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Exopod
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip (anatomy), hip, : ''coxae''), ''trochanter'', ''femur'' (: ''femora''), ''tibia'' (: ''tibiae''), ''tarsus'' (: ''tarsi''), ''ischium'' (: ''ischia''), ''metatarsus'', ''carpus'', ''dactylus'' (meaning finger), ''patella'' (: ''patellae''). Homology (biology), Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of Neontology, extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a Homeobox, ''Hox''-gene, could result in Parallel evolution, parallel gains of leg segments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metamerism (biology), metameric) Segmentation (biology), segments, and paired jointed appendages. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. They form an extremely diverse group of up to ten million species. Haemolymph is the analogue of blood for most arthropods. An arthropod has an open circulatory system, with a body cavity called a haemocoel through which haemolymph circulates to the interior Organ (anatomy), organs. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. They have ladder-like nervous systems, with paired Anatomical terms of location#Dorsal and ventral, ventral Ventral nerve cord, nerve cord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isopod
Isopoda is an Order (biology), order of crustaceans. Members of this group are called isopods and include both Aquatic animal, aquatic species and Terrestrial animal, terrestrial species such as woodlice. All have rigid, segmented exoskeletons, two pairs of Antenna (biology), antennae, seven pairs of jointed limbs on the Thorax#In_arthropods, thorax, and five pairs of branching appendages on the Abdomen#In other animals, abdomen that are used in Respiration (physiology), respiration. Females brood their young in a pouch under their thorax called the Brood pouch (Peracarida), marsupium. Isopods have various feeding methods: some eat dead or decaying plant and animal matter, others are Grazing (behaviour), grazers or filter feeders, a few are Predation, predators, and some are internal or external parasites, mostly of fish. Aquatic species mostly live on the seabed or the bottom of freshwater body of water, bodies of water, but some Taxon, taxa can swim for short distance. Terre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metamerism (biology), metameric) Segmentation (biology), segments, and paired jointed appendages. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. They form an extremely diverse group of up to ten million species. Haemolymph is the analogue of blood for most arthropods. An arthropod has an open circulatory system, with a body cavity called a haemocoel through which haemolymph circulates to the interior Organ (anatomy), organs. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. They have ladder-like nervous systems, with paired Anatomical terms of location#Dorsal and ventral, ventral Ventral nerve cord, nerve cord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insect
Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, Thorax (insect anatomy), thorax and abdomen (insect anatomy), abdomen), three pairs of jointed Arthropod leg, legs, compound eyes, and a pair of antenna (biology), antennae. Insects are the most diverse group of animals, with more than a million described species; they represent more than half of all animal species. The insect nervous system consists of a insect brain, brain and a ventral nerve cord. Most insects reproduce Oviparous, by laying eggs. Insects Respiratory system of insects, breathe air through a system of Spiracle (arthropods), paired openings along their sides, connected to Trachea#Invertebrates, small tubes that take air directly to the tissues. The blood therefore does not carry oxygen; it is only partly contained in ves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myriapoda
Myriapods () are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial. Although molecular evidence and similar fossils suggests a diversification in the Cambrian Period, the oldest known fossil record of myriapods dates between the Late Silurian and Early Devonian, with '' Pneumodesmus'' preserving the earliest known evidence of air-breathing on land. Other early myriapod fossil species around the similar time period include '' Kampecaris obanensis'' and '' Archidesmus'' sp. The phylogenetic classification of myriapods is still debated. The scientific study of myriapods is myriapodology, and those who study myriapods are myriapodologists. Anatomy Myriapods have a single pair of antennae and, in most cases, simple eyes. Exceptions are the two classes of symphylans and pauropods, the millipede order Polydesmida and the centipede order Geophilomorpha, which are all ey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladistics
Cladistics ( ; from Ancient Greek 'branch') is an approach to Taxonomy (biology), biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived (phylogenetics), derived characteristics (synapomorphies) that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose Phenotypic trait, character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if the terms ''worms'' or ''fishes'' were used within a ''strict'' cladistic framework, these terms would include humans. Many of these terms are normally used Paraphyly, paraphyletically, outside of cladistics, e.g. as a 'E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uniramia
Uniramia (''uni'' – one, ''ramus'' – branch, i.e. single-branches) is a group within the arthropods. In the past this group included the Onychophora, which are now considered a separate category. The group is currently used in a narrower sense. Uniramia is one of three subphyla in the Arthropoda classification suggested by Sidnie Manton. This classification divided arthropods into a three-phyla polyphyletic group, with phylum Uniramia including the Hexapoda (insects), Myriapoda (centipedes and millipedes) and the Onychophora (velvetworms). The discovery of fossil lobopods, determined to be intermediate between onychophorans and arthropods led to the splintering of the Lobopoda and Onychophora into separate groups. This redefined the Uniramia as strictly "true" arthropods with exoskeletons and jointed appendages. Uniramians have strictly uniramous appendages. Systematics can result in rival taxonomies, and this seems to have happened to Uniramia. The name Uniramia was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spider External Anatomy Appendages En
Spiders (order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except Antarctica, and have become established in nearly every land habitat. , 53,034 spider species in 136 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900. Anatomically, spiders (as with all arachnids) differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax or prosoma, and the opisthosoma, or abdomen, and joined by a small, cylindrical pedicel. However, as there is currently neither paleontological nor embryological evidence that spiders ever had a separate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appendage
An appendage (or outgrowth) is an external body part or natural prolongation that protrudes from an organism's body such as an arm or a leg. Protrusions from single-celled bacteria and archaea are known as cell-surface appendages or surface appendages. In many kinds of eukaryotic cells, the protrusions are known as membrane protrusions or cell appendages (examples include microvilli and cilia). Types in animals In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including antennae, mouthparts (including mandibles, maxillae and maxillipeds), gills, locomotor legs ( pereiopods for walking, and pleopods for swimming), sexual organs ( gonopods), and parts of the tail (uropods). Typically, each body segment carries one pair of appendages. An appendage which is modified to assist in feeding is known as a maxilliped or gnathopod. In annelids lateral protrusions from the body are called parapodia. In echinoderms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arachnid
Arachnids are arthropods in the Class (biology), class Arachnida () of the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, opiliones, harvestmen, Solifugae, camel spiders, Amblypygi, whip spiders and Uropygi, vinegaroons. Adult arachnids have eight Arthropod leg, legs attached to the cephalothorax. In some species the frontmost pair of legs has converted to a sensory function, while in others, different appendages can grow large enough to take on the appearance of extra pairs of legs. Almost all Extant taxon, extant arachnids are terrestrial animal, terrestrial, living mainly on land. However, some inhabit freshwater environments and, with the exception of the pelagic zone, marine environments as well. They comprise over 110,000 named species, of which 51,000 are species of spiders. The term is derived from the Ancient Greek, Greek word (''aráchnē'', 'spider'), from the myth of the hubristic human weaver Arachne, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scorpion
Scorpions are predatory arachnids of the Order (biology), order Scorpiones. They have eight legs and are easily recognized by a pair of Chela (organ), grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always ending with a stinger. The evolutionary history of scorpions goes back Silurian, 435 million years. They mainly live in deserts but have adapted to a wide range of environmental conditions, and can be found on all continents except Antarctica. There are over 2,500 described species, with 22 extant (living) families recognized to date. Their Taxonomy (biology), taxonomy is being revised to account for 21st-century genomic studies. Scorpions primarily prey on insects and other invertebrates, but some species hunt vertebrates. They use their pincers to restrain and kill prey, or to prevent their own predation. The Scorpion sting, venomous sting is used for offense and defense. During courtship, the male and female ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedipalp
Pedipalps (commonly shortened to palps or palpi) are the secondary pair of forward appendages among Chelicerata, chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and anterior to the first pair of walking legs. Overview Pedipalps are composed of six segments or articles. From the proximal end (where they are attached to the body) to the distal, they are: the coxa, the Arthropod leg#Trochanter, trochanter, the Arthropod leg#Femur, femur, the short Glossary_of_spider_terms#patella, patella, the Glossary_of_spider_terms#tibia, tibia, and the Arthropod_leg#Tarsus, tarsus. In spiders, the coxae frequently have extensions called Glossary_of_spider_terms#maxilla , maxillae or gnathobases, which function as mouth parts with or without some contribution from the coxae of the anterior arthropod leg, legs. The limbs themselves may be simple tactile organs outwardly resembling the legs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
