Hi, now we are going to discuss characteristics and classification of coelenterata in which we will discuss their general characteristics features and their classification along with their examples of each category.
Table of Contents
Basic Idea About Coelenterata:
Members of coelenterata are mostly observed in aquatic environments, especially in marine environments; they grow abundantly and they do not show movement; generally they attach to the floor of water bodies and search for food. They live in water bodies with a large number of individuals together in the form of colonies or maybe live in solitarily.
They are multicellular organisms but their cells are specialised for different purposes and give rise to different types of tissues who have some special functions so they show tissue level of organisation. The Hydra we see in water bodies and sea anemone generally observed in oceanic floor are examples of kingdom coelenterata.
Characteristics of Coelenterata:
Coelenterata are Aquatic Animals:
The members of coelenterata are aquatic and it helps them to get sufficient food through water flow and as they can not move rapidly so it is impossible to chase their prey and catch them but in water bodies they can easily find their food and water act as medium.
Tissue Level of Organisation:
In coelenterata the body is made by a large number of cells so they are multicellular but their cells are differentiated for different functions and form groups of cells which have similar functions so they show tissue level of organisation.
They Have Tentacles:
In coelenterata as they can not move rapidly and are mostly attached with the floor of water bodies so they need some structure which can catch their prey and this function is done by the tentacles present around their mouth cavity which catch the prey and pass into their mouth.
Coelenterata are Diploblastic:
They are diploblastic so during embryonic development only two germ layer give rise to all types of cells in their body and the two layer are known as ectoderm and endoderm, ectoderm form the outer layer of their body while the endoderm is responsible making the inner layer of their body cells.
Digestive and Circulatory System:
Their body has a central cavity known as gastrovascular cavity and the gastrovascular cavity opens at one end so both egestion and ingestion occurs through the only one opening and no special circulatory or nervous system occurs in coelenterata.
Reproduction in Coelenterata:
They mostly reproduce by the means of asexual reproduction, specially through the method of budding but they do not generally reproduce by formation of gametes but in some rare cases they show sexual reproduction.
Classification of Coelenterata:
Anthozoa:
Members of this class generally live in marine environments and medusa stage is not present and in their mesoglea fibrous connective tissue and migratory amoeboid cells present and common examples of this class is Xenia and Metridium.
Hydrozoa:
The most common examples of this class are Hydra and Obelia, in this class most members are mostly marine but a few members are observed in freshwater environments and in their life cycle polyp stage is most prominent and they generally live in colonial form.
Scyphozoa:
Aurelia is a very common example of class scyphozoa and their life cycle does not have any polyp stage but medusa stage is the dominant stage in their life cycle.
The umbrella-like shape is due to their medusa form and this medusa form produces a large number of gametes and the gametes take part in reproduction and tentacles like structure around their plates like body help them to swim in water bodies and help them to find their food easily.
Read More: Characteristics of Lower Invertebrates
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