Biology, Eighth Edition (Raven)

Chapter 34: Coelomate Invertebrates

Post Test

Why are gastropods not internally bilaterally symmetrical like other molluscs? (p .658 )
A)because the internal organs on one side degenerate
B)because of embryonic torsion
C)because of abnormal coelom formation
D)because of coiling of the shell
E)it is not understood
In what way do earthworms differ from most polychaetes? (p. 663)
A)they are parasitic
B)they have a reduced number of segments
C)they are hermaphroditic
D)they undergo asexual reproduction
E)both a and b
A lophophore is: (p. 664)
A)a phylum of animals.
B)a pore for exchange of water.
C)a structure found in trochophore larvae.
D)a circular ridge around the mouth bearing one or two rows of cilliate tentacles.
E)none of the above
Some insects show complete metamorphosis where the larva is totally different from the adult. What is the advantage of this over incomplete metamorphosis where the juveniles are just smaller versions of the adult form? (p. 675)
A)there is no advantage
B)it allows the larva to use different food sources than the adult
C)these insects can grow larger
D)the adults can disperse large distances and find good food sources in which to lay eggs
E)both b and d
Echinoderms show pentaradial symmetry but they are thought to have evolved from bilaterally symmetrical ancestors. What is the evidence for this? (p. 676)
A)the fossil record
B)all other deuterostomes are bilaterally symmetrical
C)their larvae are bilaterally symmetrical
D)homology of the water vascular system with other deuterostomes
E)all of the above
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