ch 24: echinodermata Flashcards
deuterostome development (4)
- radial and indeterminate cells
- folds on archenteron form coelom
- anus develops from blastopore
- nerve cords on dorsal side
echino circ sys
closed
what type of sym do echino larvae hacve
bi
what type of sym do adults have
pentaradial
what is a polian vesicle
dead end of the WVS
3 uses for the WVS
- feeding
- locomotion
- gas exchange surface
what can alter the connective tissues hardness/fluidity
the nervous sys
class stelleroidea (3)
- sea stars
- brittle stars
- basket stars
class echinoidea (2)
- urchins
- sand dollars
class holothuroidea
sea cuces
stelleroidea defining feat
arms radiate from central disc
2 feats if asteroidea/sea stars
- arms thick and not used for locomotion
- predators
4 functs of tube feet
- locomotion
- hold and pull apart prey
- excretion
- resp
stelleroidea feeding (2)
- evert stomach to externally digest prey
- release digestive enzymes (pyloric cecae)
3 protection feats in stelleroidea
- calcareous plates/ossicles
- ambulacral ossicles protect vessels and nerves of the arms
- pedicellariae = pinching jaws
stelleroidea nerves (2)
- uncentralized nerve net
- tube feet at arm tips sense chemicals and light
dermal branchiae in stelleroidea
skin gills - extra area for gas exchange
do stelleroidea do asexual repro?
yes; budding
stelleroidea fert
open
weird thing about bilateral sea star larvae
rudiment forms at the expense of the rest of the larvae until it takes over and becomes the animal
ophiuroidea (2)
brittle and basket stars
3 diffs ophiuroidea have from asteroidea
- arms thinner and more obviously segregated from central disc
- move w/ arms
- arms can drop off at will and regenerate
ophi feeding (4)
- deposit
- suspension
- carnivores
- scavengers
ophi eating (2)
- tube feet bring food to mouth
- buccal podia and jaws compact food into pellets
no ophi have an anus?
no
bursae in ophi functs (3)
- resp
- excretion
- openings for gonads
what is the bursae analgous to
mantle cavity
test
a living “shell” which is a fusion of calcareous plates covered in ciliated epithelium and sometimes spines
spine feats echinoids (4)
- wedging body into crevices
- manipulating food
- defense
- can be replaced
what 2 feats in echinoids are elongated
- tube feet
- pedicellariae
urchins eat (3)
- bryozoans
- detritus
- algae
urchin mouthparts
aristotle’s lantern consisting of 5 teeth
sand dollar feeding
capture diatoms and detritus and use mucus to draw them into mouth
sand dollar resp
via tube feet and thin projections around mouth
echino larvae
echinopluteus larvae
sea cuces 5 rows of tube feet
- 3 ventral rows for locomotion
- 2 dorsal rows for resp
holothuroidea skeleton
reduced to ring around pharynx and lil bumps in body wall
what 2 things do sea cuces not have
- ambulacral ossicles
- madreporite
holoth resp
resp tree
feeding tentacles in holoth are modified
buccal podia
holoth defense (4)
- evisceration
- cuverian tubules
- toxins in body wall
- dig, hide, camo
2 functs of evisceration
- may deter predators/distract/satisfy
- rids body of toxins
3 feats of cuverian tubules
- can shoot out anus
- toxic and sticky
- detach and regenerate
2 ways to repro in holoth
- asexual transverse fission and regeneration
- sexual: open fert
2 crinoid feats
- capture suspended particles w/ tube feet and pass to mouth via cilia
- WVS radial canals are in pinnules
crinoid repro (3)
- separate sexes
- gonads in pinnules
- open fert
