Phylum Porifera

1
Phylum Porifera

• General Features
• Sessile
• pore-bearing
• collar cells (choanocytes)
• Filter feeder
• 5000 species (most marine)

2
General Features, cont.

• Some radially symmetrical many irregular
• Often with noxious odor
• Skeleton rigid or fibrous
• Rigidcalcareous or siliceous spicules
• Fibrouscollagen (spongin)

3
3 Classes of sponges

• Calcarea
• calcium carbonate spicules
• Hexactinellida (glass sponges)
• siliceous spicules
• Demospongiae
• siliceous or spongin spicules, or both

4
Sponge Form and Function

• Dermal ostia (body pores)
• Flagellated choanocytes trap food
• Water exits through osculum

5
Types of canal systems

• Asconoids
• flagellated spongocoels--simple
• Syconoids
• prosopyles and apopyles in flagellated radial
  canals
• Leuconoids
• large, complex, greater surface area for feeding

6
Types of Cells

• Mesohyl
• Connective tissue, gelatinous matrix
• Choanocytes
• Engulf food
• Archaeocytes
• Digest food can differentiate
• Pinacocytes
• Similar to epithelial cells

7
Asexual Reproduction

• Regeneration of lost parts repair injuries
• External budding
• Internal budding (gemmules)
• Survive drought, freezing

8
Sexual Reproduction

• Most monoecious
• Free-swimming ciliated larva
• Some release sperm into water some release sperm
  and oocytes

9
Calcarea Characteristics

• Spicules of calcium carbonate, 3-4 rays
• Small
• Tubular or vase shaped
• Asconoid, syconoid, and leuconoid
• Leucosolenia, Sycon

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Hexactinellida Characteristics

• Glass sponges
• Spicules of silica, 6 rays
• Most deep-sea forms
• Syconoid and leuconoid forms
• Filter feeding accomplished by unique syncytial
  tissue

11
Demospongiae Characteristics

• 95 of living sponge species
• Spicules of silica
• If absent, skeleton of spongin
• Leuconoid
• Almost all marine

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Phylogeny Adaptive Radiation

• Classes distinguished based on spicule form and
  chemical composition
• A family of Demospongiae dwelling in deepwater
  caves has adapted a carnivorous feeding mechanism
  to trap crustaceans