Ch 4: Phylum Porifera

Question 1

4 defining features of Porifera

Answer 1

1. absence of gut muscles
2. functional parts of body uniformly distributed thru body
3. no symmetry
4. sessile filter-feeders

Question 2

Porifera body plan

Answer 2

porous cup with 2 epithelial layers and jelly-like connective tissue in the middle

Question 3

Do sponges have basal lamina?

Answer 3

no; cells are not linked to neighbours, allowing tissues to reorganize and the body shape to change

Question 4

sponge epithelium

Answer 4

• inner surfaces lined with choanocytes

- outer surfaced formed of flattened contractile pinacocytes

Question 5

choanocytes function (4)

Answer 5

generate water movement, capture food (via phagocytosis), capture incoming sperm, may give rise to gametes

Question 6

connective tissue, the mesohyl

Answer 6

living cells in a gelatinous ground substance and collagen fibers

Question 7

function of cells in the mesohyl (4)

Answer 7

1. digest food particles caught by choanocytes
2. store food
3. eliminate wastes
4. transform into other cells

Question 8

what other types of cells can amoebocytes turn into? (4)

Answer 8

1. sclerocytes
2. spongocytes
3. gamete producing cells
4. cells that act like muscles and regulate the size of the osculum

Question 9

what do sclerocytes produce?

Answer 9

spicules

Question 10

asconoid choanocytes location

Answer 10

line the spongocoel

Question 11

syconoid choanocytes location

Answer 11

line pores leading to the spongocoel

Question 12

leuconoid choanocyte location

Answer 12

line special chambers (most SA/common)

Question 13

sponges’ 2ndary metabolites aid in defence (3)

Answer 13

• toxic to predators
• inhibit algal growth
• inhibit setting of larval inverts

Question 14

what are sponge colours due to?

Answer 14

• pigments

- endosymbionts

Question 15

3 examples of body wide coordination without nervous tissue

Answer 15

1. food is shared
2. gametes produced simultaneously all over
3. several oscula can close at once

Question 16

how are 2 ways this body wide coordination could be possible w/out a nervous system?

Answer 16

1. individ cells responding to the same stimulus simultaneouslt
2. conduction by non-neurons

Question 17

asexual repro (3)

Answer 17

1. budding
2. broken pieces can regenerate
3. gemmules produced by some freshwater sponges

Question 18

what are gemmules?

Answer 18

• time capsules for surviving bad times

- a spicule covered bag of archeocytes/amoebocytes

Question 19

sexual repro steps (5)

Answer 19

1. eggs/sperm prod by amoebpcytes
2. sperm out via osculum and consumed by other sponges
3. eggs retained in mesoglea
4. planktonic amphiblastula larvae released
5. attach to substrate and metamorphose

Question 20

calcarea features (3)

Answer 20

• CaCO3 spicules
• marine, mostly deepwater, small
• includes all 3 structural types

Question 21

desmospongiae features (3)

Answer 21

• spongin and/or silica spicules
• 80-90% of freshwater sponges
• almost all leuconoid; some can become very big

Question 22

hexactinellida features (4)

Answer 22

• silica spicules, usually w/ 6 perpendicular rays
• mostly deepwater and tropical
• living tissue is large strands of giant, multinucleated cells
• food collected by multiple collars on that “tissue”

Question 23

placozoa features (4)

Answer 23

• usually <5mm
• w/out well organized tissue
• upper and lower epithelial-like layers w/ intercellular junction
• eat algae