Lab 3 - Cnidaria and Ctenephora Flashcards
what specialized cells i cnidarians aid in capturing and subduing prey?
cnidocyte
How many embryonic layers does Cnidaria and Ctenophora have? What are they called?
two; endoderm and ecto derm
What is the term for a body that is derived from only two embryonic layers?
diploblastic
What is structure A? What is it for?
hydranth/gastrozooid
- it is used for feeding
What is structure B? What is it for?
gonangium/gonozooid
- it is for reproduction
What is F?
tentacles
what are E and A?
speta (septum singular)
what is B?
pedal disc
what is D?
pharynx
what modification do sea anemones possess to increase their digestive surface area?
septa
What tissue layer are cnidocytes located?
epidermis; because they are used for defense and prey capture
What is the organelle inside the cnidocyte called?
nematocyst
What causes the release of a nematocyst?
a trigger is stimulated, causing an increase in osmotic pressure within the cell, discharging the organelle
Do Hydra reproduce sexually or asexually?
both; through budding and fertilization
Obelia is solitary/colonial?
colonial
Hydra is solitary/colonial?
solitary
What characteristics can help you distinguish between hydrozoan and scyphozoan medusae?
Hydrozoan medusae generally have a muscular shelf, or velum, projecting inward from the margin of the bell
- velum is not found in scyphozoans
What is the structural equivalent of the chambers of a leuconoid sponge in Scyphozoa?
a branched gastrovascular cavity
What characteristics differentiate fire corals from true corals in class Anthozoa?
Fire corals are hydrozoans that have cnidocytes visible to the naked eye, whereas the cnidocytes of anthozoan corals are not visible to the naked eye
what characteristic of corals (anthozoans) is also found in Porifera?
filter feeding
What are some similarities between Cnidarians and Ctenophores? (5)
both are marine, diploblastic, with mesoglea, radial symmetry, and a branching GVC
what are some differences between Cnidarians and Ctenephores?
- Ctenophores have colloblasts instead of cnidocytes
- Cten. have eight “comb rows” of fused cilia
- many Cnidarians are mostly sessile
If the phylogeny shown here is correct, what is the implication for the evolution of the diploblastic body in animals?
The diploblastic body evolved independently in Ctenophores and Cnidarians
What specialized cells in Cnidarians aid in capturing and subduing prey?
cnidocytes
What structure(s) would help you determine whether a polyp of Obelia is a hydranth (feeding polyp) or a gonangium (reproductive polyp)?
tentacles; hydranths have them while gonangia do not
How many embryonic layers does this organism have? What are they?
two; endoderm and ectoderm
What phylum does this belong to? What is the specimen?
Ctenophore - “comb jelly”
What specimen is the following?
Phylum Cnidaria, Class Anthozoa, “sea pansy”
What are the following specimen?
Phylum Cnidaria, Class Anthozoa, aka stony corals
What is the following specimen?
Phylum Cnidaria, Class Anthozoa, organ pipe coral
What is the following specimen?
Aurelia- Phylum Cnidaria, Class Scyphozoa
What is the following specimen?
Phylum Cnidaria, Class Scyphozoa, cannonball jellyfish
What is the following specimen?
portuguese man-of-war, colonial; Phylum Cnidaria, Class Hydrozoa
What is the following specimen?
Phylum Cnidaria, Class Hydrozoa
Label A-C
A: transverse plane
B: sagittal plane
C: frontal plane
Label D-F
D: dorsal
E: ventral
F: anterior
Label G-I
G: posterior
H: proximal
I: distal
Label J and K
J: medial
K: lateral
dimorphic
displays two different body forms
medusa body form (3)
it is mobile, planktonic, and pelagic
planktonic
in the water column with movements subject to ocean currents
pelagic
living in the open ocean
medusa: oral surface
the side of the body contains the mouth/anus
medusa: aboral surface
the surface opposite to the mouth
What form is dominant in Class Hydrozoa?
the polyp but many have a medusa at some point
Hydrozoan medusae are unique in that…
they have very little mesoglea between their tissue layers
Hydra (Class Hydrozoa) is odd because… (2)
- lives in freshwater
- has no medusae
polymorphic
at least two body types
hydranth/gastrozooid
polyps with tentacles and have a feeding function
gonozooids/gonangia
polys with the function of asexual reproduction
the Portuguese Man-Of-War is a…
polymorphic colony of many individual polyps modified for various functions
what class of Cnidarians do we generally think of as ‘jellyfish’?
Class Scyphozoa
Class Scyphozoa medusae have more…
mesoglea, giving a plumper appearance
Class Scyphozoa life cycle
- male and female medusae reproduce asexually through gametes
- the zygote develops into a planula larva (free-swimming)
- planula larva settles onto a substrate and develops into a scyphistoma
- the scyphistoma polyp develops into a strobila, which asexually reproduces ephyrae
scyphistoma
a Scyphozoan polyp that develops after a planula larva
strobila
a Scyphozoan poly that asexually reproduces “stacks” of mini meducase known as ephyrae
ephyrae
mini juvenile medusae
A
What Classes can be found within Phylum Cnidaria? (4)
Classes
- Cubozoa
- Hydrozoa
- Scyphozoa
- Anthozoa
How many tentacles does Class Cubozoa have?
four, one for each ‘corner’
What class has medusae that are relatively quick swimmers and are active hunters?
Class Cubozoa
what class of Cnidarians has fairly well-developed vision?
Class Cubozoa
Where can you find members of Class Cubozoa?
widespread in warm oceans
Where can you find members of class Anthozoa?
exclusively marine
What body formes does Class Anthozoa exhibit?
only polyp
Are members of Class Anthozoa solitary or colonial? (3)
- solitary polyps
- colony of similar looking polyps
- colony of polymorphic polyps
D, B, A, C
Which Phylum is also called the ‘comb jellies’?
Ctenophora
What does Phylum Ctenophora use for movement?
eight rows of cilia called ctenes
What do members of Phylum Ctenophora use to capture prey?
colloblast cells
colloblast cells
secrete a sticky mucus to trap food in members of Ctenophora
What kind of nervous system do Phylum Cnidaria and Ctenophora use?
nerve net
Class Hydrozoa: forms
polyp is dominant but possess a medusa at some point
Class Scyphozoa: forms
medusa is dominant but possess a poly at some point
Class Cubozoa: forms
medusa is dominant bus possess a poly at some point
Class Anthozoa: forms
polyp only
Label this figure of a Scyphozoan life cycle.
A: planula
B: scyphistoma
C: stobila
D: ephyra
