Phylum: PoriferaSponges

Characteristics

1. Simplest animals2. Multicellular3. No organs, tissues, or body systems4. Asymmetry (some radial symmetry)5. Sessile6. Mostly Marine7. 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 SpongeHighly folded into incurrent canals

Ex: Scypha

EX: Scypha

Leuconoid SpongeMost 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.