Phylum Porifera

General Characteristics SPONGES!

Simplest of all animals _________________ No true tissues or organs _________________________ Marine and Freshwater

Saltwater are colorfulFreshwater are dull green color

General Characteristics Cont.• Sponges are sessile as adults • Free swimming larval stage called dipleurula • Porifera means pore-bearing• Water enters through pores bringing in

food and oxygen• ____________________________• Osculum- large opening at the top where

excess water leaves

Water Flow Through the

Sponge

WATER INWATER IN

WATER OUTWATER OUT

OsculuOsculumm

3 Basic Cell Types

1. _______________

2. Mesenchyme Cells

3. Choanocytes

3 Basic Cell Types• 1. Pinacocytes- flat cells that line the

outer surface of the sponge.–May be slightly contractile–____________: a specialized type of

pinacocyte; are tube-like in shape; contractile; and can regulate water circulation.

2. Mesenchyme Cells- move around in the mesohyl layer; are specialized for reproduction, secreting the skeleton, transporting/storing food.____________: jelly-like layer just

underneath the pinacocyte layer.

• 3. Choanocytes- flagellated cells that line the inner chamber of the sponge; called collar cells.–Flagellum: flagella spins to create

water currents to pull in water and food–Collar: __________________________

(plankton) from the water

Choanocyte

Choanocyte

__________________________ Consists of either one or all of the

following:Spicule: microscopic needle-like

spikes that are made of Calcium carbonate (CaCO3) or silica (glass).

Spongin: a fibrous protein made of collagen

Sponge Skeletons

SPONGINSPONGIN

Silica Silica SpiculesSpicules

Limestone Limestone SpiculesSpicules

Sponge Body Types

• 3 Kinds-–Ascon–__________–Leucon

Ascon• ____________________• Are vase-like• Least common type of sponge

________________

• Sponge wall is folded into canals• Choanocytes line the

radial canals to move water

Leucon• Have an extensively branched canal system.• ___________________________• Multiple ostia

for water to exit• Increased surface

area means more water can move through sponge

Body Forms Summary

Reproduction Sexual Reproduction- sponges are

monoecious (male and female in the same body)Release sperm and eggs into the

water from the OsculumCross-Fertilization takes place in the

ocean_____________________________

ReproductionSponge

Releasing Eggs & Sperm

Reproduction Cont’

o Sponges can regenerate (regrow) lost body parts through mitotic cell division (asexual)

o Sponges also reproduce asexually by ________________

Reproduction Cont’d

Asexual Reproduction- involves the formation of gemmules______________: resistant capsules that

sponges release to survive unfavorable conditions.When conditions become favorable, the

gemmules sprout into sponges.

gemmule

_____________________

• Phylum Porifera–3 Classes•Class Calcarea•Class Hexactinellida•Class Demospongiae

Class Calcarea

• Spicules made of Calcium Carbonate • Can have all three body forms• __________________• Ex. Grantia

Class Hexactinellida

• ___________________________• Can have syncon or leucon body

forms–Often fused into an intricate lattice–Glass sponges

Class Demospongiae

• Spicules made of silica, spongin, or both.• ____________________• Ex: common bath sponge