lung is a type of Respiration organ used for atmospheric gas exchange and is found in Arachnids such as Scorpions and Spiders Each of these

There are more than 2,000 species of pseudoscorpions recorded. They range worldwide, even in temperate to cold regions, but have their most dense and diverse populations in the tropics and subtropics. The Tropics are centered on the Equator and limited in Latitude by the Tropic of Cancer in the northern hemisphere at approximately 23°26' (23 The subtropics are the zones of the Earth immediately north and south of the tropic zone which is bounded by the Tropic of Cancer and the Tropic of The fossil record of pseudoscorpions dates back over 380 million years, to the Devonian period, near the time when the first land-animal fossils appear. The Devonian is a geologic period and system of the Paleozoic era spanning from to  million years ago.

During the elaborate mating dance, the male of some pseudoscorpion species pulls a female over a spermatophore previously laid upon a surface ^[11]. In Biology, mating is the pairing of opposite- Sex or hermaphroditic Organisms for copulation and in Social animals also to raise their A spermatophore is a capsule or mass created by males of various Animal species containing Spermatozoa and transferred in entirety to the female's Ovipore In other species, the male also pushes the sperm into the female genitals using the forelegs ^[12]. The female carries the fertilised eggs in a brood pouch attached to her abdomen, and the young ride on the mother for a short time after they hatch ^[10]. In Vertebrates such as Mammals the abdomen (belly constitutes the part of the body between the Thorax (chest and Pelvis. Up to two dozen young are hatched in a single brood; there may be more than one brood per year. The young go through three molts over the course of several years before reaching adulthood. Ecdysis is the Molting of the Cuticula in Arthropods and related groups ( Ecdysozoa) Adult pseudoscorpions live 2 to 3 years. They are active in the warm months of the year, overwintering in silken coccoons when the weather grows cold.

Pseudoscorpions are generally beneficial to humans since they prey on clothes moth larvae, carpet beetle larvae, booklice, ants, mites, and small flies. A moth is an Insect closely related to the Butterfly, both being of the order Lepidoptera. Dermestidae are a family of Coleoptera that are commonly referred to as skin beetles Psocoptera are an order of Insects that are commonly known as booklice, barklice or barkflies. Ants are social Insects of the family Formicidae and along with the related families of Wasps and Bees belong to the order Mites, along with Ticks belong to the subclass Acarina (also known as Acari and the class Arachnida Mites are among the most diverse and successful True flies are Insects of the Order Diptera ( Greek: di = two and pteron = wing possessing a single pair of They are small and inoffensive, and are rarely seen due to their size. They usually enter the home by "riding along" with larger insects (known as phoresy), or are brought in with firewood. In Ecology, commensalism is a kind of symbiotic relationship between two organisms where one benefits and the other is not significantly harmed or helped (like a bird They are often observed in bathrooms or laundry rooms, since they seek humidity. They may sometimes be found feeding on mites under the wing covers of certain beetles.

Ricinulei

Main article: Ricinulei

Riniculei (hooded tickspiders) are 5–10 mm long. The Order Ricinulei is a group of Arachnids known as hooded tickspiders. The Millimetre ( American spelling: millimeter, symbol mm) is a unit of Length in the Metric system, equal to Their most notable feature is a "hood" that can be raised and lowered over the head; when lowered, it covers the mouth and the chelicerae. Ricinulei have no eyes. The pedipalps end in pincers that are small relative to their bodies, when compared to those of the related orders of scorpions and pseudoscorpions. Scorpions are eight-legged Carnivorous Arthropods They are members of the order Scorpiones within the class Arachnida. A pseudoscorpion, (also known as a false scorpion or book scorpion) is an Arachnid belonging to the order Pseudoscorpionida, also known The heavy-bodied abdomen forms a narrow pedicel, or waist, where it attaches to the prosoma. The cephalothorax (call prosoma in some groups is an anatomical term used in Arachnids and Malacostracan Crustaceans for the In males, the third pair of legs are modified to form copulatory organs. Malpighian tubules and a pair of coxal glands make up the excretory system. The Malpighian tubule system is a type of Excretory and osmoregulatory system found in some Uniramia ( Insects and Myriapoda) They have no lungs, as gas exchange takes place through the trachea.

Ricinulei are predators, feeding on other small arthropods. Little is known about their mating habits; the males have been observed using their modified third leg to transfer a spermatophore to the female. A spermatophore is a capsule or mass created by males of various Animal species containing Spermatozoa and transferred in entirety to the female's Ovipore The eggs are carried under the mother's hood, until the young hatch into six-legged "larva", which later molt into their adult forms. Ecdysis is the Molting of the Cuticula in Arthropods and related groups ( Ecdysozoa) Ricinulei require moisture to survive. Approximately 57 species of ricinuleids have been described worldwide, all in a single family that contains 3 genera.

Schizomida

Main article: Schizomida

Schizomida is an order of arachnids that tend to live in the top layer of soils. Schizomida is an order of Arachnids superficially resembling spiders and generally less than 5mm in length This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Schizomids present the prosoma covered by a large protopeltidium and smaller, paired, mesopeltidia and metapeltidia. Peltidium is a prodorsal shield found in animals of the Subphylum Chelicerata, in the Phylum Arthropoda. Peltidium is a prodorsal shield found in animals of the Subphylum Chelicerata, in the Phylum Arthropoda. There are no eyes. The opisthosoma is a smooth oval of 12 recognisable somites. The opisthosoma is the posterior portion of the Arachnids body behind the Prosoma (cephalothorax The first is reduced and forms the pedicel. The last three are much constricted, forming the pygidium. The pygidium is the posterior body part or shield of Crustaceans and some Arthropods such as Insects and the extinct Trilobites It contains the The last somite bears the flagellum, which in this order is short and consists of not more than four segments.

The name means "split or cleaved middle", referring to the way the cephalothorax is divided into two separate plates. The cephalothorax (call prosoma in some groups is an anatomical term used in Arachnids and Malacostracan Crustaceans for the Like the related orders Uropygi, Amblypygi, and Solpugida, the schizomids use only six legs for walking, having modified their first two legs to serve as sensory organs. A uropygid, commonly known as a whip scorpion, is an invertebrate animal belonging to the former order "Uropygi" in the class Arachnida, Amblypygi is an order of Invertebrate Animals belonging to the class Arachnida in the Subphylum Chelicerata of the Solifugae is an order of Arachnida containing more than 1000 described Species in about 140 genera. They also have large well-developed pedipalps (pincers) just behind the sensory legs.

Scorpions

Main article: scorpion

Scorpions are characterised by a metasoma (tail) comprising six segments, the last containing the scorpion's anus and bearing the telson (the sting). Scorpio maurus is a species of North African and Middle Eastern Scorpion, also known as the Large-clawed Scorpion or Israeli Scorpions are eight-legged Carnivorous Arthropods They are members of the order Scorpiones within the class Arachnida. The anus is an opening at the opposite end of an Animal 's Digestive tract from the Mouth. The telson is the last division of the body of a Crustacean. It is not considered a true segment because it does not arise in the embryo from teloblast areas A stinger (a Colloquialism for the term "sting" is a common term for a sharp organ or body part found in various Animals (typically Arthropods The telson, in turn, consists of the vesicle, which holds a pair of venom glands and the hypodermic aculeus, the venom-injecting barb. A vesicle is a small bubble of liquid within a cell A more formal definition in Cell biology, would be that a vesicle is a relatively small intracellular membrane-enclosed This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation. The abdomen's front half, the mesosoma, is made up of six segments. The first segment contains the sexual organs as well as a pair of vestigial and modified appendages forming a structure called the genital operculum. A sex organ, or primary sexual characteristic, as narrowly defined is any of the anatomical parts of the body which are involved in sexual reproduction and constitute The second segment bears a pair of featherlike sensory organs known as the pectines; the final four segments each contain a pair of book lungs. A book lung is a type of Respiration organ used for atmospheric gas exchange and is found in Arachnids such as Scorpions and Spiders Each of these The mesosoma is armored with chitinous plates, known as tergites on the upper surface and sternites on the lower surface. Armour (or armor) is protective covering most commonly manufactured from metals to prevent damage from being inflicted to an individual or a vehicle through use of direct contact Chitin ( C 8 H 13 O 5 N)n (ˈkaɪtən is a long-chain Polymer of a N-acetylglucosamine A tergum (plural terga, associated adjective tergal) is the dorsal portion of an Arthropod segment other than the head The sternum (pl "sterna" is the Ventral portion of a segment of an Arthropod Thorax or Abdomen.

The cuticle of scorpions is covered with hairs in some places that act like balance organs. An outer layer that makes them fluorescent green under ultraviolet light is called the hyaline layer. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays Newly molted scorpions do not glow until after their cuticle has hardened. The fluoresent hyaline layer can be intact in fossil rocks that are hundreds of millions of years old.

Scorpions are opportunistic predators of small arthropods and insects. They use their chela (pincers) to catch the prey initially. Depending on the toxicity of their venom and size of their claws, they will then either crush the prey or inject it with neurotoxic venom. Neurotoxicity occurs when the exposure to natural or artificial toxic substances which are called Neurotoxins alters the normal activity of the Nervous system in The neurotoxins consist of a variety of small proteins as well as sodium and potassium cations, which serve to interfere with neurotransmission in the victim. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Scorpions use their venom to kill or paralyze their prey so that it can be eaten; in general it is fast acting, allowing for effective prey capture. Scorpion venoms are optimised for action upon other arthropods and therefore most scorpions are relatively harmless to humans; stings produce only local effects (such as pain, numbness or swelling). Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " A few scorpion species, however, mostly in the family Buthidae, can be dangerous to humans. Buthidae is the largest family of Scorpions containing about 80 Genera and over 800 Species as of mid-2008 The scorpion that is responsible for the most human deaths is the Androctonus australis, or fat-tailed scorpion of North Africa. Fattail scorpion or fat-tailed scorpion is the common name given to Scorpions of the Genus Androctonus, which is one of the most North Africa or Northern Africa is the Northernmost Region of the African Continent, separated by the Sahara from Sub-Saharan The toxicity of A. australis's venom is roughly half that of L. quinquestriatus, but since A. australis injects quite a bit more venom into its prey, it is the most deadly to humans. Human deaths normally occur in the young, elderly, or infirm; scorpions are generally unable to deliver enough venom to kill healthy adults. Some people, however may be allergic to the venom of some species, in which case the scorpion's sting can more likely kill. A primary symptom of a scorpion sting is numbing at the injection site, sometimes lasting for several days. It has been found that scorpions have two types of venom: a translucent, weaker venom designed to stun only, and an opaque, more potent venom designed to kill heavier threats ^[13][14].

Unlike the majority of Arachnida species, scorpions are viviparous. A viviparous Animal is an animal employing vivipary: the embryo develops inside the body of the mother as opposed to outside in an egg ( Ovipary The young are born one by one, and the brood is carried about on its mother's back until the young have undergone at least one moult. Ecdysis is the Molting of the Cuticula in Arthropods and related groups ( Ecdysozoa) ^[15] The young generally resemble their parents, requiring between five and seven moults to reach maturity. Scorpions have quite variable lifespans and the lifespan of most species is not known. The age range appears to be approximately 4–25 years (25 years being the maximum reported life span in the species H. arizonensis). They are nocturnal and fossorial, finding shelter during the day in the relative cool of underground holes or undersides of rocks and coming out at night to hunt and feed. A fossorial is an Organism adapted to digging and life underground such as the Badger, the Naked mole rat, and the mole salamanders Ambystomatidae Scorpions prefer to live in areas where the temperatures range from 20°C to 37 °C (68°F to 99 °F), but may survive in the temperature range of 14 °C to 45 °C (57 °F to 113 °F)^[16][17]. The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724

Scorpions have been found in many fossil records, including coal deposits from the Carboniferous Period and in marine Silurian deposits. The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359 The Silurian is a geologic period and system that extends from the end of the Ordovician period about 443 They are thought to have existed in some form since about 425–450 million years ago. They are believed to have an oceanic origin, with gills and a claw like appendage that enabled them to hold onto rocky shores or seaweed.

Solifugae

Main article: Solifugae

Solifugae is a group of 900 species of arachnids, commonly known as camel spiders, wind scorpions, and sun spiders. Solifugae is an order of Arachnida containing more than 1000 described Species in about 140 genera. The name derives from Latin, and means those that flee from the sun. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Most Solifugae live in tropical or semitropical regions where they inhabit warm and arid habitats, but some species have been known to live in grassland or forest habitats. The most distinctive feature of Solifugae is their large chelicerae. The Chelicerae are mouth parts of the Chelicerata, an Arthropod Subphylum that includes Arachnids, Merostomata Each of the two chelicerae are composed of two articles forming a powerful pincer; each article bears a variable number of teeth. Males in all families but Eremobatidae possess a flagellum on the basal article of the chelicera. Eremobates is a genus of Arachnids of the order Solifugae. About 2 Inches long this fast-moving creature has the largest jaw size A flagellum ( plural flagella) is a tail-like structure that projects from the Cell body of certain Prokaryotic and Eukaryotic cells and it Solifugae also have long pedipalps, which function as sense organs similar to insects' antennae and give the appearance of the two extra legs. Pedipalps, are the second pair of Appendages of the Prosoma in the subphylum Chelicerata. Antennae (singular antenna) are paired Appendages connected to the front-most segments of Arthropods In Crustaceans they are Pedipalps terminate in eversible adhesive organs.

Solifugae are carnivorous or omnivorous, with most species feeding on termites, darkling beetles, and other small arthropods; however, solifugae have been videotaped consuming larger prey such as lizards. A carnivore (ˈkɑrnɪvɔər meaning 'meat eater' ( Latin carne meaning 'flesh' and vorare meaning 'to devour' is any animal with a diet consisting Omnivores (from Latin omne all everything vorare to devour are species that eat both Plants and Animals as their primary The termites are a group of Social Insects usually classified at the taxonomic rank of order Isoptera (but see also taxonomy Darkling beetles (also known as Darkening beetles) are a family of Beetles found worldwide estimated at more than 20000 species. Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " Prey is located with the pedipalps and killed and cut into pieces by the chelicerae. The prey is then liquefied and the liquid ingested through the pharynx. Reproduction can involve direct or indirect sperm transfer; when indirect, the male emits a spermatophore on the ground and then inserts it with his chelicerae in the female's genital pore. The term sperm is derived from the Greek word (σπέρμα sperma (meaning "seed" and refers to the male reproductive cells. A spermatophore is a capsule or mass created by males of various Animal species containing Spermatozoa and transferred in entirety to the female's Ovipore

Trigonotarbida

Main article: Trigonotarbida

The Order Trigonotarbida is an extinct group of arachnids whose fossil record extends from the Silurian to the Lower Permian and are known from several localities in Europe and North America. The Order Trigonotarbida is an extinct group of Arachnids whose Fossil record extends from the Silurian to the Lower Permian and are This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. The Silurian is a geologic period and system that extends from the end of the Ordovician period about 443 The Permian is a geologic period and system that extends from 299 They superficially resemble spiders, to which they were clearly related. Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings It was once thought that trigonotarbids lacked the silk-producing spinnerets that have apparently been crucial to the spider's evolutionary success, though in recent years at least one fossil find seems to show distinct microtubercles on its hind legs, akin to those used by spiders to direct and manipulate their silk. Spider silk, also known as Gossamer, is a Protein Fiber spun by Spiders Spiders use their silk to make webs or other structures which function A spinneret is a spider's silk -spinning organ. It is usually on the underside of a spider's Abdomen, to the rear eVolution is the third Album by eLDee, it was due to be released in 2008

These early arachnids seem to have been adapted to stalking prey on the ground. They have been found within the very structure of ground-dwellings plants, possibly where they hid to await their prey. Trigonotarbids are currently the oldest known land arthropods. They lack silk glands on the opisthosoma and cheliceral poison glands, and most likely represented independent offshoots of the Arachnida. The opisthosoma is the posterior portion of the Arachnids body behind the Prosoma (cephalothorax

Uropygi

Main article: Uropygi

The Uropygi, commonly known as whip scorpions, range from 25 to 85 mm in length; the largest species, of the genus Mastigoproctus, reaches 85 mm. A uropygid, commonly known as a whip scorpion, is an invertebrate animal belonging to the former order "Uropygi" in the class Arachnida, The King Whip is arguably the largest Whip scorpion in the world Like the related orders Schizomida, Amblypygi, and Solifugae, the uropygids use only six legs for walking, having modified their first two legs to serve as antennae-like sensory organs. Schizomida is an order of Arachnids superficially resembling spiders and generally less than 5mm in length Amblypygi is an order of Invertebrate Animals belonging to the class Arachnida in the Subphylum Chelicerata of the Solifugae is an order of Arachnida containing more than 1000 described Species in about 140 genera. Many species also have very large scorpion-like pedipalps (pincers). Scorpions are eight-legged Carnivorous Arthropods They are members of the order Scorpiones within the class Arachnida. They have one pair of eyes at the front of the cephalothorax and three on each side of the head. The cephalothorax (call prosoma in some groups is an anatomical term used in Arachnids and Malacostracan Crustaceans for the Whip scorpions have no poison glands, but they do have glands near the rear of their abdomen that can spray a combination of acetic acid and octanoic acid when they are bothered. Acetic acid, also known as ethanoic acid, is an organic chemical compound, giving Vinegar its sour taste Caprylic acid is the common name for the eight-carbon saturated Fatty acid known by the systematic name octanoic acid. Other species spray formic acid or chlorine. Formic acid (systematically called methanoic acid) is the simplest Carboxylic acid. Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and As of 2006, over 100 species of uropygids have been described worldwide. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar.

Whip scorpions are carnivorous, nocturnal hunters feeding mostly on insects but sometimes on worms and slugs. A carnivore (ˈkɑrnɪvɔər meaning 'meat eater' ( Latin carne meaning 'flesh' and vorare meaning 'to devour' is any animal with a diet consisting The prey is crushed between special teeth on the inside of the trochanters (the second segment of the leg) of the front legs. They are valuable in controlling the population of roaches and crickets.

Males secrete a sperm sac, which is transferred to the female. Up to 35 eggs are laid in a burrow, within a mucous membrane that preserves moisture. The mucous membranes (or mucosae; singular mucosa) are linings of mostly endodermal origin covered in Epithelium, which are involved in Mothers stay with the eggs and do not eat. The white young that hatch from the eggs climb onto their mother's back and attach themselves there with special suckers. After the first molt they look like miniature whip scorpions, and leave the burrow; the mother dies soon after. The young grow slowly, going through three molts in about three years before reaching adulthood.

Uropygids are found in tropical and subtropical areas worldwide, usually in underground burrows that they dig with their pedipalps. The subtropics are the zones of the Earth immediately north and south of the tropic zone which is bounded by the Tropic of Cancer and the Tropic of They may also burrow under logs, rotting wood, rocks, and other natural debris. They enjoy humid, dark places and avoid the light.

References

spiders are cousins to rats.

See also

• Endangered spiders

An endangered species is “a species at risk of extinction because of human activity changes in climate changes in predator-prey ratios etc

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