Sponge Classification and Characteristics

Study Notes

Sponge Classification

Domain: Eukarya
Kingdom: Animalia
Phylum: Porifera, meaning "pore bearing"

Sponge Characteristics

Exhibit asymmetry
Function as filter feeders
Lack true tissues
Possess an internal skeleton made of spicules or collagen fibers

Sponge Body Types

Ascon Sponge: Least complex structure
Sycon Sponge: Intermediate complexity
Leucon Sponge: Most complex, efficient in extracting oxygen and food particles

Calcarea Class

Comprises marine sponges
Characterized by small, needle-shaped spicules made of calcium carbonate with 3-4 rays
Can exhibit ascon, sycon, or leucon body types

Demospongiae Class

Commonly known as bath sponges or commercial sponges
Features beautifully colored marine sponges with skeletons made of spongin

Hexactinellida Class

Comprises marine sponges with six-rayed spicules made of silica
Can display sycon or leucon body types
Some taxa inhabit freshwater environments like streams, ponds, and lakes

Spicules

Structural components that provide support and deter predators; can be made from calcium carbonate or silica

Sponge Structure - Pinacocyte

Flattened cells that form the outer body wall of the sponge

Sponge Structure - Amoebocyte

Mobile cells capable of transforming into various cell types, responsible for transporting food within the sponge

Sponge Structure - Porocyte

Doughnut-shaped cells that facilitate water flow into the radial canals

Sponge Structure - Choanocyte

Also known as collar cells, they line the radial canals, using flagella to capture food particles, aiding in the sponge's filter-feeding process

Water Flow Through the Sponge

Water enters through ostia (pores)
Moves through incurrent canals via porocytes
Flows into radial canals lined with choanocytes
Enters the spongocoel (the central chamber)
Exits through the osculum

Importance of Water Transport in Sponges

Essential for respiration, nutrient transport, digestion, and excretion
Allows exchange of oxygen, nutrients, and waste via diffusion and water currents

Asexual Reproduction

Two main types: fragmentation and budding

Fragmentation

Sponges break into parts capable of regenerating into new individuals

Bud Formation

External buds: small sponges detach from the parent
Internal buds, or gemmules: balls of amoebocytes encased in spongin and spicules that survive harsh conditions

Sexual Reproduction

Occurs when conditions are favorable
Choanocytes transform into haploid sperm via meiosis and are released into the water
Sperm enter a different sponge, fuse with a haploid egg, and develop into ciliated larvae that settle and mature into new sponges

Asexual Reproduction: Gemmule Diagram

Represents the structural components associated with gemmule formation and resilience

Description

Explore the fascinating world of sponges with this quiz focused on their classification, characteristics, and body types. From the simplest Ascon to the complex Leucon, learn how these unique creatures filter feed and their structural adaptations. Perfect for biology enthusiasts and students alike!