Phylum: Porifera Sponges

Characteristics Simplest animals Multicellular No organs, tissues, or body systems Asymmetry (some radial symmetry) Sessile Mostly Marine Home for many organisms

Shape/Size Thin flat crust, vase-shaped, branched, or irregular

Colors Yellow, orange, green, purple Their color fades quickly when removed from water

Anatomy Osculum – opening at the top where water exits Spongocoel – large chamber Ostia – pores for incoming water Pinacocytes: located on the epidermis; regulate the size of the ostia Spicules – skeleton, support and protect Holdfast- base where sponge attaches to rock or surface

Anatomy Choanocytes (collar cells) – flagellated collar cells lining the inside canals, maintain current of water, they trap and phagocytize food particles Mesoglea– gelatinous “connective tissue” layer between cells Amoebocyte – transports nutrition from cell to cell

Spicules

Three Classes of Sponges Class Calcarea spicules of calcium carbonate Class Hexactinellida spicules of silica fused in a continuous and often very beautiful latticework Class Demospongiae the largest class, which has unfused silica spicules, OR a tough, keratin-like protein called spongin, OR a combination of the two  

Calcarea

Hexactinellida

Demospongiae

The Three Main Types of Organization Asconoid Sponge: Simple Sponges Most Simple Sponge Example: Leucosolenia

Sychonoid Sponge Highly folded into incurrent canals Ex: Scypha

Leuconoid Sponge Most complex Large size Incurrent and excurrent canals Ex: Bath Sponge

Obtaining food and Digestion Filter Feeders: trap microorganisms (plankton and bacteria) Choanocyte collar collects food with fingerlike microvili (cillia) and flagella Cellular Digestion: Food particles will be broken down by choanocytes and move onto Amoebocyte where the nutrients will be transported

Reproduction Sexually Hermaphroditic – both male and female sexes are in one body Ova are fertilized by motile sperm (sperm arise from choanocytes) Zygotes develop into flagellated larva

Asexual: Budding/fragmentation – external buds of tissue drop off of parent

Asexual: Regeneration of body parts

Asexual: Gemmules – internal buds (dormant), masses of cells that are encapsulated and surviv3 periods of harsh conditions (i.e. winter)

Locomotion Adult is sessile Larva are flagellated

Sponge Industry Mediterranean, Gulf of Mexico Brought up by divers or dredges Living cells are allowed to decay, they are cleaned, dried, and marketed.