Download Question set 19 Bryozoa, Brachiopoda Reading: Ruppert, Fox

Question set 19
Bryozoa, Brachiopoda
Reading: Ruppert, Fox, & Barnes, pp 817; 821-829; 829-845
Lophophorata
1. How is the lophophore different from other tentacular apparatuses we have seen in other invertebrates?
2. What explanation can there be for lophophorates having a U-shaped digestive tract?
Brachiopoda
3. How does the shell of brachiopods compare to that of bivalve molluscs? How is its mode of opening
and closing and means of attachment different from that of the bivalve-molluscan shell?
4. Like bivalves, brachiopods have expanded the ancestral filter-feeding surface. How?
Bryozoa
6. How does a zooid of a bryozoan compare to a polyp of a cnidarian?
7. How does a colony of bryozoans compare to that of a hydroid? How is its organization different in
terms, for example, of the relationship among zooids?
8. How does polymorphism in bryozoans compare to that in hydrozoans?
9. While other invertebrates we have studied use the coelom in locomotion, particularly burrowing, bryozoans use it to protrude and retract the polypide (the protrusible parts of the body, including the
lophophore) out of and into the cystid (the box-like protective housing). How does this protrusion
mechanism work?
10. How do bryozoans feed? How is this mechanism different from other ciliary suspension-feeding mechanisms in other animals?
11. How does regeneration play a role in excretion in bryozoans?
12. How does sexual reproduction accomplish dispersal in bryozoans?
13. What kinds of asexual reproduction do bryozoans show?
Question set 20
Hemichordata; Chordata: Urochordata
Reading: Ruppert, Fox, & Barnes, pp 857-865; 931-932; 940-959
Chordata: Urochordata
1. What features distinguish the chordates, including the vertebrates as well as the invertebrate chordates,
from the other invertebrates? How can the apparent upside-down morphology of chordates, such as
the dorsal position of the nervous system and the flow of blood (toward anterior in the main ventral
vessel), be explained?
2. How does the structure of larval tunicates show that tunicates are related to vertebrates? What
explanation is there for how un-vertebrate-like adult ascidians are?
3. How are individuals among solitary, social, and compound tunicates related to one another?
4. Identify ways in which the cuticle of tunicates is strange, so unlike that of other invertebrates.
5. How do tunicates feed? How, specifically, do pharyngeal gill slits play a role in feeding?
6. How have thaliaceans and larvaceans adapted to a pelagic lifestyle, so unlike their sedentary relatives
among the ascidians?
Hemichordata
7. Deuterostomes, including hemichordates, chordates, and echinoderms, have a tripartite coelom. How
is this tripartite coelom manifest in hemichordates? How does it arise in the developing enteropneust?
8. How do acorn worms feed? How, specifically, is food gathered, ingested, and digested?
Question set 21
Echinodermata: biology, Asteroidea
Reading: Ruppert, Fox, & Barnes, pp 873-876; 876-889
1. How do echinoderms actively control their connective tissue so that it can fairly rapidly change between
stiff and fluid states, and what use is this control?
2. How, in general, do echinoderms develop their pentamerous symmetry? Was the deuterostome ancestor
that gave rise to echinoderms pentaradial? What advantage do echinoderms (or did their most recent
common ancestor) gain by adopting pentamerous symmetry?
3. Like other deuterostomes, echinoderms have a tripartite coelom. How do these coelomic compartments
arise in development and what function does each serve in the adult?
4. What skeletal support do echinoderms like asteroids have and what is the relation of this skeleton to
cuticle? How does it compare to the calcareous skeletons of other invertebrates we’ve studied?
5. What role do ossicles play in defense as well as in general skeletal support of the body?
6. What is the form of the water-vascular system in an echinoderm such as a sea star, and what role does
it play in circulation and locomotion?
7. What other coeloms play a role in circulation in echinoderms? Particularly for asteroids, how are fluids
circulating respiratory gases used?
8. Podia are made for walking in most asteroids. How? (How do they work?)
9. How do the nervous and digestive systems reflect the pentamerous symmetry of the asteroid body?
10. How do asteroids such as Asterias open mussels? What role does the mutable connective tissue play
in this? What other ways do asteroids have of feeding?
11. How do the larvae of asteroids feed?
Question set 22
Echinodermata: Ophiuroidea; Echinoidea
Reading: Ruppert, Fox, & Barnes, pp 889-896; 896-909
Ophiuroidea
1. While asteroids walk with their tube feet, ophiuroids move with their arms. How? In particular, how
is the skeletal system of the arms modified for this kind of leaping, lurching locomotion? How are the
tube feet different?
2. What different modes of feeding do brittle stars use? In particular for suspension feeding, how are the
arms and their spines and tube feet used? How do carnivorous brittle stars use specialized ossicles for
handling prey?
3. What special respiratory organs do ophiuroids have? What other functions do these organs serve?
Echinoidea
4. Judging by the position of ambulacra in sea urchins, where would you say their arms went? (That is,
the ancestor of echinoids must have had arms more like a sea star, so what is their correlate in the
globose body of present-day urchins?)
5. How do pedicellariae of urchins compare to those of asteroids?
6. If the body wall in echinoids is composed of the same layers as that of asteroids, as the textbook
says, how is the body so much like a globe? How do the ossicles of the test compare to the ossicles of
asteroids?
7. How do urchins move? (See also, the video showing an urchin escaping from, it thinks, a predatory
sea star.)
8. How do the coeloms of urchins play roles in respiration?
9. How do sea urchins use the so-called Aristotle’s lantern in feeding?
10. How do sand dollars qualify as selective deposit and suspension feeders? What advantage does being
“irregular” (that is, bilaterally symmetrical) have for this kind of urchin?
Question set 23
Echinodermata: Holothuroidea; Crinoidea
Reading: Ruppert, Fox, & Barnes, pp 909-924
Holothuroidea
1. Being worm-like, holothuroids have evidently secondarily adopted bilateral symmetry. What advantage
does this bilaterality give them? What evidence remains of pentamery?
2. How do sea cucumbers use their special buccal podia in suspension and deposit feeding?
3. What special respiratory organs do holothurians have?
4. What purpose does spontaneous evisceration serve in sea cucumbers?
Crinoidea
5. Crinoids, particularly sea lilies, are rather sedentary, but video of a sea bed at 400 m depth shows a sea
lily virtually galloping along (see Science News, http://www.sciencenews.org/view/generic/id/6711/title/
Great Galloping Crinoids Lilylike sea animal takes a brisk walk, describing this work of T. Baumiller
and C. Messing. [video on Web site]). How mobile are the feather stars? (How do they move?)
6. On what and how do crinoids feed? How is this different from the suspension-feeding mechanisms of
the ophiuroids?