Comprehensive Study Notes on Kingdom Porifera
SET 1 – GENERAL AND INDIRECT QUESTIONS ON PORIFERA
1. What are the general characteristics of sponges?
Sponges are multicellular, aquatic (mostly marine), sessile, and filter-feeding animals.
They have numerous pores (ostia), lack true tissues and organs, and show a cellular level
of organization. Reproduction occurs both sexually and asexually.
2. Why are sponges considered the simplest multicellular animals?
They possess specialized cells but no true tissues or organs, show intracellular digestion,
and depend on water flow for all life processes.
3. How do sponges obtain food?
Sponges feed by filtering microscopic food particles from water drawn through ostia and
trapped by collar cells (choanocytes).
4. How does water circulation benefit sponges?
It provides food, oxygen, removes wastes, and assists in reproduction by carrying
gametes and larvae.
5. What are choanocytes and their roles?
They are flagellated collar cells that create water currents, capture food, and can develop
into sperm cells during reproduction.
6. What is the body organization level of sponges?
Cellular level — different cells perform specialized functions but are not organized into
tissues.
SET 2 – CLASSIFICATION, CANAL SYSTEMS, AND
REPRODUCTION
7. How are sponges classified?
Based on the type and composition of their skeletal material: Class Calcarea (calcium
carbonate spicules), Hexactinellida (silica spicules), and Demospongiae (spongin fibers or
silica spicules).
8. Describe the canal system in sponges.
It consists of ostia, incurrent canals, flagellated chambers, and osculum. Water flow
enables feeding, respiration, and waste removal.
9. Types of canal systems?
Asconoid (simplest), Syconoid (moderate), and Leuconoid (most complex). Evolutionary
trend: Asconoid → Syconoid → Leuconoid.
SET 1 – GENERAL AND INDIRECT QUESTIONS ON PORIFERA
1. What are the general characteristics of sponges?
Sponges are multicellular, aquatic (mostly marine), sessile, and filter-feeding animals.
They have numerous pores (ostia), lack true tissues and organs, and show a cellular level
of organization. Reproduction occurs both sexually and asexually.
2. Why are sponges considered the simplest multicellular animals?
They possess specialized cells but no true tissues or organs, show intracellular digestion,
and depend on water flow for all life processes.
3. How do sponges obtain food?
Sponges feed by filtering microscopic food particles from water drawn through ostia and
trapped by collar cells (choanocytes).
4. How does water circulation benefit sponges?
It provides food, oxygen, removes wastes, and assists in reproduction by carrying
gametes and larvae.
5. What are choanocytes and their roles?
They are flagellated collar cells that create water currents, capture food, and can develop
into sperm cells during reproduction.
6. What is the body organization level of sponges?
Cellular level — different cells perform specialized functions but are not organized into
tissues.
SET 2 – CLASSIFICATION, CANAL SYSTEMS, AND
REPRODUCTION
7. How are sponges classified?
Based on the type and composition of their skeletal material: Class Calcarea (calcium
carbonate spicules), Hexactinellida (silica spicules), and Demospongiae (spongin fibers or
silica spicules).
8. Describe the canal system in sponges.
It consists of ostia, incurrent canals, flagellated chambers, and osculum. Water flow
enables feeding, respiration, and waste removal.
9. Types of canal systems?
Asconoid (simplest), Syconoid (moderate), and Leuconoid (most complex). Evolutionary
trend: Asconoid → Syconoid → Leuconoid.
