Phylum Porifera By: Jess Edgar and Alena Thieu

Sponges

● invertebrates ● radial symmetry or are asymmetrical ● multicellular but no cell specialization ● living in fresh and marine waters

Internal● spongocoel: central cavity

○ covered with choanocytes■ flagellated cell with a collar; generate water

currents and collars trap food particles● osculum: larger openings ● spicule:

○ a needle-like structure or part, such as on of the mineral structures, supporting the soft tissue of certain invertebrates

Nervous System

● sponges do not have a nervous system; no brain, no nerve cells

● nerve net ○ a diffuse network of neurons that conducts impulses

in all directions from a point of stimulus● touch or pressure to the outside of a sponge

will cause a local contraction of its body.

● through its pores with canals that move the water to all throughout the sponge; then the oxygen from the water is used.

Respiration and Circulation

How Sponges Eat (Digestion)● Sponges are characterized by the possession of a

feeding system unique among animals.● Poriferans don't have mouths; instead, they have tiny

pores in their outer walls through which water is drawn.● Cells in the sponge walls filter bacteria from the water

as the water is pumped through the body and out other larger openings.

● The flow of water through the sponge is unidirectional, driven by the beating of flagella which line the surface of chambers connected by a series of canals.

● Heterotrophic ● Suspension feeders

● In all cases, poriferans have a canal system, through which they pump water.

● Water enters through pores called ostia, flows through canals to a chamber called a spongocoel, and finally exits through large openings called oscula.

Excretion

● A sponge has carbon dioxide and other wastes removed as the water moves in and out through the pores.

Reproduction● reproduces by budding and also sexually● hermaphorodites: individual functions as both male and

female in sexual reproduction by ● producing sperm and eggs.● dioecious: having the male and female reproductive

organs in seperate individuals. ● eggs: archeocytes (totipotent cells that have the ability

to divide and produce al the differentiated cells in an organism) or choanocytes● sperm: choanocytes

Three Distinct Groups

● Hexactinellida● Demospongia● Calcarea

Hexactinellida

● glass sponges● viewed as an early branch within Porifera● much of their tissues are syncitia, extensive

regions of cytoplasm● possess a unique system for rapidly

conducting electrical impulses across their bodies, allowing them to react quickly to external stimuli

Demospongia

● most diverse sponge group● tend to be large● brightly colored● reproduce both sexually and asexually● harvested by divers, then bleached and

marketed to be sold as bath sponges

Calcarea

● mainly live in the tropics● mainly found in shallow waters● small and dull in color

Carnivoruos Sponges● from the family Cladorhizidae● they capture small crustaceans with their spicules● spicule:

○ a needle-like structure or part, such as on of the mineral structures supporting the soft tissue of certain invertebrates, especially sponges.

● cells migrate to the organism● digestion takes place extracellularly