The document provides information about the phylum Porifera or sponges. It discusses that sponges are the simplest multicellular animals lacking tissues. They live in aquatic environments and have pores, canals and chambers for water circulation. Sponges have soft tissues and mineralized skeletons. They reproduce both sexually and asexually. The document classifies sponges into three classes based on their skeleton type and provides examples of representative sponges. It also describes the anatomy, morphology, life cycles, ecology and geological history of sponges.

1. Presentation
on
Phylum
Porifera

2. Presented
by:
Md. Ashraful
Islam
Md. Humayun
Kabir

3. WHAT IS PORIFERA
 Porifera, a phylum within the Kingdom
Animalia, is commonly refered to as sponges.
The sponge or poriferans, named from Latin
porus “pore” and ferre “to bear”, believed that
they are the simplest animals on the earth
because they have not true tissues such as
muscles, nerves, and internal organs. So
many scientists who study this animal
separated them from other Metazoans to
phylum of the Parazoa branch of Kingdom
Animalia.

4. Definition of Porifera
 The Porifera may be characterized
as a sedentary, aquatic, mostly
marine, solitary or colonial, radially
symmetrical or asymmetrical,
multicellular organisms; without
definite organ systems, mouth and
nervous tissue; with a pores, canals
and chambers through which a water
current flows.

5. Example of Porifera

6. Example of Porifera

7. General characterastics
# porifera are aquatic, mostly
marine animals.
# They are solitary or colonial.
# Body is radialy symmetrical or
asymmetrical and multicellular.
# Their body bears a lot of pores
which called ostia.

8. Continue......
# Body shape is cylindrical,
branching, vase like or globular.
# They have no definite organ
system like as mouth and
nervous tissue.
# Respiration occurs through the
osculam or oscula with the
current of water.

9. Continue......
# reproduction both asexual or
sexual. Asexual reproduction by
means formation of buds and
gemmules.
# Sexual reproduction by means of
ova and sperms.
# Fertilization is internal and
cleavage holoblastic.

10. Classification of Porifera
Porifera classify upto 3 classes on
the base of skeleton type
 1. Class Calcarea :
 Have a skeleton of separate
calcareous spicules(monoxon or
tetraxon)
 Solitary or colonial
 Body shape is base - like or
cylindrical
 Canal system asconoid, syconoid or
leuconoid

11. 2.Class Hexactinellida:
Called glass sponges
Body shape cylindrical or funnel
No epidermal epithelium
Choanocytes line finger shaped
Example: Hyalonama

12. 3. CLASS Demospongiae:
Larged sized, solitary or
colonial
Skeleton may be spongin fiber
Canal system leucon type
Example: Oscarella

13. Representative of Porifera
sycon
 Systematic position:
Phylam :porifera
Class :calcarea
Order :Heterocoela
Family :Sycettidae
Genus
:scypa(=sycon)

14. Some types of sponges:

15.  General characters:
 *Pore bearing ;asymmetrical or symmetrical.
 *Skeleton consist of calcareous spicules.
 *canal system syconoid type.
 Habits and habitats:
 Scypa formerly called sycon or grantia is widely
diatributed with numerous species. It is a small
marine sponge found permanently attached to
submerged rocks and other solid substratam,in
shallow waters near the coast,just below the low
tide mark.It is a branching,colonial sponge,though
solitary individuals are also found.

16. Canal system of sponges
 Three types of canal system of sponge:
 1. Asconoid:
 Simplest, radially symmetrical, vase like body.
 Body wall composed of an outer and inner epithelium
with a mesenchyme.
 Mesenchyme contains skeletal spicules.
 The wall is perforated by numerous microscopic
aperture which called ostia.
 Each pore is intracellular.
 Water current impelled by the flagella of the
choanocytes passes through the incurrent pores into
the spongocoel and out through the osculum

17. Flow chart…….
Water current from exterior
ln current pores spongocoel
 osculum water out.
Example:Leucosolenia

18.  2. Syconoid:
 First stage above the asconoid type. IT IS
FOREMED BY THE out pushing of the wall of an
asconoid sponge at regular interval into finger like
projection called radial canal. At first these radial
canals are free projection and the outside water
surround their whole length, for there are no
definite incurrent channel. But in most syconoid
sponge, the wall of the radial canal fuse in such a
manner as to leave between them tubular spaces,
the incurrent canals, which open to the exterior
between the blind outer ends of the radial canals
by apertures termed dermal ostia.

19. Continue….
 The water current in syconoid sponges takes
the following route:
 Dermal pores lncurrent canal
prosopyles radial canals lnternal
ostia
 spongocoel osculum out.
 Example: Scypha

20.  3. Leuconoid:
 The main characteristics of the leuconoid type of
canal system are the limitation of the choanocytes
to small chambers, the great development of the
mesenchyme, and the complexity of the incurrent
and excurrent canals. The course of water current
is dermal ostia lncurrent canals
prosodus(if present) prosopyles
flagellated chambers apopyles
aphodus(if present) excurrent canals
larger channels oscula out.
 Example: Oscarella

22. General Morphology
 The body of a simple sponge may be
compared to a vase, attached at the base,
open at the top, and with the wall perforated by
numerous canals opening externally as ostia.
The canals open into a central cavity, the
spongocoel, which itself opens through the
osculum at the top of the organism. Although
the sponges have very simple internal
structure that consist of soft parts and hard
parts (Skeleton).

24.  Soft parts
 Porocytes, Flat epidermal cells, and
Amoebocytes. The wall of a sponges have
two layaers of cells. The outer layer,
epidermis or The cellular part of the sponges
body consist of Choanocytes, ectodermis, is
composed of a single layer of thin, flat cells.
It’s seems to function chiefly as a protective
covering. The inner layer, or Flat epidermal
cells, lines the spongocoel and chambers and
parts or the whole of the canals in the wall. It is
consists of

25.  It is consists of Choanocytes or collar cells,
which have a collar surrounding the flagellum, are
both the food-gathering cells and the pumping
cells of the water circulatory system that operate
through central cavity (cloaca or spongocoel)
which opens at the top to the osculum .
Porocytes are tubular cells that make up
numerous tiny holes outer surface of the sponge
known as ostia or dermal pores. Amoebocytes
(live between the choanocytes and the epidermis)
carry out many of the sponge’s functions such as
transport of nutrients, secretion of the spicules,
and production of gametes.

26.  Hard parts – Skeleton
 Some sponges have not skeleton because
their body may be composed of a simple
colloidal jelly but most of sponges have
material consists of calcareous, siliceous, or
hard organic spicules. The skeleton is
secreted by spicules that can be grouped by
size, number of axes, and number of rays.

27.  Size: 1. Megascleres - large spicules 0.1 mm
to over 1.0 mm long. These may fuse to form a
coherent framework.

28.  2. Microscleres - small spicules 0.01 mm to 0.1
mm long. These are scattered all over the
body.
 Axes: 1. Monaxons - one axis

29.  2. Triaxons - three axes

30.  3. Tetraxons - four axes

31.  4. Polyaxons

32.  5. Desmas

33.  Rays: 1. Monactine - one ray 2. Diactine - two rays 3.
Triactine - three rays 4. Hexactine - six rays 5.
Polyactine - Multi-rayed (Lehmann, 1983
 Reproduction
 The reproduction of sponges exhibits many
characteristics of sessile or slow-moving animals.
Asexual reproduction is quite common, and occurs in
one of two ways:
 1.)Fragments that break off from the parent animal
may become new sponges
 OR,
 2.)Gemmules: collection of amoebocytes within a
hard, protective outer layer.

34.  Sexual reproduction
 in sponges is highly specialized. The simplest
and most primitive form of fertilization is external,
with the sperm and egg cells shed into the
water. However, in most sponges, fertilization
is internal. The sperm cells are carried by the
water currents out of the osculum of one sponge
and into the interior cavity of another
sponge. There they are captured and transferred
to ready eggs. Most sponges even provide a
certain amount of maternal care, retaining the
toung during the early stages of
development. The embryonic (not

35.  full grown, still developing) sponge develops into a
free-swimming larva that locates an appropriate
site, settles and attaches, and develops into an
adult sponge.
Most kinds of sponges
are hermaphrodites, meaning the same individual
has both male and female reproductive structures
and produces both sperm and egg cells. This is a
great advantage for animals with little or no
motilitty, as a hermaphrodite can mate with any
partner, with no limitations concerning gender.
 Sponges are very interesting and unique, with
many different and beautiful species. For a much
more detailed

36.  Ecology
 Sponges are ecologically variable and adaptable.
Sponges mostly living in marine which can be
found attached to surfaces anywhere from the
intertidal zone to as deep as 8,500 m. Some
species adapted to freshwater environment.
Modern calcisponges, demosponges, and
sclerosponges mostly occupy shallow water.
Calcisponges are usually found in water less than
100 meters, whereas sclerosponges can be found
to 200 meters. Hexactinellids are restricted to
deeper water (Rigby, 1987). Most sponges are
sessile so they feed by filtering out of the water
plankton and other suspended organic material
(Dodd, 1981).

37.  Geological distribution
 Sponges are worldwide in their distribution, and
range from waters of the polar regions to the
tropical regions. In the Paleozoic and Mesozoic,
shallow-water sponges were important reef
builders. Demosponges were vital frame builders
in reefs of North America, Europe and Australia
throughout the Ordovician, Silurian, Devonian,
Permian, and Triassic. Hexactinnelids were
important frame builders in Jurassic reefs of
Europe. Sclerosponges of the Paleozoic and
Mesozoic were also associated with reefs.
Calcisponges also contributed to Permian and
Triassic reef complexes of North America and
Europe (Rigby, 1987).

38.  Thank you so much for being with
us.
END