Phylum Porifera - Sponges

Question 1

What habitat do sponges live in?

Answer 1

Aquatic, mostly marine

Question 2

Locomotion type

Answer 2

None, sessile. Larvae may be planktonic

Question 3

Tissue layers and organization

Answer 3

• Two cell layers (not diploblastic), simplest multicellular animal with loose aggregation of cells
• No basal membrane

Question 4

What are the cell layers in a sponge?

Answer 4

Outer - Pinacocytes
Inner - Choanocytes
Intermediate - Mesohyl

Question 5

What is the sponge skeleton composed of?

Answer 5

Spicules (calcareous or silicious) and collagen fibers (spongin)

Question 6

Sponge symmetry

Answer 6

No symmetry, maybe radial

Question 7

Digestion

Answer 7

intracellular, no organs or tissue

Question 8

Gas exchange

Answer 8

Diffusion

Question 9

How does digestion occur? Steps.

Answer 9

Water carrying food particles enters through porocyte or canal (drawn in from choanocyte flagella current) then taken up by choanocyte and shared with mobile amoebocytes that share with rest of animal cells

Question 10

Pinacocytes

Answer 10

External cell layer
Protective structure
Forms pinacoderm

Question 11

Porocyte

Answer 11

Pore cell for water entry

Only in Asconoid (simple) sponges

Question 12

Choanocytes

Answer 12

Lines internal cell wall
Creates feeding currents with flagella
Engulfs food particles

Question 13

Mesohyl

Answer 13

Gelatinous protein matrix
Between pinacoderm and choanocytes
Contains skeletal material and ameboid cells

Question 14

Archeocytes (amoebocytes)

Answer 14

Digestion and feeding

Precursor to other cells

Question 15

Spicules

Answer 15

Skeletal structures of mesohyl
Calcareous or Silicious
Distinguishing characteristic used in ID

Question 16

Ostium

Answer 16

Pores for incoming water (syconoid and leuconoid)

Question 17

Osculum

Answer 17

Large openings for water to exit

Question 18

Spongocoel (atrium)

Answer 18

Central cavity (lined with choanocytes)

Question 19

What are the 3 sponge types?

Answer 19

Asconoid, Syconoid, Leuconoid

Question 20

Which sponge classes have Silicious spicules?

Answer 20

Hexactinellida and Desmospongiae

Question 21

Reproduction

Answer 21

Monoecious (hermaphrodite)

Sexual and Asexual

Question 22

Sponge sexual reproduction

Answer 22

Sperm produced in mesohyl
Taken up by choanocytes of a compatible sponge
Amoebocytes transport to mesohyl
Fertilizes eggs in mesohyl

Question 23

Where does sponge development take place after fertilization?

Answer 23

Internally in receiving sponge or released to water column

Question 24

How does sponge asexual reproduction happen?

Answer 24

Formation of external buds, gemmules (may or may not detach)
-Usually freshwater and some marine
Internal buds with protective coating

Question 25

5 facts about Class Calcarea

Answer 25

• Calcareous Spicules
• Spicules straight monoaxons or 3-4 rays
• Small, more primative
• Tubular or vase-shaped
• All three levels of structure

Question 26

What are the three levels of structure in sponges?

Answer 26

Asconoid, Syconoid, Leuconoid

Question 27

5 Facts about Class Hexactinellid sponges

Answer 27

• Spicules 6-rayed and silicious
• Spicules form glass-like lattice
• Likely radially symmetric
• Size ranges 7cm-1m
• Deep water habitats

Question 28

6 facts about Class Desmospongiea

Answer 28

• Largest class
• Spicules silicious, some have spongin or both
• All leuconoid
• Marine, one freshwater family
• Encrust, and bore and have variety of shapes
• Can grow very large

Question 29

4 Facts about Class Sclerospongiae

Answer 29

• Small class
• Spicules silicious with spongin and secrete a calcareous basal skeleton
• Leuconoid structure
• Habitat: caves, crevices, or deep water

Question 30

5 Facts about Sponge Reefs (glass)

Answer 30

• Limited distribution as unusual relics in BC waters (so far)
• High silica for skeletal structure in North Pacific
• Important nursery habitat for verts and inverts
• Impacted by bottom fisheries and trawling
• MPA’s for protection in progress