Download - Phylum Porifera
PHYLUM PORIFERABy
Ms. Azra Arif
D.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
colour
Shallow 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/amoebocyte
Totipotent (transform into other type of cells)
Important role in feeding &clear debris that block Ostia
sclerocytes 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 polysaccrides
myocytes that help regulate flow of water
.Types of SkeletonsDefinitiona skeleton is any fairly rigid structure of an animal
Skeleton 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 fused
Spicules patterns are important taxonomic features.
SKELETON
Exoskeleton 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 system
Elements include in the water current system
1)ostia; water enters (incurrent system)
2)Choanocytes ( flagellated cells)
3) Osculum (excurrent system )
TYPES OF WATER CURRENT SYSTEM
Three types of water current /canal system are found in the sponges
May 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 Chambers
These 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 Nervous
Cell irritability shown by individual cells, can easilyrespond against somestimuli like contact chemicals
and temp
Reproduction
Reproduction are of two types
1)Sexual reproduction
2)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. Scypha
b. 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
period
Paleontology 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 Endosymbionts
Harmful importance Bore in calm, oysters and barnacles shells and completely destroy
them. Example Boring sponge
Biochemical 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