What collective name is given to creatures with segmented bodies, such as insects, arachnids and crustaceans?
"the appearance of marine gastropods, cephalopods and bivalves in the Cambrian period . However, the evolutionary history both of molluscs' emergence from the ancestral Lophotrochozoa and of their diversification into the well-known living and fossil forms are still subjects of vigorous debate among scientists. Arthropods (Greek for ""jointed feet"") have an exoskeleton (external skeleton), a segmented body, and jointed appendages (paired appendages). They form a phylum which includes insects, arachnids, myriapods, and crustaceans. Arthropods are characterized by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a"
"Insect Insects or Insecta (from Latin ') are hexapod invertebrates and the largest group within the arthropod phylum. Definitions and circumscriptions vary; usually, insects comprise a class within the Arthropoda. As used here, the term Insecta is synonymous with Ectognatha. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms. The total number of extant species is estimated at between"
"interpreted this as growth stimulated by food coming down from the leaves, and being captured above the ring. Arthropods comprise the largest phylum in the animal kingdom with over a million known invertebrate species. Insects possess segmented bodies supported by a hard-jointed outer covering, the exoskeleton, made mostly of chitin. The segments of the body are organized into three distinct parts, a head, a thorax and an abdomen. The head typically bears a pair of sensory antennae, a pair of compound eyes, one to three simple eyes (ocelli) and three sets of modified appendages that form the mouthparts. The thorax"
"Segmentation (biology) Segmentation in biology is the division of some animal and plant body plans into a series of repetitive segments. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, and Annelida. These three groups form segments by using a ""growth zone"" to direct and define the segments. While all three have a generally segmented body plan and use a growth zone, they use different mechanisms for generating this patterning. Even within these groups, different organisms have different mechanisms for segmenting the body. Segmentation of the body plan is important"
"for allowing free movement and development of certain body parts. It also allows for regeneration in specific individuals. Segmentation is a difficult process to satisfactorily define. Many taxa (for instance the molluscs) have some form of serial repetition in their units, but are not conventionally thought of as segmented. Segmented animals are those considered to have organs that were repeated, or to have a body composed of self-similar units, but usually it is the parts of an organism that are referred to as being segmented. Segmentation in animals typically falls into three types, characteristic of different arthropods, vertebrates, and annelids."
"internal (as some molluscs) or external (as onychophora), can be seen as 'precursors' to eusegmented organisms such as annelids or arthropods. Segmentation (biology) Segmentation in biology is the division of some animal and plant body plans into a series of repetitive segments. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, and Annelida. These three groups form segments by using a ""growth zone"" to direct and define the segments. While all three have a generally segmented body plan and use a growth zone, they use different mechanisms for generating this"
"specialization of segments is in the head. The four major groups of arthropods – Chelicerata (includes spiders and scorpions), Crustacea (shrimps, lobsters, crabs, etc.), Tracheata (arthropods that breathe via channels into their bodies; includes insects and myriapods), and the extinct trilobites – have heads formed of various combinations of segments, with appendages that are missing or specialized in different ways. In addition, some extinct arthropods, such as ""Marrella"", belong to none of these groups, as their heads are formed by their own particular combinations of segments and specialized appendages. Working out the evolutionary stages by which all these different combinations"
"Arthropodology Arthropodology (from Greek - ""arthron"", ""joint"", and , ""gen"".: - ""pous"", ""podos"", ""foot"", which together mean ""jointed feet"") is a biological discipline concerned with the study of arthropods, a phylum of animals that include the insects, arachnids, crustaceans and others that are characterized by the possession of jointed limbs. This field is very important in medicine, studied together with parasitology. Medical arthropodology is the study of the parasitic effect of arthropods, not only as parasites but also as vectors. The first annual "" Conference on Medical Arthropodology"" was held in Madurai (Tamil Nadu) in 2007. Subfields of arthropodology are"
"Arthropodology Arthropodology (from Greek - ""arthron"", ""joint"", and , ""gen"".: - ""pous"", ""podos"", ""foot"", which together mean ""jointed feet"") is a biological discipline concerned with the study of arthropods, a phylum of animals that include the insects, arachnids, crustaceans and others that are characterized by the possession of jointed limbs. This field is very important in medicine, studied together with parasitology. Medical arthropodology is the study of the parasitic effect of arthropods, not only as parasites but also as vectors. The first annual "" Conference on Medical Arthropodology"" was held in Madurai (Tamil Nadu) in 2007. Subfields of arthropodology are"
"Pygidium The pygidium (plural pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. It contains the anus and, in females, the ovipositor. It is composed of fused body segments, sometimes with a tail, and separated from thoracic segments by an articulation. In arachnids, the pygidium is formed by reduction of the last three opisthosomal segments to rings where there is no distinction between tergites and sternites. A pygidium is present in Palpigradi, Amblypygi, Thelyphonida, Schizomida, Ricinulei and in the extinct order Trigonotarbida. It is also present in early"
"of spiders is called arachnophobia. Spiders are chelicerates and therefore arthropods. As arthropods they have: segmented bodies with jointed limbs, all covered in a cuticle made of chitin and proteins; heads that are composed of several segments that fuse during the development of the embryo. Being chelicerates, their bodies consist of two tagmata, sets of segments that serve similar functions: the foremost one, called the cephalothorax or prosoma, is a complete fusion of the segments that in an insect would form two separate tagmata, the head and thorax; the rear tagma is called the abdomen or opisthosoma. In spiders, the"
"head), the thorax (literally meaning chest, but in this application referring to the mid-portion of the body), and the pygidium (meaning rump). The Hexapoda, including insects, also have three tagmata, usually termed the head, thorax, and abdomen. The bodies of many arachnids, such as spiders, have two tagmata, as do the bodies of some crustaceans: in both groups the anterior tagma may be called the cephalothorax (meaning head plus chest) or the prosoma or prosome (meaning ""fore-part of body""). The posterior tagma may be called the abdomen. In those arachnids that have two tagmata, the abdomen is also called the"
"Tagma (biology) In biology a tagma (Greek: τάγμα, plural tagmata – τάγματα) is a specialized grouping of multiple segments or metameres into a coherently functional morphological unit. Familiar examples are the head, the thorax, and the abdomen of insects. The segments within a tagma may be either fused (such as in the head of an insect) or so jointed as to be independently moveable (such as in the abdomen of most insects). Usually the term is taken to refer to tagmata in the morphology of members of the phylum Arthropoda, but it applies equally validly in other phyla, such as"
"crustaceans, arachnids and others) as: ""A very numerous and various class consisting of small animals, breathing through lateral spiracles, armed on all sides with a bony skin, or covered with hair; furnished with many feet, and moveable antennae (or horns), which project from the head, and are the probable instruments of sensation."" Linnaeus divided the insects based upon the form of the wings, into the following orders and genera: Linnaeus described his ""Vermes"" as: ""Animals of slow motion, soft substance, able to increase their bulk and restore parts which have been destroyed, extremely tenacious of life, and the inhabitants of"
"Crustacean Crustaceans (Crustacea ) form a large, diverse arthropod taxon which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill, woodlice, and barnacles. The crustacean group is usually treated as a subphylum, and because of recent molecular studies it is now well accepted that the crustacean group is paraphyletic, and comprises all animals in the Pancrustacea clade other than hexapods. Some crustaceans are more closely related to insects and other hexapods than they are to certain other crustaceans. The 67,000 described species range in size from ""Stygotantulus stocki"" at , to the Japanese spider crab with a leg span"
"Decapod anatomy The decapod crustacean, such as a crab, lobster, shrimp or prawn, is made up of 20 body segments grouped into two main body parts, the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various groups these may be reduced or missing. They are, from head to tail: The head also bears the (usually stalked) compound eyes. The distal portion of a mandible or maxilla which has a sensory function is known as a palp. Maxillipeds are appendages modified to function as mouthparts. Particularly in the less advanced decapods, these can be"
"shared, derived character, so uniramous arthropods were grouped into a taxon called Uniramia. It is now believed that several groups of arthropods evolved uniramous limbs independently from ancestors with biramous limbs, so this taxon is no longer used. Arachnid legs differ from those of insects by the addition of two segments on either side of the tibia, the patella between the femur and the tibia, and the metatarsus (sometimes called basitarsus) between the tibia and the tarsus (sometimes called telotarsus), making a total of seven segments. The situation is identical in scorpions, but with the addition of a pre-tarsus beyond"
"Malacostraca Malacostraca is the largest of the six classes of crustaceans, containing about 40,000 living species, divided among 16 orders. Its members, the malacostracans, display a great diversity of body forms and include crabs, lobsters, crayfish, shrimp, krill, woodlice, amphipods, mantis shrimp and many other, less familiar animals. They are abundant in all marine environments and have colonised freshwater and terrestrial habitats. They are segmented animals, united by a common body plan comprising 20 body segments (rarely 21), and divided into a head, thorax, and abdomen. The name Malacostraca was coined by a French zoologist Pierre André Latreille in 1802."
"grubs served as personal clan totems. In the case of the 'San' bush-men of the Kalahari, it is the praying mantis that holds much cultural significance including creation and zen-like patience in waiting. Insect Insects or Insecta (from Latin ') are hexapod invertebrates and the largest group within the arthropod phylum. Definitions and circumscriptions vary; usually, insects comprise a class within the Arthropoda. As used here, the term Insecta is synonymous with Ectognatha. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Insects are the"
"while the internal branch is known as the endopod or endopodite. Other structures aside from the latter two are termed exites (outer structures) and endites (inner structures). Exopodites can be easily distinguished from exites by the possession of internal musculature. The exopodites can sometimes be missing in some crustacean groups (amphipods and isopods), and they are completely absent in insects. The legs of insects and myriapods are uniramous. In crustaceans, the first antennae are uniramous, but the second antennae are biramous, as are the legs in most species. For a time, possession of uniramous limbs was believed to be a"
"that live in the spaces between grains of marine sediment, were treated as a separate class because of their simple body structure, but are now regarded as polychaetes. Some other groups of animals have been classified in various ways, but are now widely regarded as annelids: No single feature distinguishes Annelids from other invertebrate phyla, but they have a distinctive combination of features. Their bodies are long, with segments that are divided externally by shallow ring-like constrictions called annuli and internally by septa (""partitions"") at the same points, although in some species the septa are incomplete and in a few"
"Mesosoma The mesosoma is the middle part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the metasoma. It bears the legs, and, in the case of winged insects, the wings. In hymenopterans of the suborder Apocrita (wasps, bees and ants), it consists of the three thoracic segments and the first abdominal segment (the propodeum). For historical reasons, in ants it is commonly referred to by the alternative name alitrunk. In scorpions, it is composed of six segments and forms the first part of the abdomen, containing all"
"as earthworms. Around 453 MYA, animals began diversifying, and many of the important groups of invertebrates diverged from one another. Fossils of invertebrates are found in various types of sediment from the Phanerozoic. Fossils of invertebrates are commonly used in stratigraphy. Carl Linnaeus divided these animals into only two groups, the Insecta and the now-obsolete Vermes (worms). Jean-Baptiste Lamarck, who was appointed to the position of ""Curator of Insecta and Vermes"" at the Muséum National d'Histoire Naturelle in 1793, both coined the term ""invertebrate"" to describe such animals, and divided the original two groups into ten, by splitting Arachnida and"
"invalid, are giving way to prosoma and opisthosoma. The latter two terms carry less of a suggestion of homology with the significantly different tagmata of insects. The development of distinct tagmata is believed to be a feature of the evolution of segmented animals, especially arthropods. In the ancestral arthropod, the body was made up of repeated segments, each with similar internal organs and appendages. One evolutionary trend is the grouping together of some segments into larger units, the tagmata. The evolutionary process of grouping is called tagmosis (or tagmatization). The first and simplest stage was a division into two tagmata:"
"ago. Hexapoda The subphylum Hexapoda (from the Greek for ""six legs"") constitutes the largest number of species of arthropods and includes the insects as well as three much smaller groups of wingless arthropods: Collembola, Protura, and Diplura (all of these were once considered insects). The Collembola (or springtails) are very abundant in terrestrial environments. ""Hexapods"" are named for their most distinctive feature: a consolidated thorax with three pairs of legs (six legs). Most other arthropods have more than three pairs of legs. Hexapods have bodies ranging in length from 0.5 mm to over 300 mm which are divided into an"
"opisthosoma. In crustaceans, the posterior tagma is also called the pleon or the urosome (meaning the tail part); alternatively, ""pleon"" may refer only to the abdominal segments incorporated into the posterior tagma, the thoracic segments in this tagma being called the ""pereon"". Tagma (biology) In biology a tagma (Greek: τάγμα, plural tagmata – τάγματα) is a specialized grouping of multiple segments or metameres into a coherently functional morphological unit. Familiar examples are the head, the thorax, and the abdomen of insects. The segments within a tagma may be either fused (such as in the head of an insect) or so"
"Hexapoda The subphylum Hexapoda (from the Greek for ""six legs"") constitutes the largest number of species of arthropods and includes the insects as well as three much smaller groups of wingless arthropods: Collembola, Protura, and Diplura (all of these were once considered insects). The Collembola (or springtails) are very abundant in terrestrial environments. ""Hexapods"" are named for their most distinctive feature: a consolidated thorax with three pairs of legs (six legs). Most other arthropods have more than three pairs of legs. Hexapods have bodies ranging in length from 0.5 mm to over 300 mm which are divided into an anterior"
"the presence or absence of spines) are heteronomous. ""Pygidium"" is also a superseded genus of fish of the family Trichomycteridae. Most species of this genus have been reassigned to the genus ""Trichomycterus"". Pygidium The pygidium (plural pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. It contains the anus and, in females, the ovipositor. It is composed of fused body segments, sometimes with a tail, and separated from thoracic segments by an articulation. In arachnids, the pygidium is formed by reduction of the last three opisthosomal segments to"
"were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, the Chordata, while his Insecta (which included the crustaceans and arachnids) and Vermes have been renamed or broken up. The process was begun in 1793 by Lamarck, who called the Vermes ""une espèce de chaos"" (a sort of chaos) and split the group into three new phyla, worms, echinoderms, and polyps (which contained corals and jellyfish). By 1809, in his ""Philosophie Zoologique"", Lamarck had created 9 phyla apart from vertebrates"
"cord, and the visceral tracheae supply the guts, fat bodies, and gonads. Insect morphology Insect morphology is the study and description of the physical form of insects. The terminology used to describe insects is similar to that used for other arthropods due to their shared evolutionary history. Three physical features separate insects from other arthropods: they have a body divided into three regions (head, thorax, and abdomen), have three pairs of legs, and mouthparts located ""outside"" of the head capsule. It is this position of the mouthparts which divides them from their closest relatives, the non-insect hexapods, which includes Protura,"
"""Triops cancriformis"", which has existed apparently unchanged since the Triassic period. More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, the majority of it being shrimp and prawns. Krill and copepods are not as widely fished, but may be the animals with the greatest biomass on the planet, and form a vital part of the food chain. The scientific study of crustaceans is known as carcinology (alternatively, ""malacostracology"", ""crustaceology"" or ""crustalogy""), and a scientist who works in carcinology is a carcinologist. The body of a crustacean is composed of segments, which are grouped"
"the animal kingdom containing the brachiopods, bryozoans, and tunicates, the members of the three groups having been supposed to somewhat resemble the molluscs. As it is now known these groups have no relation to molluscs, and very little to one another, the name Molluscoida has been abandoned. The most universal features of the body structure of molluscs are a mantle with a significant cavity used for breathing and excretion, and the organization of the nervous system. Many have a calcareous shell. Molluscs have developed such a varied range of body structures, it is difficult to find synapomorphies (defining characteristics) to"
"into three regions: the ""cephalon"" or head, the ""pereon"" or thorax, and the ""pleon"" or abdomen. The head and thorax may be fused together to form a cephalothorax, which may be covered by a single large carapace. The crustacean body is protected by the hard exoskeleton, which must be moulted for the animal to grow. The shell around each somite can be divided into a dorsal tergum, ventral sternum and a lateral pleuron. Various parts of the exoskeleton may be fused together. Each somite, or body segment can bear a pair of appendages: on the segments of the head, these"