Porifera Study

From colonial protists to multicellular animals.

colonial chanoflagellate

The animal kingdom is considered “monophyletic,” meaning it has a

single common ancestor.

Porifera is thought to be a “dead

end” clade, meaning no other

forms are evolved from them and

they remain much as they have

been for millions of years.

Basic Body Form of Sponges

Sac-like structure consisting of 3 parts:

1. epidermal cells

2. specialized cells

3. amoeboid cells

Sponges have no true tissues.

However, they do have

specialized (differentiated) cells

which perform specific

functions important to the

survival of the entire organism.

CollarChoanocyte

Ameobocyte

• collar: microvilli net that filters food

particles

• choanocyte: beats flagellum and

ingests trapped food particles

• ameobocyte: aka mesenchyme cells,

serve multiple functions

phagocytosis

distribute food and oxygen using

pseudopods

sclerocytes: produce spicules

chromocytes: produce pigments

archeocytes: undifferentiated cells

(stem cells)

food particles

food vacuole

Asconoid sponges

Simplest structure.

No folding of body wall.

Scyconoid Sponges

Advanced structure.

Folded body wall.

Increases surface area.

Leuconoid Sponges

Complex structure.

Highly branched and folded.

Increased surface area.

Allows for larger organism.