SPONGES:

LIFE FUNCTIONS P1, 5

Wide view of sponges

sponges

Phylum Porifera: Sponges

• Porifera means “pore-bearing”

• Simplest animals no symmetry

• No tissues, no organs • 2 layers of undifferentiated cells:

1. Endoderm – inner layer

2. Ectoderm – outer layer

• B/w 2 layers is jellylike material called mesenchyme

• Permanently attached to bottom sessile & benthic

• Filter feeders collect plankton, algae, bacteria, detritus

Basic Body Form/Organization

1. Osculum – large

excurrent pore

2. Ostia – small incurrent

pores

3. Inner chamber –

collar cells

(choanocytes) line

chamber; absorb O2 &

nutrients

1

2 3

Purple tube sponge

Osculum

Life Functions

• Ingestion/Digestion

1. Flagella create water

currents

2. Collar trap food

particles

3. Cell body engulfs &

digests food

• Cells found in mesenchyme

called amebocytes also

ingest & digest food

• Digest occurs in food

vacuoles

Encrusting sponge

Ostia

COLLAR CELLS LINE CHAMBERS

WATER ENTERS OSTIA ON SIDES & EXITS THROUGH OSCULUM AT TOP

Life Functions (cont’d)

• Respiration

• Sponge cells in direct contact w/

water gas exchange occurs

across cells

• O2 comes in t/ ostia, CO2

diffuses out & expelled t/ oscula

• Sensitivity

• No tissues, no organs no

nervous system

• Muscle-like cells called

myocites can contract & close

ostia

• Protects sponge from taking in

toxic substances

Jonathan Birds: Sponges! Video

https://www.youtube.com/watch?v=m8a0oNsDEx8

LIFE CYCLE OF THE

SPONGE P1, 5

Sexual Reproduction

1. Adults release sperm & eggs into water

2. 1 sperm + 1 egg fertilization 1 zygote (S1)

3. Cell division (cleavage) 2-celled, 4-celled,

etc. (S2)

4. Solid ball of cells formed morula (embryo)

(S3)

5. Hollow area develops blastula (S4)

6. Cells develop flagella & can swim larva (S5)

7. Contact w/ hard substrate & attaches (S6)

8. Develops into adult sponge (S7)

Sexual Reproduction (cont’d)

• Can be male, female, or have both reproductive organs

• Hermaphrodites – animals that possess both ovaries &

testes

• Hermaphrodite sponges produce sperm & egg at different

times no self-fertilization

Asexual Reproduction

• Pieces of sponge may break off can grow into whole

new sponge

• Regeneration – a mode of reproduction in which a whole

body can be regrown from parts of a parent body

SPONGE ORGANIZATION

& DIVERSITY

P1, 5

Organization of Sponges

• Some sponges have a rigid structure made of spicules (splinter-like, spiny structures)

• Made of calcium carbonate or silicon dioxide

• Unique in each species

• Few animals eat sponges

Organization of Sponges (cont’d)

• Some sponges have elastic framework of protein fibers

called spongin

Sponge with spicules

Calcareous Sponges

•Very small sponges

•Spicules made of

calcium carbonate

•Spicules are

separate &

unsupportive

Silica Sponges

•Large sponges

• “Glass” sponges

•Spicules made

of silicon dioxide

•Spicules fused &

offer support

Euspongia (bath sponge)

Cliona (boring sponge)

Euplectella (tubular sponge)

Ircinia (vase sponge)