Phylum Porifera

Phylum Porifera, also known as sponges, is a group of simple aquatic animals that lack true tissues and organs. Porifera phylum animals are the lowest multicellular animals belonging to the animal kingdom. Porifera word is taken from Latin which means pore-bearing species. Around 5000 species are included in the phylum Porifera. Porifera animals have pores which are known as Ostia. These are the first organism Pore-bearing multicellular animals.

Poriferans are spongy in appearance that’s why they are known as sponges. Porifera is attached to the substratum. They get their food via absorption. Firstly due to their green appearance, they are included in the plant kingdom but later on, due to their symbiotic association with algae and life cycle, they are included in the animal kingdom.

Characteristics of Phylum Porifera

The following are some characteristics of phylum Porifera:

• They are present mostly in marine water but also present in freshwater.
• Their bodies are uneven and loosely arranged.
• Porifereans can either be symmetrical or asymmetrical.
• No organs are present inside the body.
• They are cylindrical.
• They have a cellular level of organization.
• Sponginin fibers are secreted by spongioblast and spicules by scleroblast.
• Porifera reproduces asexually via fragmentation or budding.
• Numerous pores are present over the body which is known as Ostia.
• The cavity present inside the body is known as spongocoel which is open to the surrounding via osculum.
• They take food via a Holozoic mode of nutrition.
• Porifera animals do regenration.
• Indirect development and holoblastic cleavage.
• Respiration and excretion did via diffusion.

Classification of Phylum Porifera

Every one of the types of this phylum is assembled into three classes, depending mostly upon the idea of the skeleton. They are both marine and freshwater animals. 

Calcarea

• They all are present in both marine and freshwater.
• Their skeleton comprises calcareous spicules which are forms of calcium carbonate.
• The body is cylindrical
• They show radial symmetry.
• Body organization of calcera are asconoid, leuconoid and syconoid.
• Examples: Clathrina, Leucosolenia, Scypha

Hexactanellida

• They are present in marine and also in the deep sea.
• Their skeleton shows six-rayed siliceous spicules.
• The canal system is sycon and leucon type
• The body is cylindrical and has radial symmetry.
• Example: Euplectella, Hyalonema

Demospongiae 

• Present in both freshwater and marine water.
• Leuconoid type canal system is present
• The skeleton system comprises spongin fibers and siliceous spicules. 
• They are asymmetrical
• The cylindrical body is present.
• Example: Cliona, Spongia, Spongilla, Chalina

Porifera Examples

Some the example of the Phylum Porifera are:

Sycon

These are marine sponges present either solitary or colonial which are attached to rocks. Cylindrical shape and have numerous spores. The flagellated cell is made from a radial canal. From the Ostia, water enters the body and reached radial canals via prosopyles. Sycon reproduces both sexually and asexually.

Hylonema

These are also called glass rope wipes present in marine water. It is round or oval with twisted tufts. 

Cliona

They are also called Boring Sponges, found in coral skeletons, mollusk shells, and other calcareous articles. They are green, purple, or light yellow in variety. The canal system is one of the main characteristics of leuconoid sponge. They reproduce both sexually and asexually.

Euplectella

These are also called Venus flower baskets present in marine water. These are long cylindrical and curved present on the mud of the upper surface of the sea. Simple synconoid canal systems are present. Their skeleton consists of silicious spicules which are fused around their tips and form a 3-D structure.

Spongilla

They are majorly found in ponds, lakes, streams. The body is covered via the thin dermis, and small pores i.e., Ostia are present on the surface. Rhagon-type canal systems are present in Spongilla. They reproduce via both modes. 

FAQs on Phylum Porifera

Q1: Where are the Choanocytes in Sponges present?

Answer:

Cells called Choanocytes or collar cells are available, coating the spongocoel and channels. With their flagella distending out.

Q2: What are the 5 characteristics of Porifera?

Answer:

• Phylum Porifera organisms don’t have organs.
• They are pore-bearing animals
• They show the Holozoic mode of nutrition.
• They do regeneration if any part is lost
• THey have radial symmetry bodies.

Q3: What are the 3 types of sponges?

Answer:

There are 3 types of sponges those are:

1. Asconoid
2. Syconoid
3. Leuconoid

Q4: What do sponges eat?

Answer:

These mostly eat detritus, plankton, bacteria, and viruses. They also feed over dissolved nutrients.

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