Phylum Porifera represents the simplest multicellular organisms in the animal kingdom. Commonly known as sponges, they are pore-bearing aquatic animals found in marine and freshwater environments. The term "Porifera" means "pore bearers," referring to their numerous tiny openings called Ostia that facilitate water flow.

Sponges are sessile (fixed in one place) and have a porous body that allows them to filter-feed on microscopic organisms. Despite their plant-like appearance, Poriferans are animals due to their cellular organisation, lack of chlorophyll, and ability to feed heterotrophically.

Characteristics of Phylum Porifera

Understanding the characteristics of Porifera (Class 11) is crucial for classifying and studying these creatures.

Body Organisation: Cellular level of organisation with loosely arranged cells.
Symmetry: Mostly asymmetrical, some exhibit radial symmetry.
Habitat: Primarily marine, a few species occur in freshwater.
Skeletal Structure: Supported by spicules (calcareous/siliceous) or spongin fibres.
Feeding Mechanism: Filter feeders that exhibit holozoic nutrition.
Respiration & Excretion: Occurs via diffusion.
Reproduction: Asexual (budding, fragmentation) and sexual (internal fertilisation).
Regeneration: High regenerative ability to replace lost body parts.
Nervous System: Lacks a nervous system but possesses neurosensory cells.
Circulatory System: No distinct circulatory system; transport of nutrients occurs via amoebocytes.

Classification of Phylum Porifera with Examples

Phylum Porifera is classified into three major classes based on skeletal composition:

1. Class Calcarea (Calcareous Sponges)

Found in shallow marine waters.
Skeleton made of calcium carbonate (CaCO₃) spicules.
Body structure varies: Asconoid, Syconoid, or Leuconoid.
Examples: Clathrina, Scypha.

2. Class Hexactinellida (Glass Sponges)

Found in deep-sea environments.
The skeleton consists of six-rayed siliceous spicules.
Radial symmetry, cylindrical body shape.
Examples: Euplectella (Venus Flower Basket), Hyalonema.

3. Class Demospongiae (Common Sponges)

Found in both marine and freshwater.
The skeleton consists of spongin fibres and siliceous spicules.
Asymmetrical and leuconoid canal system.
Examples: Spongia, Spongilla (Freshwater Sponge).

20 Examples of Porifera with Names

Here are 20 notable examples of Porifera:

Sycon – A colonial marine sponge.
Spongilla – A freshwater sponge.
Cliona – A boring sponge found in corals.
Euplectella – Venus flower basket.
Hyalonema – Glass rope sponge.
Leucosolenia – Small, tubular marine sponge.
Oscarella – Encrusting sponge found in reefs.
Tethya – A spherical sponge.
Callyspongia – Common bath sponge.
Haliclona – Marine sponge with a soft texture.
Mycale – Reef-associated sponge.
Hippospongia – Used for commercial sponges.
Ircinia – Large, bushy sponge.
Axinella – Tree-shaped sponge.
Chondrosia – Smooth, soft sponge.
Petrosia – Found in tropical marine regions.
Stelletta – Thick-walled sponge.
Geodia – Forms massive colonies.
Cinachyra – Deep-sea sponge.
Dysidea – Encrusting and branching sponge.

Unique Features of Porifera

To make Vedantu’s content more unique and valuable, here are additional insights:

Bioactive Compounds: Some sponges produce antimicrobial and anti-cancer compounds.
Symbiotic Relationships: Many sponges host symbiotic algae, bacteria, or other marine organisms.
Role in Ecosystem: Sponges contribute to nutrient cycling and maintain marine biodiversity.
Historical Significance: Fossil records suggest sponges existed over 600 million years ago, making them among the oldest animal groups.

Porifera: Importance and Applications

Ecological Role: Sponges act as natural water filters, improving water quality.
Biodiversity Hotspots: Provide shelter to marine organisms.
Pharmaceutical Uses: Sponges are a source of bioactive compounds used in medicine.
Commercial Uses: Spongia sponges are used in the bathing and cleaning industries.

Conclusion

Phylum Porifera is a group of simple yet vital animals. Their unique filtration system, skeletal diversity, and biological significance make them an essential part of the marine ecosystem. Understanding Porifera: characteristics and examples help students and researchers appreciate their evolutionary importance.

FAQs on Phylum Porifera: Characteristics, Classification and 20 Examples

1. What are the main characteristics of phylum Porifera?

Poriferans are pore-bearing animals with a cellular level of organisation. They lack true tissues and organs, rely on filter-feeding, and exhibit asexual and sexual reproduction.

2. Give 10 examples of Porifera.

Some Porifera examples with names include:

Sycon
Spongilla
Euplectella
Cliona
Hyalonema
Oscarella
Leucosolenia
Hippospongia
Axinella
Dysidea

3. What is the classification of Porifera based on?

Porifera is classified into Calcarea, Hexactinellida, and Demospongiae based on their skeleton composition.

4. Why were Poriferans initially mistaken for plants?

Due to their sessile nature and symbiosis with algae, early biologists misclassified sponges as plants. Later, their feeding mechanism and cellular organisation confirmed their status as animals.

5. How do Poriferans reproduce?

Poriferans reproduce asexually (budding, fragmentation) and sexually (internal fertilisation, larval development).