Biology of Sponges

1. PHYLUM PORIFERA
Prepared by:
JOHN FLORENTINO E. ECHON
G15 0099

2. CHARACTERISTICS
• Freshwater and marine
• Simplest of all animals
• Hermaphrodites
• Asymmetrical
• No systems for repro, digestion,
respiration, sensory, excretion

3. CHARACTERISTICS
• No true tissues or body systems of
any type
• Almost all species are sessile
suspension feeders, larvae free-
swimming
• Multicellular
• Totipotent cells: like stem cells!

4. BODY STRUCTURE
Spicules
composed of calcium
carbonate or silicon
dioxide
Often used in sponge ID

6. Cells that line surfaces
 Amoebocytes
(archaeocyte)
 amoeba-like cells
 store, digest and
transport food,
excrete wastes,
secrete skeleton
 give rise to buds in
asexual
reproductionS
sclerocytes - secrete spicules
spongocytes - secrete spongin
collencyotes - secrete collagen

7. Cells that line surfaces
Mesenchyme
 Beneath the
pinacocytes - a
gelatinous protein layer
 it contains the skeletal
material (ie. spongin
and spicules) and
amoebocytes

8. Cells that line surfaces
Pinacocytes
outer cells covering
sponge; equivalent of
epiderm

9. Cells that line surfaces
 Choanocytes-
 similar to
choanoflagellates
 collared cells with
flagella - create
water current and
collect food matter

10. Cells that line surfaces
Porocytes
 Form ostia
 Cylindrical tube-like
cells
 Contractile - open
and close pore to
regulate diameter

11. Sponge Anatomy
Pechenik, 1996
Pinacocyte
Choanocyte
Amoebocyte
Porocyte

12. BODY STRUCTURE

13. Body structure/aquiferous system
 Structural conditions of sponges:
 Trend from one large chamber
to numerous small chambers.
 Ascon: one main chamber
(spongocoel) lined with
choanocytes
 Sycon: choanocyte chambers
off the spongocoel
 Leucon: has multiple layers of
choanocyte chambers

14. Syconoid sponges
 Syconoid: choanoderm folded
 Mesohyl two layers thick:
Outer region is cortex (contains
skeletal material)

15. Asconoid sponges
 Asconoid: one-cell thick choanoderm is
simple and continuous
 ~10 cm height
 Thin walls enclose central cavity; atrium
opens outside via osculum
 Pinacoderm has specialized cells;
porocytes
 External opening of porocyte canal is
ostium or incurrent pore

16. Leuconoid Sponge
 Leuconoid: choanoderm
subdivided into separate
flagellated chambers

17. Types of Spicules
4 general types
 Monaxon- needle-like or rod-like; straight or
curved
 Tetraxon- has 4 prongs
 Triaxon or Hexaxon- 3 or 6 rayed
 Polyaxon- multiple short rods radiating from a
common center; burr shaped, star shaped or
like a child's jack.
 Some species have a mixture of types

18. TAXANOMY
• Taxonomy based on skeletal
elements
• Now embryological, biochemical,
histological, and cytological
methods to diagnose sponge taxa

19. Three classes
1. Class Calcarea
2. Class Demospongiae
3. Class Hexactinellida

20. Class Calcarea: Calcareous sponges
Found in Shallow, tropical water, near shore
Leucetta
Clathrina
Spicules =
calcium
carbonate
Calcarean
spicules lack
hollow canals =
strong

21. Leucettusa lancifera Dendy, 1924
Class Calcarea: Calcareous sponges

22. Class Hexactinellida (Glass sponges)
 Silica spicules
 Spicules join at right angles, sponge appears artificial
Symplectella rowi Dendy, 1924

23. Class - Hexactinellida
Euplectella

24. Class Demospongiae (Demosponges)
 Largest and most diverse class of sponges, ~ 90
percent of sponges
 Spicules either spongin, an organic substance; or
silica, a mineralized substance
Oscarella

25. Class Demospongiae
 Genera Adocia, Halisarca, Myxilla

26. Class Demospongiae
Aciculites pulchra Dendy, 1924
18

27. Class Demospongiae
Stelletta crater Dendy, 1924

28. Spongilla

29. Aquiferous system
 Brings water to cells
 1 x 10 cm sponge pumps 22.5
l water daily
 Large sponge filters body
mass every 10-20 s

30. Nutrition
 Carnivorous sponges: Family
Cladorhyzidae!
 Stalked; tentacle-like extensions
covered with hook-like spicules
capture prey
 Individual cells engulf and digest
prey (intracellular)
 Symbionts provide nutrients to
some sponges
 Methanotrophic bacteria (in some
carnivorous sponges!)
 Photosynthetic protists Photo: Michel Phlibert

31. Nutrition, Excretion, and Gas Exchange
 Intracellular digestion
 Continuously circulate water
 Size selective feeders
 Food capture
 Phagocytosis and pinocytosis

32. Excretion
 Ammonia and gas
exchange
 Diffusion

33. Most species are sessile as adults
 Cells frequently move and rearrange themselves
 Amoebocytes are highly mobile
 One species, Tethya seychellensis, Red Sea, has sticky,
filamentous extensions
 Filaments contract and pull sponge along.
Movement

34. Sexual Reproduction in
Sponges
 gametes formed by amoebocytes
 there are both hermaphroditic and dioecious species
 most hermaphroditic species produce eggs and sperm
at different times so they do not self fertilize
 sperm is released into environment via osculum and is
brought in by another sponge via ostia
 fertilization takes place in parent sponge
 zygote is expelled - it drops to bottom and begins to
develop

35. Reproduction and Development
 Sexual process (Demospongiae and Calcarea)
 Sperm and oocytes released into environment via aquiferous
system
 Sperm release -”smoking sponges”
 Fertilization in open water (oviparous)
 Few viviparous: sperm into nearby sponge’s aquiferous
system; sperm to oocyte for fertilization

36. Reproduction and Development
Madsen sponge releasing
sperm

37. Asexual Reproduction in Sponges
 two types:
 Budding- fragmentation of body wall, buds appear as outgrowth on sides of
sponge
when they reach a certain size they drop off and settle to bottom to
form a new sponge
 Gemmules- occurs only in freshwater sponges
gemmules are groups of food laden amoebocytes that deposit a hard
covering of spicules around them
formation is triggered by environmental conditions such as decreased
temperatures
they allow the sponge to pass the winter or periods of drought
after which the outer covering breaks open and a new sponge
develops

39. Ecology and Importance
Class calcarea: Found primarily shallow water and tropical
Class hexatenilleda: Marine, primarily deep water
 Ideal habitats for marine animals such as snails,
sea stars, sea cucumbers, and shrimp
 Mutually beneficial relationships with bacteria,
algae and plant-like protists
 Many are green due to these organisms living in
their tissues

40.  Deep-water sponges provide important habitat to many
species of fish and invertebrates, mostly as a source of
refuge from predation and adverse conditions (e.g.,
strong currents) and as focal sites for foraging on prey
species that aggregate in sponge habitat.
 others likely use sponge habitat as breeding sites.

41. RELATED RESEARCH:
sponges produce a wide variety of bioactive compounds
which are widely used in pharmaceuticals: antibiotics,
asthma, arthritis,
anticancer drugs, chemicals that promote
wound healing, anti-inflammatories
eg. antibiotics against bacteria such as E. coli and Staph
aureus
eg. Acyclovir from Caribbean sponge
1st antiviral compound approved for human use
fights herpes infections used since 1982

42. RELATED RESEARCH:
Sponges use chemicals to prevent other
sponges from growing near them. These
chemicals can prevent cancer cells from
growing.
One of the first drugs for treating cancer
Tectitethya keyensis at Bocas del Toro cancer,
cytosine
arabinoside, was isolated from the sponge
Tectitethya crypta.

43. Marine sponge collagen: isolation,
characterization and effects on the
skin parameters surface-pH,
moisture and sebum
Isolation, characterization and
molecular weight determination
of collagen from marine sponge
Spirastrella inconstans (Dendy)