Endoskeleton

An endoskeleton (From Greek ἔνδον, éndon = "within", "inner" + σκελετός, skeletos = "skeleton") is an internal support structure of an animal, composed of mineralized tissue.

Endoskeleton of a swordfish

Overview

An endoskeleton is a skeleton that is on the inside of a body. The endoskeleton develops within the skin or in the deeper body tissues. The vertebrate endoskeleton is basically made up of two types of tissues (bone and cartilage). During early embryonic development the endoskeleton is composed of notochord and cartilage. The notochord in most vertebrates is replaced by the vertebral column and cartilage is replaced by bone in most adults. In three phyla and one subclass of animals, endoskeletons of various complexity are found: Chordata, Echinodermata, Porifera, and Coleoidea. An endoskeleton may function purely for support (as in the case of sponges), but often serves as an attachment site for muscle and a mechanism for transmitting muscular forces. A true endoskeleton is derived from mesodermal tissue. Such a skeleton is present in echinoderms and chordates. The poriferan 'skeleton' consists of microscopic calcareous or siliceous spicules or a spongin network. The Coleoidae do not have a true endoskeleton in the evolutionary sense; there, a mollusk exoskeleton evolved into several sorts of internal structure, the "cuttlebone" of cuttlefish being the best-known version. Yet they do have cartilaginous tissue in their body, even if it is not mineralized, especially in the head, where it forms a primitive cranium. The endoskeleton gives shape, support, and protection to the body and provides a means of locomotion.

HumanAustralopithecusNeanderthalBaboonColobinaeGorillaWild boarCattleLionHorseElephantGoatHippopotamidaeCamelKangarooAntelopeWalrusBatWhaleEagleChickenRoosterToucanCasuariidaePenguinCraneBirdSnakeCrotalinaeBoa constrictorCrocodileLizardTurtleFrogSalamanderSturgeonTriggerfishBatoideaEsox
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gollark: The toy version in said Minecraft computer mod just works off the distances directly, since those are provided by the mod's wireless transceivers.
gollark: Ah yes, an asteroid firing a laser at the Earth which is somehow visible in space which is reflected off at a strange angle.
gollark: Doesn't it work out the distances from timing differences or something rather than signal strength or whatever?

See also

References
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