Ectognatha
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Ectognatha
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 ...
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Hexapoda
The subphylum Hexapoda (from Greek for 'six legs') or hexapods comprises the largest clade of arthropods and includes most of the extant arthropod species. It includes the crown group class Insecta (true insects), as well as the much smaller clade Entognatha, which includes three classes of wingless arthropods that were once considered insects: Collembola (springtails), Protura (coneheads) and Diplura (two-pronged bristletails). The insects and springtails are very abundant and are some of the most important pollinators, basal consumers, scavengers/ detritivores and micropredators in terrestrial environments. Hexapods are named for their most distinctive feature: a three-part body plan with a consolidated thorax and three pairs of legs. Most other arthropods have more than three pairs of legs. Most recent studies have recovered Hexapoda as a subgroup of Pancrustacea. Morphology Hexapods have bodies ranging in length from 0.5 mm to over 300 mm which are divided ...
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Compound Eye
A compound eye is a Eye, visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidium, ommatidia, which are tiny independent photoreception units that consist of a cornea, lens (anatomy), lens, and photoreceptor cells which distinguish brightness and color. The image perceived by this arthropod eye is a combination of inputs from the numerous ommatidia, which are oriented to point in slightly different directions. Compared with single-aperture eyes, compound eyes have poor image resolution; however, they possess a very large view angle and the ability to detect fast movement and, in some cases, the Polarization (waves), polarization of light. Because a compound eye is made up of a collection of ommatidia, each with its own lens, light will enter each ommatidium instead of using a single entrance point. The individual light receptors behind each lens are then turned on and off due to a series of changes in the light intensity during mov ...
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Insect Morphology
Insect morphology is the study and description of the morphology (biology), 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 (called tagmata) (head, thorax, and abdomen), three pairs of legs, and mouthparts located ''outside'' of the #Head, head capsule. This position of the mouthparts divides them from their closest relatives, the non-insect Hexapoda, hexapods, which include Protura, Diplura, and Collembola. There is enormous variation in body structure amongst insect species. Individuals can range from 0.3 mm (fairyfly, fairyflies) to 30 cm across (Thysania agrippina, great owlet moth); have no eyes or many; well-developed wings or none; and legs modified for running, jumping, swimming, or even digging. These modifications allow insects to occupy almost every ...
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Trachea
The trachea (: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals' lungs. The trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea, the cricoid cartilage attaches it to the larynx. The trachea is formed by a number of horseshoe-shaped rings, joined together vertically by overlying annular ligaments of trachea, ligaments, and by the trachealis muscle at their ends. The epiglottis closes the opening to the larynx during swallowing. The trachea begins to form in the second month of embryo development, becoming longer and more fixed in its position over time. Its epithelium is lined with columnar epithelium, column-shaped cells that have hair-like extensions called cilia, with scattered goblet cells that produce protective mucins. The trachea can be affected by inflammation or infection, usua ...
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Spiracle (arthropods)
A spiracle or stigma is the opening in the exoskeletons of insects, myriapods, velvet worms and many arachnids to allow air to enter the trachea. Insect respiratory system differs from vertebrates'. The circulatory system plays a relatively minor role in circulating oxygen and removing carbon dioxide; instead, trachea and air sacs in the insect body allow direct gas exchange, and these tracheal tubes eventually connect to the external environment via spiracles. In most species, the spiracles are controlled by motor neurons in the central nervous system. It can be opened and closed in an efficient manner to admit air while minimizing associated physiological costs, such as water loss during respiration. Many sensory stimuli can affect the control of spiracles in insects, e.g. chemosensory (carbon dioxide, oxygen, etc.) or mechanosensory (sound, touch, etc.). It has been shown that during metabolically intensive behaviors, such as flight, insects can dynamically modulate the spir ...
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Respiratory System Of Insects
An insect's respiratory system is the system with which it introduces respiratory gases to its interior and performs gas exchange. Air enters the respiratory systems of insects through a series of external openings called Spiracle (arthropods), spiracles. These external openings, which act as muscular valves in some insects, lead to the internal respiratory system, a densely networked array of tubes called Trachea#Invertebrates, tracheae. This network of transverse and longitudinal tracheae equalizes pressure throughout the system. It is responsible for delivering sufficient Dioxygen in biological reactions, oxygen (O2) to all cells of the body and for removing carbon dioxide (CO2) that is produced as a waste product of cellular respiration. The respiratory system of insects (and many other arthropods) is separate from the hemolymph, circulatory system. Structure of the spiracle Insects have spiracles on their exoskeletons to allow air to enter the trachea. In insects, th ...
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Oviparous
Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings known as hatchlings with little or no embryonic development within the mother. This is the reproductive method used by most animal species, as opposed to viviparous animals that develop the embryos internally and metabolically dependent on the maternal circulation, until the mother gives birth to live juveniles. Ovoviviparity is a special form of oviparity where the eggs are retained inside the mother (but still metabolically independent), and are carried internally until they hatch and eventually emerge outside as well-developed juveniles similar to viviparous animals. Modes of reproduction The traditional modes of reproduction include oviparity, taken to be the ancestral condition, traditionally where either unfertilised oocytes or ...
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Ventral Nerve Cord
The ventral nerve cord is a major structure of the invertebrate central nervous system. It is the functional equivalent of the vertebrate spinal cord. The ventral nerve cord coordinates neural signaling from the brain to the body and vice versa, integrating sensory input and locomotor output. Because arthropods have an open circulatory system, decapitated insects can still walk, groom, and mate — illustrating that the circuitry of the ventral nerve cord is sufficient to perform complex motor programs without brain input. Structure The ventral nerve cord runs down the ventral ("belly", as opposed to back) plane of the organism. It is made of nervous tissue and is connected to the brain. Ventral nerve cord neurons are physically organized into neuromeres that process signals for each body segment. Anterior neuromeres control the anterior body segments, such as the forelegs, and more posterior neuromeres control the posterior body segments, such as the hind legs. Neurom ...
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Insect Brain
The supraesophageal ganglion (also "supraoesophageal ganglion", "arthropod brain" or "microbrain") is the first part of the arthropod, especially insect, central nervous system. It receives and processes information from the first, second, and third Metamerism (biology), metameres. The supraesophageal ganglion lies Dorsum (anatomy), dorsal to the esophagus and consists of three parts, each a pair of ganglia that may be more or less pronounced, reduced, or fused depending on the genus (biology), genus: * The ''protocerebrum'', associated with the arthropod eye, eyes (Eye#Compound eyes, compound eyes and ocelli). Directly associated with the eyes is the optic lobe (arthropod), optic lobe, as the visual center of the brain. * The ''deutocerebrum'' processes sensory information from the Antenna (biology), antennae. It consists of two parts, the antennal lobe and the dorsal lobe. The dorsal lobe also contains motor neurons which control the antennal muscles. * The ''tritocerebrum'' i ...
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Nervous System
In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. Nervous tissue first arose in Ediacara biota, wormlike organisms about 550 to 600 million years ago. In Vertebrate, vertebrates, it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers, or axons, that connect the CNS to every other part of the body. Nerves that transmit signals from the brain are called motor nerves (efferent), while those nerves that transmit information from the body to the CNS are called sensory nerves (aff ...
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Species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour, or ecological niche. In addition, palaeontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomen". The first part of a binomen is the name of a genus to which the species belongs. The second part is called the specific name (zoology), specific name or the specific ...
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