Phylum Porifera

1. Phylum Porifera

2. Introduction

3. Sponges • Filter-feeding system • many tiny pores and canals; adequate for their inactive life habit • Sessile animals • depend on water currents to bring them food and oxygen and carry away their body wastes • No organs or true tissues • Bodies are little more than masses of cells embedded in a gelatinous matrix • stiffened by a skeleton of minute spicules • calcium carbonate or silica and collagen

5. Sponges • Vary in size • few millimeters to more than 2 meters • Brightly colored • (red, yellow, orange, green, and purple) • Some are radially symmetrical, but many are quite irregular in shape • Some stand erect, some are branched or lobed, and others are low in form (encrusted)

6. Erect

7. Branched or lobed

8. Encrusted

9. Ecological Relationship • More than 5000 species of sponges are marine • 150 species live in fresh water • Found in all seas and at all depths • A few are found in brackish water • Embryos are free swimming • Adults attach to objects (rocks, corral, shells, etc.)

10. Ecological Relationship • The calmer the water, the taller and straighter the sponge grows • Larger sponges tend to harbor a large variety of invertebrates commensally • (one species benefits and the other is not harmed) • Elaborate skeletal framework and often noxious odor provide protection against predators

11. Sea Turtle Eating a Sponge

12. Form and Function • Ostia – many tiny pores for incoming water • (mouth) • Oscula – a few large pores for water outlet • (osculum – singular)

13. Form and Function • Choanocytes • Flagellated collar cells to maintain a current through the canals

14. Sponges Filtering Water • http://www.youtube.com/watch?v=T7E1rq7zHLc

15. Choanocytes also trap and phagocytize food particles that are carried in the water • Phagocytize – absorption through the cell wall creating food vacuoles

16. Sponge Physiology • Feed on particles suspended in water • Detritus particles, planktonic organisms, and bacteria • Digestion is entirely intracellular • Occurs within cells • Life activities depend on current of water • A large sponge can filter 1500 liters of water a day • Some sponges can crawl at speeds of up to 4 mm per day

17. Reproduction and Development • All sponges are capable of both sexual and asexual reproduction • In sexual reproduction, most sponges are monoecious • (have both male and female sex cells in one individual) • Sperm arise from transformation of choanocytes • Sperm is released into the water by one individual and taken into the canal system of another

18. Reproduction http://www.youtube.com/watch?v=SHJOu9PjKyU

19. Reproduction and Development • Parenchymula • solid-bodied; free-swimming larva of most sponge • Sponges reproduce asexually • fragmentation • forming external buds that detach or remain to form colonies

21. Taxonomy Kingdom Animalia (animals) • Phylum Porifera (sponges) • Class Calcarea • Class Hexactinellida • Class Demospongiae

22. Class Calcarea

23. Class Calcarea • Have spicules of calcium carbonate that often form a fringe around the osculum • Have spicules that are needle shaped or three- or four rayed • Have all three types of canal systems (asconoid, syconoid, leuconoid) • Are all marine

25. Spicules

26. Class Hexactinellida

27. Class Hexactinellida • Have six-rayed, siliceous spicules extending at right angles from a central point • Spicules are often united to form network • Body often cylindrical or funnel shaped • Flagellated chambers in simple syconoid or leuconoid arrangement • Habitat mostly deep water; all marine

29. Class Hexactinellida

30. Class Demospongiae

31. Elephant Eared Sponge

32. Demospongiae

33. Class Demospongiae • Have skeleton of siliceous spicules that are six-rayed, or spongin, or both • Leuconoid-type canal systems • One family found in fresh water; all others marine

35. Demospongiae

36. Form and Function – Types of Skeleton • Major structural protein in the animal kingdom is collagen • Fibrils of collagen are found throughout the intercellular matrix of all sponges • Demospongiae secrete a form of collagen known as spongin • They also secrete siliceous spicules

38. Form and Function • Collapse of the canals is prevented by the skeleton of spicules, spongin fibers, or both • Most sponges have one of three types of canal systems – asconoid, syconoid, leuconiod

39. Form and Function – Types of Canal Systems Asconoids – Flagellated Spongocoels • Have the simplest organization – small and tube shaped • Water enters through microscopic dermal pores (ostia) into a large cavity called a spongocoel • Spongocoel is lined with choanocytes which pull water through the pores and expel it through a single large osculum

42. Leucosolenia – slender, tubular individuals grow in groups attached by a common stolon (stem) attached to objects in shallow seawater.

43. Clathrinacanariensis – bright yellow with intertwined tubes common on Caribbean reefs in caves and under ledges

44. Form and Function – Types of Canal Systems Syconoids – Flagellated Canals • Look like larger editions of asconiod, from which they are derived • Have tubular body and a single osculum which is folded back and forth to make canals • Choanocytes line certain folds called radial canals

45. Form and Function – Types of Canal Systems • Water enters the ostia into the incurrent canals • Then it moves into radial canals via small lateral openings called prosopyles • Filtered water then moves through apopyles into the spongocoel, finally exiting by the osculum • Spongocoel is lined with epithelial-type cells

48. Form and Function – Types of Canal Systems Leuconoids – Flagellated Chambers • Most complex of the sponge, which permits for increased size • Most have numerous oscula • Clusters of flagellated chambers are filled from incurrent canals and discharge water into excurrent canals that eventually lead to the osculum

49. Form and Function – Types of Canal Systems continued….. • This increases the proportion of flagellated surfaces compared to volume, providing more collar cells to meet food demands • Most sponges are leuconoids