Zoology Test 2 Flashcards
ctenophores:
have not advanced beyond the tissue grade of organization
Not a characteristic of Phylum Platyhelminthes?
epidermal muscles
the epidermal cells in ctenophores that function in prey are called:
colloblasts
the flame cells or protonephridia of Platyhelminthes & rotifers:
function in osmoregulation and possibly waste removal
mesoderm arises:
during blastopore formation (gastrulation)
Tissues such as those found in parasitic platyhelminthes seem to violate the cell theory because the nuclei are not separated by cell membranes. The term used to describe these is:
syncytial
the flukes in the class Monogenea:
are mostly ectoparasites
the planarian (class turbellaraia) feeds by:
scraping and sucking food particles via a midventral proboscis
head region of a tapeworm (class cestoda) is called:
scolex
some parasites such as chlonorchis exhibit complex life cycles with many hosts and larval forms. Why do they do this?
to increase transmission rates & also so larval forms don’t compete with adults for same resources
animals that have three layers of embryonic tissue but have organs in a cavity that is not completely lined with mesoderm are:
pseudocoelomate
difference between schizocoelous and enterocoelous organism is
difference in how the true coelom forms from mesoderm: form the gut or blastopore region
where would you locate the coelomic cavity when dissection a mollusk such as a clam?
the small cavity around the heart, kidney and lumen of the gonads
which arose first in gastropods, coiling or torsion?
coiling
a synapomorphy of all bivalves is:
no radula
ctenidia are:
used for gas exchange
the siphon in cephalopods is derived from the:
foot
circulatory system of a squid is:
closed
fastest means of cephalopod locomotion is
water (jet) propulsion
the more advanced prosobranchs have only one …… in their mantle cavity
gill
coiling in gastropods:
occurs when the mantle secretes more calcium carbonate on one side of the body versus the other
coiling in cephalopods
occurred independently of coiling in gastropods
which subclass of gastropoda do the nudibranchs belong to?
opisthobranchia
snails that lack gills are called “pulmonate” and their mantle cavity functions:
as a lung
the water current in the body of a cephalopod mollusk provides:
oxygen for respiration, jet power for rapid locomotion, a means for carrying wastes and gametes out of the body
what is the advantage of the complex gut and muscular pharynx found in “advanced” Turbellarians?
increases surface area for digestion
what is paedomorphosis?
retention of ancestral juvenile traits in adult body forms
How many times has the eucolomate body plan evolved in animals?
3
