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Stony Corals. Giordano Soto Marine pd:1 ext.credit ppt. 1/27/14. Taxonomy. Kingdom: Animalia Phylum: Cnidaria Class: Anthozoa Subclass: Hexacorallia Order: Scleractinia. Scleractinia. also called stony corals, are marine corals that generate a hard skeleton
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Stony Corals Giordano Soto Marine pd:1 ext.credit ppt. 1/27/14
Taxonomy Kingdom: Animalia Phylum: Cnidaria Class: Anthozoa Subclass: Hexacorallia Order: Scleractinia
Scleractinia also called stony corals, are marine corals that generate a hard skeleton Much of the framework of modern coral reefs is formed by scleractinians. Stony corals numbers are expected to decline due to the effects of global warming
Groups of Scleractinia There are two groups of Scleractinia: Compound corals live in colonies in clear, oligotrophic, shallow tropical waters; they are the world's primary reef-builders. Solitary corals are found in all regions of the oceans and do not build reefs. In addition to living in tropical waters some solitary corals live in temperate, polar waters, or below the *photic zone down to 6,000 metres (20,000 ft) *Photic zone- The photic zone, euphotic zone, or sunlight zone is the depth of the water in a lake or ocean that is exposed to sufficient sunlight for photosynthesis to occur
Groups of Scleractinia There are two groups of Scleractinia: Compound corals live in colonies in clear, oligotrophic, shallow tropical waters; they are the world's primary reef-builders. Solitary corals are found in all regions of the oceans and do not build reefs. In addition to living in tropical waters some solitary corals live in temperate, polar waters, or below the *photic zone down to 6,000 metres (20,000 ft) *Photic zone- The photic zone, euphotic zone, or sunlight zone is the depth of the water in a lake or ocean that is exposed to sufficient sunlight for photosynthesis to occur
Composition Stony corals may be solitary or compound. Most have very small polyps, ranging from 1 to 3 millimeters (0.04 to 0.1 in) in diameter, although some solitary species may be as large as 25 centimeters (9.8 in). The most common forms include conical and horn-shaped polyps. Colonies can reach considerable size, consisting of a large number of individual polyps.
Skeleton The skeleton of an individual scleractinian polyp is known as a corallite. It is secreted by the epidermis of the lower part of the body, and initially forms a cup surrounding this part of the polyp. The interior of the cup contains radially aligned plates, or septa, projecting upwards from the base. Each of these plates is flanked by a pair of thin sheets of living tissue termed mesenteries.
Secondary Structures In scleractinians, there are two main secondary structures: Stereome is an adherent layer of secondary tissue, which covers the septal surface. It consists of transverse bundles of aragonitic needles and protects the polyps. However, its function can be nullified by the thickening of the septa itself. Coenosteum is a perforated complex tissue that separates individual corallites in a compound scleractinian.
At the beginning of Scleractinia’s development, four groups with different microstructure can distinguished. These are:
Pachytecal: Corals having very thick walls and rudimentary septa. This is the group which probably originated from Rugosa corals. Thick Trabecular: Corals with septa built from thick structures, resembling little beams, called trabecules. Minitrabecular: Corals with septa built from thin trabecules. Fascilcular or non-trabecular: Corals with septa not built from trabecules, but from columns composed of bunches of aragonite fibres.
Reproduce Stony corals can reproduce both sexually and asexually. Many species have separate sexes, but others are hermaphroditic. Sexual reproduction results in the birth of a free-swimming planula larva that eventually settles to form a polyp. In colonial species, this initial polyp then repeatedly divides asexually, to give rise to the entire colony.
Reproduce (cont.) There are two types of budding: intratentacular and extratentacular. In an intratentacular budding, polyps are divided by simple fission across the stomodaeum, and each bud retains part of the original stomodaeum and regenerates the rest. Extratentacular budding takes place outside the tentacular ring of the parent. These daughter buds do not share any part in the functions within the parent scleractinians as do the products of intratentacular budding.
So Aggresive Corals have developed several specialized mechanisms for protection and competition with other corals. These include: sweeper tentacles mesenterial filaments terpenoid compounds (Soft Coral)
Sweeper Tentacles Sweeper tentacles are the most common defense mechanisms in the hard corals. These mouthless elongated tentacles form the outermost portion of the coral colony and act as a "patrol" along the periphery. When a sweeper tentacle encounters a competing coral, it may attack the competing coral and literally "burn" the offending coral to the point of either killing it or severely damaging it. This "burning" is the result of specialized stinging cells called nematocysts that are present in these tentacles
Mesenterial Filaments several hard coral species can produce mesenterial filaments (also termed mesenteric filaments) from their stomachs. Corals of the genera Favia, Favites, Scolymia, Pavona, and Cynarina all have this capacity. These filaments can kill or devour other coral polyps through a process similar to digestion. Some corals even have the capacity to produce both sweeper tentacles and mesenterial filaments, enabling them to fight a battle on several ''Fronts''
~~~Brain Coral~~~ ~ stony coral~
Taxonomy 2 (Brain Coral) Kingdom: Animalia Phylum: Cnidaria Class: Anthozoa Order: Scleractinia Suborder: Faviina Family: Faviidae
Brain Coral... Brain coral is a common name given to corals in the family Faviidae so called due to their generally spheroid shape and grooved surface which resembles a brain. Each head of coral is formed by a colony of genetically identical polyps which secrete a hard skeleton of calcium carbonate this makes them important coral reef builders like other stony corals in the order Scleractinia.
Brain corals extend their tentacles to catch food at night. During the day, the brain corals use their tentacles for protection by wrapping them over the grooves on their surface. The surface is hard and offers good protection against fish or hurricanes. Branching corals, such as staghorn corals, grow more rapidly, but those are more vulnerable to storm damage.
Like other genera of corals, brain corals feed on small drifting animals and also receive nutrients provided by the algae which live within their tissues. The behavior of one of the most common genera, Favia, is semi-aggressive it will sting other corals with its extended sweeper tentacles during the night. The genus and species has not been defined through the scientific classification segment.
Pictures http://www.flickr.com/photos/myfwc/6077230774/in/set-72157627509643448/
ENDBibliography http://www.arkive.org/brain-coral/platygyra-daedalea/ http://en.wikipedia.org/wiki/Brain_coral http://www.arkive.org/brain-coral/platygyra-daedalea/ http://www.coexploration.org/bbsr/coral/html/body_basic_coral_biology.html http://www.flickr.com/photos/myfwc/6077230774/in/set-72157627509643448/ http://upload.wikimedia.org/wikipedia/commons/3/30/Staghorn-coral-1.jpg
Sunray Lettuce Corral ( Helioseris cucullata (formerly Leptoseris))
