Phylum Ctenophora

Introduction

The phylum family comprises the variable species with different habitats. Many of them follow the ground-level living style, and some depend on their host to reach their adult stage. A wide range in this family finds their special livelihood in marine life. The species of the phylum may depend either on freshwater or salty seawater. Water life is a very safe option for these types of organisms. These organisms form a jelly shape with eight external vertical ciliated comb plates. This is why their mention is in comb jellies in studies.

Definition

These are the simple animals that live only in marine water. They like to build their habitats near the shore of the deep ocean, inshore, or offshore from polar to tropical nature. They are organisms with a soft tissue structure with a jelly-like feel. Their appearance is generally planktonic and without any pigments. They have a translucent and comb-like structure which mentions them as the comb jellies.

Diversification

As per the survey, there are 100-150 species of Phylum Ctenophora on earth. Their planktonic biomass and translucent appearance make them a significant mention in the group of phylum families. These are the most diverse creatures.

Habitat nature

The comb jellies generally follow the marine habitat because of their body shape and ability to absorb the atmospheric variations. They are present under 2000 to 3000 meters down the water surface. The water body can deal with the possible variables such as oceans to the open water bodies. Sometimes there is variation in the temperature of the water bodies. However, the Ctenophores act so that they easily adapt to the change.

Geographical appearance

Earth has a 75% cover of water bodies; hence these species of Ctenophora have a wide range to form their habitat. These species have a global presence from the Arctic Sea to the Black sea.

Lifespan

Their lifespan mostly depends on the atmosphere in which they are surviving. On average, according to the phylum Ctenophora characteristics, the life span is either less than a month or more than three years.

Physical appearance

As these species have the highest range of species in this family, there are many body formation, characteristics, and appearance variations. In the Phylum Ctenophora, These varieties vary from small to big shapes and from round to long formations. Some of them are symmetrical to flat surfaces, while others have a long ribbon shape appearance. The length of this creature reaches the maximum value of 2 meters. The physical appearance is the translucent jelly shape; the soft tissue-like look makes them attractive. They have eight external vertical ciliated comb plates that help in locomotion. Some of its members show the phenomenon of bioluminescence.

 Structure

They have tissue level organisation and are diploblastic and acoelomate.

Nutrition

Digestion is extracellular as well as intracellular. They are carnivorous.

Nervous System

It is of diffused type. The brain and central nervous system are absent.

The respiratory excretory and circulatory system is absent.

Reproduction

Most of them have male and female organs present in a single body. Hence internal fertilisation is the most common way of reproduction. Species undergo reproduction by a sexual method. Fertilisation is external with indirect development.

Classification

There are more than 100 species and their types, which form a group in two distinct Classes. The classification takes place based on the presence or absence of tentacles. The two classes are Class Tentaculata and Class Nuda. 

• Tentaculata

They are entirely adults who consist of two long tentacles. The best thing is that their mouth surface has a narrow opening and a very small pharynx. Some of the larvae may have the tentacle. 

This class is further divided into five orders.

• Cydippida

Their tentacles are long and have branches with their round or oval bodies. They consist of a simple body with a digestive canal that ends blindly. They have no anal pores. Tentacles retract into pouches. Examples: Hormiphora, Mertensia

• Lobata

They consist of a laterally compressed body with two large oral lobes. Larva consists of sheath tentacles, while the sheath is absent in adults. The oral ends are connected with the gastro canal by the ring. Example: Bolinopsis, Mnemiopsis

• Cestida

They have a flat ribbon-like body with a sheath containing tentacles. However, there is a remarkable reduction in tentacles in this order of the phylum Ctenophora. Their comb plates have four consecutive rows. Example: Cestum

• Platyctenida

Two tentacles are present in this order of phylum Ctenophora in the sheath. Here only adults have the comb plates, but those are reduced. Example: Ceoloplana, Ctenoplana.

• Thalassocalycida

These Ctenophores have transparent and colourless bodies that may be 15 cm. They have a small pair of tentacles hanging by their peduncles. Example: Thalassocalycle inconstans.

• Ganesha

These Ctenophores have a pair of tentacles and a pair of small oral lobes.

• Cryptolobiferida

• Cambodia

• Class 2: Nuda

This phylum class Ctenophora has a large conical body shape with a wide mouth and large stomach. Here the body of the species undergoes a compression around the lateral side. There is a single class under this group:

• Berioda:

They have a largemouth. This order of the phylum Ctenophora is without tentacles and oral lobes. The mouth is wide, and the stomach is also significant. Example: Beroe

Conclusion

Marine life is full of surprises, and the species there define the wonder of nature beautifully. The phylum Ctenophora species survive in water by the presence of certain features.. The complete phylum makes its appearance in many forms in terms of body formations, appearance, and characteristics. Over 100 species and still undergoing the evolution stage make these wonderful creatures on earth. Marine species of this kind are present around all over the world under all atmospheric conditions. They are divided into two classes, namely Tentaculata and Nuda.