PHYLUM PORIFERABy

Ms. Azra ArifD.A Degree College for woman

Phase VIII

INTRODUCTION Porifera means pore bearer

Early naturalist regarded the sponges as plants because of their frequent branching form and their lack of obvious movement.

The animal nature of sponges, first described in 1755, was confirmed in 1765 after observations of their water currents and the movement of their opening.

In structure, function, and development, sponges are distinct from other animals

Grouped as parazoa – multicellular animals with no well defined tissue

Approximately 5000-10,000 species has described which is found in all seas. Mostly are marine but only 150 species are found in the fresh water.

They are sessile, and asymmetrical Body organized around a system of water canals and chambers

SIZE ,STUCTURE AND COLOUR STRUCTUREVariable like bushy or tree like have finger like

projections.Some urn -shaped or shapeless, others shaped are vase

like ,tube like etc. SIZEVariable within species may vary with age ,

environmental conditions and food supply.0.4 inches -6.6 meters. ColourVariable Deep water sponge show neutral or brownish

colourShallow water sponge mostly are bright colour like red

orange and occasionally black, some are white.

SPONGE ANATOMY DIPLOBLASTIC MESENCHYME OSTIA OSCULUM SPONGOCOEL POROCYTES PINACOCYTES CHOANOCYTES SPICULES

Types of CellSponge cells are arranged in a gelatinous matrix called mesenchyme. Pinacocytes: These cells form the pinacoderm; they are flat epithelial-like cells. POROCYTES :Tube

like Open &close the pores

Choanocytes :cylindrical or conical cells one flagellum per choanocytes Lined internal cavity

Archaeocytes/amoebocyteTotipotent (transform into other type of cells)Important role in feeding &clear debris that block Ostiasclerocytes secrete spicules.Spongocytes secrete spongin.Collencytes collagen producing cells .Lophocytes secrete lots of collagen but may look like Collencytes.Grey cells act as sponge(immune system)Rhabidiferous cells secretes polysaccridesmyocytes that help regulate flow of water

.Types of SkeletonsDefinitiona skeleton is any fairly rigid structure of an animalSkeleton are of two typesEndo skeletonMesenchyme is function as endoskeletonMesenchyme is stiffened by mineral spicules , spongin fiber or bothSpicules made by silica and caco3Spicules have different shapeSimple rods ----three dimensional stars with up to six raysMay be separated , joint and fusedSpicules patterns are important

taxonomic features.

SKELETONExoskeleton Some sponges also secrete

exoskeletons that lie completely outside their organic components

For example sclerosponges ("hard sponges")

These exoskeletons are secreted by the pinacocytes that form the animals' skins

Exoskeleton is formed by caco3

WATER FLOW THROUGH THE SPONGE

WATER IN

WATER OUT

Osculum

Water current systemElements include in the water current system1)ostia; water enters (incurrent system)2)Choanocytes ( flagellated cells)3) Osculum (excurrent system )TYPES OF WATER CURRENT SYSTEMThree types of water current /canal system are found in the spongesMay be distinguished by arrangement of choanocytes and developmental of canal system.

There are three types of canal systems.

a. Asconoids: Flagellated

Spongocoels

WATER ENTERS OSTIASPONGOCOEL

OSCULUM OUT

All Calcarea are Asconoids: Leucosolenia and Clathrina are examples.

Syconoids

Flagellated Canal

They resemble Asconoids but are bigger with a thicker body wall.

WATER ENTERS

INCURRENTCANALS PROSOPYLES

RADIAL CANALS SPONGOCOEL

OSCULUM OUT. Classes Calcarea and Hexactinellida have species that are syconoid; the genus Sycon is an example.

Leuconoid TYPE Flagellated ChambersThese are most complex and are larger with many oscula.

WATERS ENTERS DERMAL OSTIA

SUBDERMAL SPACES BRANCHING

INCURRENT CANALS PROSOPYLES

FLAGELLATED CHAMBERS APPOPYLES

EXCURRENT CANALS LARGECHANNELS

OSCULUM OUT.

  Most sponges are leuconoid; it is seen in most Calcarea and in all other classes.

VITAL FUNCTIONSMovement

fundamentally sessile animals some species can move

across the bottom at speeds of 1–4 millimeters (0.039–0.16 in) per day

Movements of pinacocytes and other cells(amoeba like)

A few species can contract their whole bodies, and many can close their oscula and Ostia.

VITAL FUNCTIONS Feeding

Intracellular digestion Filters feeders Phagocytosis(pinacocytes,

Archaeocytes, choanocytes) Food particles not larger than

50um Carnivorous sponges Example family Cladorhizidae Extracellular digestion Feed on small crustacean Capture by spicules Completely lost their water flow

system and choanocytes

VITAL FUNCTIONS Excretory

By diffusion excrete out the nitrogenous waste (ammonia).

Respiratory diffusion by individual cells

CirculatoryChoanocytes create current, amoeboid cells transport food

NervousCell irritability shown by individual cells, can easilyrespond against somestimuli like contact chemicals and temp

Reproduction Reproduction are of two types1)Sexual reproduction2)Asexual reproduction Sexual Reproduction Most are monoecious with both male and

female sex cells in one individual Sperm arise from transformed

choanocytes. . In some Demospongiae and Calcarea,

oocytes develop from choanocytes; others derive them from archaeocytes

. Sponges provide nourishment to the zygote until it is released as a ciliated larva.

In some, when one sponge releases sperm, they enter the pores of another

Choanocytes phagocytize the sperm and transfer them to carrier cells that carry sperm through mesenchyme to oocytes.

Some release both sperm and oocytes into water.

Regeneration and Somatic Embryonogenesis.a) Sponges can regenerate wounded portions.

b. Sponge fragments aggregate into new structures, this is somatic embryogenesis.

Asexual Reproduction

a. External buds are small individuals that break off after attaining a certain size.ex. Scyphab. Internal buds or gemmules are formed by archaeocytes that collect in mesenchyme and are coated with tough spongin and spicules; they survive drought, freezing, etc.

IMMUNE SYSTEM

Sponges do not have complex immune system

Grey cells play important role Grey cells reject the grafting of

foreign material If the intrusions of cells persist

they secrete the toxic material that kills all the intruder cells of this area

This immune system is activated up to three weeks

Class Calcarea (Calcispongiae). These are calcareous sponges with spicules of calcium carbonate.. The spicules are straight or have three or four rays. Most are small sponges with tubular or vase shapes.. Asconoids, syconoid and Leuconoid forms all occur. Example Leucosolenia

Class Hexactinellida (Hyalospongiae)

. These are glass sponges with six-rayed spicules of silica.. Nearly all are deep-sea forms; most are radially symmetrical. Example hyalonema

Class Demospongiae. This class contains 95% of living sponge species.. Spicules are siliceous but not six rayed; they may be absent or bound together by spongin.. All are Leuconoid and all are marine except for Spongillidae, the freshwater sponges. Example euspongia

EVOLUTION AND PALEONTOLOGY

Evolution Porifera appeared in the early Cambrian period of

Paleozoic era. Three classes known in the middle of Cambrian

period(Hexactinellida/Hyalospongiae , Heteractinellida, Demospongiae)

Heteractinellida are extinct. Calcispongiae appeared in the carboniferous

periodPaleontology Based on their phylogenetic position , sponges are

oldest known animal fossil Late Cambrian period ( 1st fossil) 900 fossil have described

ECONOMIC IMPORTANCESponges have great economic importance and they are both beneficial

and harmful to mankind.Beneficial importance By dolphin By human Antibiotic compound EndosymbiontsHarmful importance Bore in calm, oysters and barnacles shells and completely destroy

them. Example Boring spongeBiochemical aspects Sponges feed on bacteria and other microorganism during the

selection of their food they produce substance with antibiotic activity(e.g.ectyonin)

Contain great variety of fatty substances e.g. sterols and cholesterol Spongin are formed by scleroprotein which is similar to keratin ,

found in other animals Accumulate silicon ,calcium and considerable amount of other metal