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・ Evolve (Endo album)
・ Evolve (EP)
・ Evolve (Eye Empire album)
・ Evolve (professional wrestling)
・ Evolve (song)
・ Evolve (TV series)
・ Evolve (video game)
・ Evolution of photosynthesis
・ Evolution of primates
・ Evolution of Quartz C-axis Pole Figures during Dynamic Recrystallization
・ Evolution of reptiles
・ Evolution of schizophrenia
・ Evolution of sexual reproduction
・ Evolution of sirenians
・ Evolution of snake venom
Evolution of spiders
・ Evolution of tetrapods
・ Evolution of the brain
・ Evolution of the cochlea
・ Evolution of the Daleks
・ Evolution of the Dutch Empire
・ Evolution of the eye
・ Evolution of the French Empire
・ Evolution of the horse
・ Evolution of the opposed cerebral hemisphere control
・ Evolution of the opposite cerebral hemisphere control
・ Evolution of the Portuguese Empire
・ Evolution of the Spirit
・ Evolution of the Vertebrates
・ Evolution of timpani in the 18th and 19th centuries


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Evolution of spiders : ウィキペディア英語版
Evolution of spiders
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The evolution of spiders has been going on for at least 400 million years, since the first true spiders (thin-waisted arachnids) evolved from crab-like chelicerate ancestors.
Today, there are 42,473 described spider species within the diverse phylum of arthropods.
Major developments in spider evolution include the development of spinnerets and silk secretion.
==Early spider-like arachnids==
Among the oldest known land arthropods are Trigonotarbids, members of an extinct order of spider-like arachnids.
Trigonotarbids share many superficial characteristics with spiders, including a terrestrial lifestyle, respiration through book lungs, and walked on eight legs, with a pair of leg-like pedipalps near the mouth and mouth parts. Arguments still remain open as to whether they possessed the ability to create silk. This had been a popular thought for quite some time, until an unpublished fossil was described with distinct microtubercles on its hind legs, akin to those used by spiders to direct and manipulate their silk.
Regardless, trigonotarbids are not considered true spiders, but are instead accepted as an independent group of arachnids not directly ancestral to modern spiders.

抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)
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