L6 - porifera

Question 1

sponges

why no terrestiral?

Answer 1

not terrestrial because need water to filter feed.

Question 2

4 classes of porifera

Answer 2

calcacarea
demospongiae
hexactinellida
hemoscleromorpha

Question 3

basic morphological features

- defined by lack of features

Answer 3

- no true tissue
no mouth/gut
no muscles. 
maybe osculum = sensory 
no axes of symmetry.

Question 4

features present

Answer 4

water canal system
mesohyl
internal skeleton = spicules/spongin.
cells autonomous, show totipotency/pluripotency

Question 5

water channel system in sponge
A- incurrent pore name?
B- outcurrent pore? 
C-what is spongocoel? 
how is movement of water thru body achieved?

Answer 5

A in = ostia
B out = oscula
C water-filled central cavity
choanocytes, flagellated, w collar beat water thru/

Question 6

3 major body plans

Answer 6

ascanoid - single flagellated pumping cavity
sycanoid - many flagellated canals radiate from spongocoel
leucanoid - many flagellated chambers connected by passive canals

Question 7

5 cell types in sponges

Answer 7

pinacocytes 
archaocytes
myocytes
prorocytes
choanocytes

Question 8

pinaocoyte function

Answer 8

flat cells cover outer body = pinacoderm.

not true epithelium bc lack basil lamina.

Question 9

archaeocytes - amoebocytes

Answer 9

totitpotent - make spicules, spongin or transport food to vacuoles.

Question 10

myocytes

Answer 10

contractile cells. open and close oscula.

Question 11

porocytes

Answer 11

tubular cells form opening to ostia in some groups

Question 12

choanocytes

Answer 12

pumping, feeding, transform into sperm (pluripotent)

– look like choanoflagellate protists

Question 13

skeletons

Answer 13

spongin = fibrillar colagen

spicules - calcium carbonate or silicon dioxide.

Question 14

feeding of sponges

Answer 14

choanocytes capture food, beating flagella draw water in. large particle trapped, phagocytozed.
pinococyte and ameobocyte opportunistically phagocytose food particles coming into choanocyte cell body.
- some harbour photosynthetic endosymbionts.
- some are carnivourous.

Question 15

sponge sneeze.

Answer 15

danger with getting clogged with sediment = cilia @ oscula triggered by water flow. communicate w myocyte to induce strong contraction of oscula

Question 16

reproduction of sponges

Answer 16

asexual (budding & fragmentation) and sexual.
sequentially hermaphroditic.
choanocytes => sperm. broadcast spawning. both egg and sperm released in water column. larva develop and swim before settlement. feed by lecithotrophy

Question 17

lecithotrophy?

Answer 17

getting all food from yolk supply.

Question 18

repair and recognition

Answer 18

amoebocytes go to missing area and repair sponge.

- evidence of immune response. can recognize self vs non-self.

Question 19

define hermaphroditism

Answer 19

individual is both male and female

Question 20

define protandry

Answer 20

male first, female later

Question 21

define protogyny

Answer 21

female first, male later

Question 22

fertilization?

Answer 22

external - if released in water column

internal - if only sperm is broadcast, eggs may be brooded

Question 23

larvae - swim briefly, food?

Answer 23

lecithotrophy

Question 24

define lecithotrophy

Answer 24

get food form yolk supply

Question 25

embryos go thru what kind of cleavage?

Answer 25

radial