Phylum Porifera - sponges

Question 1

Protostome or Deuterostome?

Answer 1

Protostome

Question 2

Dipl or Tripl

Answer 2

Dipl

Question 3

Digestion

Answer 3

• they’re suspension/filter feeders: sit & wait for food to come to them
• 2 ways to increase efficiency
• 1. increase surface area of filter
• 2. increase rate of flow (more water)

Question 4

Respiration

Answer 4

no specialized respiratory organs (no lungs)
every cell is responsible for its own gas exchange

Question 5

Excretion

Answer 5

no specialized excretory organs, e.g. kidneys (get rid of metabolic waste)

Question 6

skeleton

Answer 6

• composed of:
• spongin – flexibility
• spicules – rigid, poky bits, act as connecting points in structure, maybe defense?
• Spongocoel – empty space, form of hydrostatic skeleton: has water pressure & squishable
• endoskeleton – support structure covered by living cells

Question 7

Symmetry or Assymetry?

Answer 7

assymetry: only phylum that has it

Question 8

Level of Organization

Answer 8

cellular level of organization

Question 9

Nervous system?

Answer 9

no nervous system – lack neurons, if u poke it doesn’t know

Question 10

Circulatory System?

Answer 10

no circulatory system – no blood vessels
not necessary b/c every cell does its own diffusion

Question 11

Three Cell Types

Answer 11

1. ectoderm → pinacocytes
2. endoderm → mesenchyme cells (maintain skeleton & immunity)
3. endoderm → choanocytes (responsible for feeding)

Question 12

Body Types:

1. Ascon

Answer 12

water enters through dermal pores → spongocoel (water filtered, contains choanocytes) → osculum

Question 13

Body Types:

2. Sycon

Answer 13

• water enters through dermal pores → incurrent canals → prosopyle → radial canals (water filtered here; made of choanocytes) → apopyle → spongocoel → osculum
• why complex?
• Surface area, increase area of filter to become more efficient
• However, when eaten, more difficult to grow back

Question 14

Body Types

3. Leucon

Answer 14

• water enters through dermal pores → incurrent canals → choanocyte chambers (water filtered here) → excurrent canals → oscula
• complex
• Leucon is only body type that’s horizontal, e.g. it grows across a rock

Question 15

Reproduction:

Asexual

Answer 15

• Budding – create another version of yourself attached to you & fall off & do own thing
• gemmules (fall season) – create capsultes w/ archeocytes (mesenchyme), protected during winter
  
  • in spring, gemmules break open & can create ~ 50 sponges

Question 16

Reproduction:

Sexual

Answer 16

• motile larvae (mesenchyme cells) → flagellated larva (can swim)
  
  • this reduces competition btn parent & adult offspring
  • this reduces competition btn larval offspring & parent
• parent lives on rock, offspring can move → thus, not competing
  
  • typical of one stage travelling great distance & another can’t
  • e.g. butterfly & caterpillar