Ctenophore: Definition, Classification, Types, Characteristics, Adaptations

Ctenophora is a simple, soft-bodied phylum of marine animals also known as sea walnuts or comb jellies. They are known for their beautiful, glass-like bodies that usually emit light at night due to their bioluminescence. Ctenophores propel themselves in water with eight rows of tiny hair-like appendages called ctenes or comb plates. To date, researchers have found about 100 species of ctenophores, and all of them live in salty oceans and seas.

This Story also Contains

1. Definition Of Ctenophora
2. Taxonomy And Classification of Ctenophora
3. Morphology And Anatomy of Ctenophora
4. Physiology and Behaviour of Ctenophores
5. Habitat And Distribution Of Ctenophora
6. Ecological Role Of Ctenophora
7. Recommended Video on Ctenophores

These animals have a two-layered body (diploblastic) and display radial symmetry, i.e., they have body parts disposed on a central axis. They do not have stinging cells but use sticky cells called colloblasts to catch food. Ctenophores are usually small, but some of them reach a length of 1.5 meters. They are an important part of the marine food web as predators and prey.

Definition Of Ctenophora

Ctenophora is a class of marine animals that are small, soft, and jelly-like in structure. They are also known as comb jellies due to the eight rows of comb-like plates (ctenes) that they possess, which help them move through water. Ctenophores are diploblastic, i.e., their bodies consist of two layers of cells, and they exhibit radial symmetry. They exist only in saltwater and are characterised by their glowing bioluminescence.

• Ctenophores have specific adhesive cells named colloblasts to trap prey.
• Their body are clear and tend to glow in the dark.
• They swim with the help of rows of minute cilia on comb plates.
• Ctenophores lack stinging cells such as those in jellyfish.
• They serve a key function in the ocean ecosystem as predators of small animals.

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Taxonomy And Classification of Ctenophora

Ctenophora is a minor phylum of marine invertebrates, which are divided into groups according to the shape of their bodies, tentacle type, and absence or presence of features. They are the kingdom Animalia and split from cnidarians because they do not have stinging cells. Scientists have placed ctenophores into various classes and orders based on how they appear and move in water. Its purpose of explore is their diversity and function in the marine system.

• Ctenophora is a phylum called Ctenophora within the kingdom Animalia.
• They are further divided into two classes: Tentaculata and Nuda.
• Class Tentaculata comprises species with tentacles.
• Class Nuda comprises species without tentacles.
• All ctenophores are marine and live in saltwater.
• They are diploblastic animals and exhibit radial or biradial symmetry.
• Ctenophores are classified under a distinct phylum because of their cilia and distinct body structure.
• There are approximately 100 species of ctenophores discovered to date.

Morphology And Anatomy of Ctenophora

Ctenophora are jelly-like, soft, and marine animals whose bodies are transparent and can be oval, spherical, or ribbon-shaped. Their body has bilateral symmetry and consists of two layers (diploblastic) with a jelly-like mesoglea between them. They have eight rows of comb plates with cilia lining them that assist in swimming. They have two long tentacles carrying colloblasts for food capture by most species. Within, they have a basic digestive tube, a nerve net, and no skeleton or hard structures. All basics about the Morphology and Anatomy of Ctenophora are discussed below:

Physiology and Behaviour of Ctenophores

Ctenophores have a simple physiology appropriate to their life in oceanic waters. They glide effortlessly with the help of comb plates beating and capture food with colloblasts on their tentacles. Their body has bioluminescence, which helps them glow when it is dark. They have a simple nerve net for movement and touch response. Ctenophores are free-swimming predators which drift or glide while feeding on small animals such as plankton. Other important features are discussed below in the table:

Habitat And Distribution Of Ctenophora

Ctenophora inhabit of marine environments alone, existing in seas and oceans all over the world. They float freely close to the water surface most of the time, although species exist at deeper levels. Ctenophora exist in saltwater only, not found in freshwater. Ctenophores exist globally across tropical, temperate, as well as polar regions, indicating their capacity to adapt in various temperatures and climates. Some important points are discussed below:

• Ctenophores are found in oceans worldwide, inhabiting almost all major marine environments from coastal waters to the open ocean, and pelagic to deep-sea settings.

• Their geographic distribution somewhat mirrors that of the sea, existing in polar and tropical waters and varied depth zones, such as surface and deep-sea environments.

• In these different marine environments, its presence explains its adaptability and ecological importance in global oceanic ecosystems.

Ecological Role Of Ctenophora

Ctenophora are key components of the marine ecosystem as active predators of plankton and small crustaceans. Feeding on these creatures, they control plankton populations and preserve the balance of the food chain. They are also prey for larger aquatic animals such as fish and turtles. In some areas, when their population grows very fast, ctenophores can influence fisheries by competing with juvenile fish for food. Some other important points are discussed below:

• Ctenophores form an integral part of the marine food chain by preying on small marine animals like zooplankton, copepods, and even the larvae of fish, thereby controlling their populations.

• They capture their prey with help from the colloblasts on their tentacles. In turn, they also become the prey for larger marine animals like fish and jellyfish.

• Ctenophores are known to affect the population dynamics of marine species by preying on zooplankton and fish larvae.

• This impact, as with other invasive species like Mnemiopsis leidyi, could result in the disruption of ecosystems like the Black Sea, causing a decline in local populations and fundamental changes in food web structures.

• This need not be so if the population of ctenophores is monitored and managed to protect marine biodiversity.

Recommended Video on Ctenophores

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