Phylum Porifera

SPONGESSponges are classified as animals because they are multicellular, heterotrophic, have no cell walls, and contain a few specialized cells.

Environment• Aquatic Ecosystem• Provide habitats for other marine animals• Commensalism /mutualism – form

partnerships with photosynthetic bacteria, algae, and protists that provide food and oxygen

Food Source• Filter Feeders• Digestion is intracellular

Maintaining Homeostasis - Internal(Circulation, Respiration, Excretion)

• Water moving through a sponge carries out body functions – carries nutrients and dissolved oxygen, removes wastes.

Maintaining Homeostasis - External(Response)

• No nervous system• Many make toxins to protect themselves

Movement• Larva – carried by currents before they

settle on ocean floor• Adult Sponges are sessile (do not move)

Reproduction• Sexually or Asexually• Internal Fertilization

Evolutionary Milestone• Multicellularity

• Vocabulary:– Internal Fertilization p666– Larva p666

• Page 665 Figure 26-8 or picture below: