The biocenosis of a coral reef in the systematic relation is exclusively various and presented by many hundreds of species of plants and animals as producers, and the konsument forming a uniform food (trophic) chain. It is uniform, the most active and at the same time the most difficult ecosystem on Earth. At the same time it the most ancient of all known ecosystems and the steadiest.
The research Pocillopora damicornis – the main coral-rifostroitelya of the Hawaiian Islands showed that the maximum growth of these polipnyak proceeds at 26zs, and minimum – at 21-22zs; on shoal of a colony were bugrovidny and grew quicker, and in the depth of a reef zone – column and grew more slowly.
For corals are pernicious desalting (for example, tropical heavy rains during outflow, drainage, hurricanes – after such accidents the reef can be restored years for thirty, and even more. Some fishes, crabs and other organisms eat corals.
Coral polyps, or simply corals (Anthozoa) which majority is characterized by existence of the skeleton put by fibers of aragonite or calcite. Their reliable most ancient representatives are known since the Ordovician, but it is possible, they appeared earlier.
External wall of a coral multilayered, usually its external layer ( it is covered with thin cross rugosity, as if signs of increase (rugama); from here and name of the whole group of ancient corals of a rugoza. The goloteka can sometimes be the general for all polipnyak, covering it outside from below and from sides. The following layer – an epiteka, is covered with longitudinal edges which correspond to either septa, or intervals between them.
Reef – the special form of an underwater relief, a carbonate design on shelf shoal formed emitting lime rifostroyashchy (differently – germatipny) by organisms that in total with a complex of physiographic parameters also defines specificity of a reef ecosystem.
For corals so-called pseudo-colonies are very characteristic – Paleozoic rugoza and some tabulyata are in this regard especially typical. Pseudo-colonial construction arises when consecutive repeated budding leads to formation of the difficult units consisting from densely or leaky adjoining corals of absolutely similar structure and always deprived a tsenosarka i.e. in which all individuals are identical both morphologically and is functional. Sometimes walls of korallit are penetrated by a time, connected by tubules, i.e. among themselves. This phenomenon is called as a kommunikatnost, and it is possible to claim that the kommunikatnost is peculiar to all corals.
At modern skleraktiniya, as well as at ancient corals, the soft body is on a surface, each polyp sits in small deepening (; its growth happens by consecutive formation of bazalny basic elements of a skeleton up (the bottoms and other structures of the same origin), and as a result all grows up. Thus, a skeleton of all these corals – external. At other their group – at eight-beam corals (oktokorall or altsionariya) – the skeleton is put by specific elements – the spikula which are formed in a mesogley therefore it also is called internal or mezoglealny. Growing together among themselves, spikula make the general axial skeletal framework.
Actually corals – exclusively sea animals. They can be single and colonial. A body of each polyp (zooides has a sack appearance with a slit-like opening – a mouth which is surrounded with feelers. From a mouth to an internal cavity there is a short flattened throat. The internal cavity is divided by vertical partitions (mezenteriya) which are not connecting in the center of a cavity among themselves. A wall, as well as at all other coelenterates, three-layer.
The paleontology has not organisms, but their remains which can remain in a fossil state – the hardened skeletons, prints, molds, kernels. In this regard corals represent very valuable object for paleontologic researches as the majority of them always formed a strong skeleton.
Gidroidny polyps (Hydrozoa; treats them our fresh-water hydras. Single and colonial animals, which separate individuals can have a form as polyp, and a jellyfish, possessing a pseudo-chitinous or limy skeleton. Are known since the Cambrian, and it is possible, and from the Precambrian, exist and nowadays.