(ZOOCR)POLYMORPHISM IN COELENTERATA. (Dr. Girish Chandra ). The occurrence of more than one type of structurally . 10 Jul POLYMORPHISM IN COELENTERATES The presence of polymorphism in cnidarians is one of their characteristic features. It is defined as. The common polymorphic siphonophores are Halistemna, Physalia, Velella and OF POLYMORPHISM After studying the polymorphism in coelenterates the.

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It is called ‘Coenosarcai stalk’. It floats on the top of the sea water. This siphonophore organism will show polymorphic lolymorphism. They take up different functions.

Submerged bank theory This theory states that both barrier reefs and atolls grew upon pre-existing flat surfaces. Zygote develops into a free swimming ciliated planula larva which polymorphism in coelenterates down and metamorphosis into a young coral polyp.

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Dactylozooids which are used for defence are polyps without mouth and usually with a long basal tentacle. They may polymorphism in coelenterates also called as feelers or palpons. It has a long tentacle at its coelentertes.

The coenosaroal stalk below the swimming bells is siphanosome. In Halistemma a bract covers the zooids of a cormidium.

Gonozooids produce medusae called gonophores. Different functions are assigned to different individuals, rather than to parts or organs of one individual. Some forms like Plumularia, are trimorphic. The polymorphism in coelenterates Hydrozoa of phylum Coelenterata includes a large number of colonial species that contain more than one form of individuals which are called zooids Coelenterates have two basic zooids, polyp and medusa.


Polymorphism in coelenterates of coral polyp: Tahir Habib Tunio 31 January at These are functionally non-feeding and defensive polyps bearing batteries of nematocysts. Coelenterates having more than three types of individuals are called polymorphic, e. It is big and colourful.


Simplest and commonest pattern of polymorphism is exhibited by many hydrozoan colonies like Obelia, Tubularia, Campanularia etc. These individual zooids are attached to a common stalk called Coenosarc. Polymorphic tendency in siphonophora animals The polymorphic tendency reached its peak in coelenterate organisms belonging to order ‘Siphanophora’ of class ‘Hydrozoa’.

It is a leaf of structure. Hydractinia which has five types of zooids, each performing polymorphism in coelenterates specialized function. Coelenterares branches are polymrphism called tentilla.

Phyllozooid or bract, polymorphism in coelenterates leaf-like and studded with nematocysts, serving for protection of other zooids. It contains gas chambers polymorphism in coelenterates.

Newer Post Older Post Home. Nectophore or nectocalyx or swimming zooid with a muscular bell without manubrium or tentacles.

Thus arises the alternation of generation or metagenesis. Pharynx or stomodaeum is short and without siphonoglyphs. Extensive coral growth occurred on polymorphism in coelenterates flat surface which got submerged in the water with the passage of time.

Polymorphism: Definition, Causes and Significance | Cnidarians

Gastrozooids are for feeding, spiral dactylozooids for protection, long tentaculozooids polymorphism in coelenterates sensory function. Lastly, corals act as affective buffers against erosion and storms occurring in the sea thus help in preventing polymorphism in coelenterates disaster.

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They are called Palpons, feelers or tasters. Modifications of Medusa Nectophore or nectocalyx or swimming bell is a medusa modified for sexual reproduction. Many of the corals are precious stones which are used in making jewelry and have aesthetic value. Sometimes both fringing reefs and barrier reefs may join each other at the bottom of the sea.

They are separated by partitions. corlenterates


The medusoid individuals are of the following types 1. As regards polymorphism in coelenterates origin of polymorphism in cnidarians, the following theories have been advanced: Study Notes on Amoeba Proteus.

These bells are modified Medusae. There are three types of coral reefs: These forms or zooids are developed from polyps or medusae. Ppolymorphism order Siphonophorasuch as Diphyes, Halistemmia, Stephalia and Physalia, zooids are so much modified that they appear like organs of a single body rather than individuals of a colony. BiologyArticles on AnimalsCnidarians polymorphism in coelenterates, Polymorphism.

Polymorphism is intimately associated with life-history.