Changes

==Origin==

==Origin==

[[Latin]] ''insectum'', from neuter of ''insectus'', past participle of ''insecare'' to cut into, from ''in''- + ''secare'' to cut

[[Latin]] ''insectum'', from neuter of ''insectus'', past participle of ''insecare'' to cut into, from ''in''- + ''secare'' to cut

*[http://en.wikipedia.org/wiki/17th_century 1601]

*[https://en.wikipedia.org/wiki/17th_century 1601]

The [[word]] ''insect'' dates back to 1600, from the [[Latin]] word ''insectum'' meaning "with a notched or divided [[body]]," [[literally]] "cut into," from neuter plural of ''insectare'' "to cut into, to cut up," from ''in''- "into" + ''secare'' "to cut"; from the [[fact]] that insects are "cut into" three sections. The word created by [http://en.wikipedia.org/wiki/Pliny_the_Elder Pliny the Elder]'s loan-[[translation]] of the [[Greek]] word [http://en.wiktionary.org/wiki/%E1%BC%94%CE%BD%CF%84%CE%BF%CE%BC%CE%BF%CF%82 ἔντομος] or "insect" (as in [http://en.wikipedia.org/wiki/Entomology entomology]), which was Aristotle's term for this [[class]] of life, also in reference to their "notched" bodies, first documented in [[English]] in 1601 in Holland's translation of Pliny. Translations of Aristotle's term also form the usual word for "insect" in Welsh (''trychfil'', from ''trychu'' "cut" + ''mil'' "animal"), Serbo-Croatian (''zareznik'', from ''rezati'' "cut"), Russian (насекомое ''nasekomoe'', from ''sekat'' "cut"), etc.

The [[word]] ''insect'' dates back to 1600, from the [[Latin]] word ''insectum'' meaning "with a notched or divided [[body]]," [[literally]] "cut into," from neuter plural of ''insectare'' "to cut into, to cut up," from ''in''- "into" + ''secare'' "to cut"; from the [[fact]] that insects are "cut into" three sections. The word created by [https://en.wikipedia.org/wiki/Pliny_the_Elder Pliny the Elder]'s loan-[[translation]] of the [[Greek]] word [https://en.wiktionary.org/wiki/%E1%BC%94%CE%BD%CF%84%CE%BF%CE%BC%CE%BF%CF%82 ἔντομος] or "insect" (as in [https://en.wikipedia.org/wiki/Entomology entomology]), which was Aristotle's term for this [[class]] of life, also in reference to their "notched" bodies, first documented in [[English]] in 1601 in Holland's translation of Pliny. Translations of Aristotle's term also form the usual word for "insect" in Welsh (''trychfil'', from ''trychu'' "cut" + ''mil'' "animal"), Serbo-Croatian (''zareznik'', from ''rezati'' "cut"), Russian (насекомое ''nasekomoe'', from ''sekat'' "cut"), etc.

<center>For lessons on the [[topic]] of '''''Insects''''', follow [https://nordan.daynal.org/wiki/index.php?title=Category:Insects '''''this link'''''].</center>

<center>For lessons on the [[topic]] of '''''Insects''''', follow [https://nordan.daynal.org/wiki/index.php?title=Category:Insects '''''this link'''''].</center>

==Definitions==

==Definitions==

*1a : any of numerous small [http://en.wikipedia.org/wiki/Invertebrate invertebrate] animals (as spiders or centipedes) that are more or less obviously segmented —not used [[technically]]  

*1a : any of numerous small [https://en.wikipedia.org/wiki/Invertebrate invertebrate] animals (as spiders or centipedes) that are more or less obviously segmented —not used [[technically]]  

:b : any of a class (Insecta) of [http://en.wikipedia.org/wiki/Arthropods arthropods] (as bugs or bees) with well-defined head, thorax, and abdomen, only [[three]] pairs of legs, and typically one or two pairs of wings

:b : any of a class (Insecta) of [https://en.wikipedia.org/wiki/Arthropods arthropods] (as bugs or bees) with well-defined head, thorax, and abdomen, only [[three]] pairs of legs, and typically one or two pairs of wings

*2: a trivial or contemptible [[person]]  

*2: a trivial or contemptible [[person]]  

==Description==

==Description==

'''Insects''' (from [[Latin]] ''insectum'', a calque of [[Greek]] ἔντομον [''éntomon''], "cut into sections") are a class of living [[creatures]] within the [http://en.wikipedia.org/wiki/Arthropod arthropods] that have a [http://en.wikipedia.org/wiki/Chitin chitinous] [http://en.wikipedia.org/wiki/Exoskeleton exoskeleton], a three-part body (head, thorax, and abdomen), three pairs of jointed legs, compound eyes, and two antennae. They are among the most [[diverse]] groups of [[animals]] on [[the planet]], including more than a million described [[species]] and represent more than half of all known living [[organisms]]. The number of extant species is estimated at between six and ten million and potentially represent over 90% of the differing [http://en.wikipedia.org/wiki/Metazoa metazoan] life forms on [[Earth]]. Insects may be found in nearly all [[environments]], although only a small number of species occur in the [[oceans]], a habitat [[dominated]] by another arthropod group, the [http://en.wikipedia.org/wiki/Crustacean crustaceans].

'''Insects''' (from [[Latin]] ''insectum'', a calque of [[Greek]] ἔντομον [''éntomon''], "cut into sections") are a class of living [[creatures]] within the [https://en.wikipedia.org/wiki/Arthropod arthropods] that have a [https://en.wikipedia.org/wiki/Chitin chitinous] [https://en.wikipedia.org/wiki/Exoskeleton exoskeleton], a three-part body (head, thorax, and abdomen), three pairs of jointed legs, compound eyes, and two antennae. They are among the most [[diverse]] groups of [[animals]] on [[the planet]], including more than a million described [[species]] and represent more than half of all known living [[organisms]]. The number of extant species is estimated at between six and ten million and potentially represent over 90% of the differing [https://en.wikipedia.org/wiki/Metazoa metazoan] life forms on [[Earth]]. Insects may be found in nearly all [[environments]], although only a small number of species occur in the [[oceans]], a habitat [[dominated]] by another arthropod group, the [https://en.wikipedia.org/wiki/Crustacean crustaceans].

The life [[cycles]] of insects vary but most hatch from eggs. Insect [[growth]] is constrained by the inelastic exoskeleton and development involves a series of [http://en.wikipedia.org/wiki/Moulting molts]. The immature [[stages]] can differ from the adults in [[structure]], [[habit]] and [[habitat]] and can include a passive [http://en.wikipedia.org/wiki/Pupa pupal] stage in those groups that undergo complete [[metamorphosis]]. Insects that undergo incomplete metamorphosis lack a pupal stage and adults [[develop]] through a series of [http://en.wikipedia.org/wiki/Nymph_(biology) nymphal] stages. The higher level [[relationship]] of the [http://en.wikipedia.org/wiki/Hexapoda hexapoda] is unclear. [[Fossilized]] insects of enormous size have been found from the [http://en.wikipedia.org/wiki/Paleozoic Paleozoic Era], including giant dragonflies with wingspans of 55 to 70 cm (22–28 in). The most [[diverse]] insect groups appear to have coevolved with flowering [[plants]].

The life [[cycles]] of insects vary but most hatch from eggs. Insect [[growth]] is constrained by the inelastic exoskeleton and development involves a series of [https://en.wikipedia.org/wiki/Moulting molts]. The immature [[stages]] can differ from the adults in [[structure]], [[habit]] and [[habitat]] and can include a passive [https://en.wikipedia.org/wiki/Pupa pupal] stage in those groups that undergo complete [[metamorphosis]]. Insects that undergo incomplete metamorphosis lack a pupal stage and adults [[develop]] through a series of [https://en.wikipedia.org/wiki/Nymph_(biology) nymphal] stages. The higher level [[relationship]] of the [https://en.wikipedia.org/wiki/Hexapoda hexapoda] is unclear. [[Fossilized]] insects of enormous size have been found from the [https://en.wikipedia.org/wiki/Paleozoic Paleozoic Era], including giant dragonflies with wingspans of 55 to 70 cm (22–28 in). The most [[diverse]] insect groups appear to have coevolved with flowering [[plants]].

Insects typically move about by walking, flying or occasionally swimming. As it allows for rapid yet [[stable]] movement, many insects adopt a tripedal gait in which they walk with their legs [[touching]] the ground in alternating triangles. Insects are the only invertebrates to have evolved flight. Many insects spend at least part of their life underwater, with [http://en.wikipedia.org/wiki/Larval larval] [[adaptations]] that include [http://en.wikipedia.org/wiki/Gill gills] and some adult insects are aquatic and have adaptations for swimming. Some [[species]], like [http://en.wikipedia.org/wiki/Gerridae water striders], are capable of walking on the [[surface]] of [[water]]. Insects are mostly [[solitary]], but some insects, such as certain bees, ants, and termites are [[social]] and live in large, well-[[organized]] colonies. Some insects, like [http://en.wikipedia.org/wiki/Earwig earwigs], show [[maternal]] care, guarding their eggs and young. Insects can [[communicate]] with each other in a [[variety]] of ways. Male moths can sense the [http://en.wikipedia.org/wiki/Pheromone pheromones] of female moths over distances of many kilometers. Other species [[communicate]] with sounds: crickets [http://en.wikipedia.org/wiki/Stridulation stridulate], or rub their wings together, to attract a mate and repel other males. [http://en.wikipedia.org/wiki/Firefly Lampyridae] in the [http://en.wikipedia.org/wiki/Beetle beetle order Coleoptera] communicate with [[light]].

Insects typically move about by walking, flying or occasionally swimming. As it allows for rapid yet [[stable]] movement, many insects adopt a tripedal gait in which they walk with their legs [[touching]] the ground in alternating triangles. Insects are the only invertebrates to have evolved flight. Many insects spend at least part of their life underwater, with [https://en.wikipedia.org/wiki/Larval larval] [[adaptations]] that include [https://en.wikipedia.org/wiki/Gill gills] and some adult insects are aquatic and have adaptations for swimming. Some [[species]], like [https://en.wikipedia.org/wiki/Gerridae water striders], are capable of walking on the [[surface]] of [[water]]. Insects are mostly [[solitary]], but some insects, such as certain bees, ants, and termites are [[social]] and live in large, well-[[organized]] colonies. Some insects, like [https://en.wikipedia.org/wiki/Earwig earwigs], show [[maternal]] care, guarding their eggs and young. Insects can [[communicate]] with each other in a [[variety]] of ways. Male moths can sense the [https://en.wikipedia.org/wiki/Pheromone pheromones] of female moths over distances of many kilometers. Other species [[communicate]] with sounds: crickets [https://en.wikipedia.org/wiki/Stridulation stridulate], or rub their wings together, to attract a mate and repel other males. [https://en.wikipedia.org/wiki/Firefly Lampyridae] in the [https://en.wikipedia.org/wiki/Beetle beetle order Coleoptera] communicate with [[light]].

[[Humans]] regard certain insects as [http://en.wikipedia.org/wiki/Pest_(organism) pests] and attempt to [[control]] them using insecticides and a host of other [[techniques]]. Some insects damage crops by feeding on sap, leaves or fruits, a few bite humans and livestock, alive and dead, to feed on [[blood]] and some are capable of transmitting [[diseases]] to humans, pets and livestock. Nevertheless, without insects to pollinate flowers, the [[human]] race would soon run out of [[food]] because many of the crop plants that we rely on would not be able to [[reproduce]]. Many other insects are considered [[ecologically]] beneficial as predators and a few provide direct [[economic]] benefit. [http://en.wikipedia.org/wiki/Silkworm Silkworms] and bees have been used extensively by humans for the production of silk and honey, respectively.[http://en.wikipedia.org/wiki/Insects]

[[Humans]] regard certain insects as [https://en.wikipedia.org/wiki/Pest_(organism) pests] and attempt to [[control]] them using insecticides and a host of other [[techniques]]. Some insects damage crops by feeding on sap, leaves or fruits, a few bite humans and livestock, alive and dead, to feed on [[blood]] and some are capable of transmitting [[diseases]] to humans, pets and livestock. Nevertheless, without insects to pollinate flowers, the [[human]] race would soon run out of [[food]] because many of the crop plants that we rely on would not be able to [[reproduce]]. Many other insects are considered [[ecologically]] beneficial as predators and a few provide direct [[economic]] benefit. [https://en.wikipedia.org/wiki/Silkworm Silkworms] and bees have been used extensively by humans for the production of silk and honey, respectively.[https://en.wikipedia.org/wiki/Insects]

[[Category: Zoology]]

[[Category: Zoology]]