Zoology Test 1 Flashcards
A phylogeny is different from a cladogram…
because it includes time since divergence
if convergent characters are used to group taxa then …….. groups are produced.
polyphyletic
how are outgroups used by taxonomists?
to determine the polarity or direction of evolutionary change in character states
the ability to use biochemical data to form phylogenetic trees is based on the assumption that………
all life uses similar sequences of DNA
an argument in favor of the colonial flagellate theory for the origin of multicellular animals is…..
it is well supported by observations of metazoan development
Diploblastic organisms lack which germ layer(s)?
mesoderm
Which is the correct developmental sequence? & how much time elapses between beginning and end?
Fertilization > cleavage > blastulation > gastrulation
happens in a few hours
the blastocoel is:
the fluid filled center of a blastula
a cell taken from a protostome embryo:
stops proper development as does the remainder of the embryo
at the end of cleavage, the zygote is:
the same size as when it began
during cleavage:
the number of cells in the zygote increases dramatically
sponges exhibit:
the cellular level of organization
the most advanced sponge body plan is:
leuconoid
specialized feeding cells found in sponges are called:
choanocytes
a drop of ink placed in the water around a sponge would pass through the sponges structures in what order?
osita > spongocoel > osculum
Study of hawks-bill sea turtle stomach contents found that sponges were a major portion of their diet. Sponges are usually protected from predators by protective structures called:
spicules
cells that move about in the mesohyl of sponges, digest particles, and may specialize for other functions are the:
archaeocytes
reproduction in sponges is:
asexual by budding, asexual by gemmules, sexual with both male and female sex cells in one individual and asexual by fragmentation
Why are bath sponges so soft?
bath sponges are composed primarily of softer spongin
nematocysts are:
stinging organelles
metagenesis is:
an alternation between sexual and asexual generation
rhopalia are:
sense organs for orientation and detecting light
the velum of hydrozoans and the velarium of cubozoans are:
independently derived characters
reef building corals:
are hexacorallian corals and have symbiotic zooxanthellae
The …….. stage is best adapted for cnidarians living in colonies while the …. stage helps in dispersal and survival in open oceans.
polyp, medusa
throughout most cnidarian groups, the basal or pedal disc serves to
attach the cnidarian to the substrate
the class of radiate animals with the most conspicuous medusa stage is:
scyphozoa
the presence of ameboid cells and fibers in the mesoglea, as well as lack of a velum, would indicate that a medusa was in the class:
scyphozoa
the function of the siphonoglyph is
to form water currents into the gastrovascular cavity
sea anemones and corals lack:
a medusa stage
an organism with two cells layers separated by a mesoglea containing loosely packed cells, that was motile, and by all appearances moved like an amoeba, would be classified as:
placozoa
define typological species concept
has one organism as “ideal body” for that species
define biological species concept
based on reproductive properties of populations
define phylogenetic species concept
based on common descent
which process preformation or epigenesis, does our modern understanding of development conform to?
epigenesis
what is the fate of the blastopore in a fully developed animal?
develops into the mouth or anus
what is parsimony?
clagodram requiring fewest evolutionary steps/changes
difference between a sponge and colonial protozoan?
sponge is multicellular while protozoans are unicellular
about 95% of sponge species belong to the class ______
demospongiae
difference between syconoid and asconoid sponge body plan?
syconoid body plan is more complex than asconoid. The spongocoel has folded in syconoid body plan which increases surface area
how does velarium increase swimming speed of cubozoans?
it increases water pressure exiting the bell for faster movement
why don’t scyphozoans posses velum or velarium?
they have thick mesoglea and stronger coronal muscles
how are anemones different from other hexacorallians?
anemones lack an exoskeleton
