What is in the biology of exoskeletons?

In biology, exoskelette refers to a chitinous or calcified outer skeleton used by numerous animal taxa for structural support and defense against predators. Exoskeletons can be contrasted with endoskeletons (internal skeletons) that people and other vertebrates have. In the animal world, exoskeletons are much more common than endoskeletons - millions of species have exoskeletons, while only a few thousand have endoskeletons. It is assumed that 18 lines have developed calcified exoskeletons themselves, while others developed chitinous and other types of exoskeletons. Exoskeletons are particularly popular in arthropods and molluscs, with two of the largest existing animals exist. Paleontologists did not agree on what was actually Cloudina , but the current popular estimate of it was Polychhaete - sea Annelid. Cloudina is the first of the small fauna Shelly, numerous animals that developed at the beginning of the Cambrian period 545 million years ago. Look smallShelly's fauna refers to the beginning of the Cambrians.

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exoskelette has a number of advantages for the body or line that develops - primarily provides protection. It is obviously one of the simplest defense mechanisms that develop, and probably appeared on the earliest days of animal predation. It seems that even the first exoskeletons in fossil records have boreholes, which testifies to predation. Many of the first animals that developed exoskeletons were apparently molluscs. kimberella , a mollusk similar to creatures that existed for a full 555 million years, had a hard shell, but it was not mineralized, so it was not a real exoskeleton. Mineralized exoskeletons would appear in large numbers shortly thereafter.

In addition to predation protection, the exoskeleton provides structural support to the animal. In some cases, this allows them to achieve a greater maximum size than it could be achieved differently. For example dUnkelosteus , 6 m (20 ft) Fish, which is considered one of the most feared marine hunters, was Placoderm, an animal whose large size was partly possible to cover the head. Although vertebrates are generally greater than invertebrates (partly because they control the Earth), medium -sized invertebrates with exoskeletons are generally better than those who are not, as evidenced by the greatest phyla in the animal kingdom, arthropods.