Quiz #2 - Ctenophores and Cnidarians
Ectoderm = Endoderm =
Epidermis, Gastrodermis
The Physalia physalis is
Portuguese man-of-war - with polymorphic colony
Compare and Contrast the schyphozoan medusa with the medusa bud of obelia.
Compare: scyphozoan are larger in size with more numbers of tentacles - they also have oral arms. Contrast: both are radially symmetrical, tentacles surround the mouth
Which of the following is a characteristic of corals (anthozoans) that are also found in Porifera?
Filter Feeding
If the phylogeny shown here is correct, what is the implication for the evolution of the diploblastic body (tissue level of organization) in animals?
The diploblastic body is evolved independently of Ctenophores and Cnidarians. An Ancestor of the Porifera had a more complex body that was then lost.
How is a nematocyst discharged?
When a small trigger on a cnidocyte is stimulated, there is an increase in osmotic pressure that causes the nematocyst to rupture extending out a long hollow filament.
Radial Symmetry is
arrangement around a central axis
Tentacles are
extensions around the mouth used for prey and defense
Myxozoa is
microparasites
Pedal Disc is
tough, fleshy base for attachment
What are the 4 Classes of Cnidaria?
Hydrozoa, Cubozoa, Scyphozoa, Anthozoa
Bilateral Symmetry is
division of body parts into two
In Class Hydrozoa
polyp is the dominant stage (colonial), produce a medusastage with a velum ring and no oral arms (not genus), the very little mesoglea, display sexual and assexual stage
Ostium is
pore that permits the circulation of fluid between chambers
Class Scyphozoa (true sea jelly)
thick layer of mesoglea, with a medusa is the dominant life stage, largest is lion's mane
Name 2 things to distinguish a hydrozoan and scyphozoan medusae?
1 - Hydrozoa medusae are small or absent/Scyphozoan the medusae is large and free living. 2 - Hydrozoa medusae have a velum that projects inwards/Scyphozoan do not. 3 - Hydrozoa medusae lack cells in the mesoglea/Scyphozoan contain ameoboid cells there.
How does Hydra reproduce?
BOTH // Sexually through the production of eggs and sperm // Assexually through budding.
Ctenophora Characteristics
Diploblastic, radial symmetry, hydrostatic skeleton, collenchyme (similar to mesoglea), 8 rows of cilia, colloblast cells, lack cnidocytes, nerve net, incomplete gut, ECR - diffusion, no assexual reproduction (monoecious)
Obelia have specialized polyps: Hydranths? Gonangium? Freshwater or Saltwater?
Hydranths - feeding polyps Gonangium - assexually reproducing polyps // freshwater
Characteristics of a Phylym Cnidaria
Radial Symmetry, Tissue Level Organiztion, Diploblastic, Hydrostatic Skeleton, Lacks nervous tissue and sensory organs (has nerve net and ocelli), Incomplete Cut (extracellular and intracellular digestion), Cnidocytes, Diffusion in (Excretion, Circulation, Respiration)
What are some Similatries and Differences between the Cnidaria and Ctenophora?
SIM - marine, diplobastic, radial symmetry, mesoglea, branching GVC DIF - Ctenophores have colloblasts/Cnidarians have cnidocytes. Ctenophores have 8 rows of cilia, Cnidarians do not./ Cnidarians are pretty much sessile.
What is the reproduction of a Cnidaria?
Sexual (monoecious and dioecious) and Assexual (budding, fission, fragmentation, pedal laceration)
Where are Cnidocytes located? Why?
They are located in the epidermis because they are used for prey and capture, thus they must be located in the outermost tissue layer.
What is the structural equivalent of the chambers of a leuconoid sponge in the Scyphozoa?
a branched gastrovascular cavity
colloblast -
cells that adhere to prey and bring to mouth
Obelia occcurs as a ______ polyp whereas Hydra occurs as a _____ polyp. Obelia has ______ polyps, Hydra does not. ______ is more sessile.
colonial, solitary, reproductive, Obelia
Ctenophora are
comb jellies
Which of these is a characteristic that differentiates fire corals and true corals?
fire corals are hydrozoans that have cnidoccytes relatively visable to the naked eye, where the cnidocytes of anthozoan corals are not visible to the naked eye
Asymmetry is
irregular arrangement
Class Anthozoa
is sessile with only a polyp stage (no medusa), solitary individuals, most specialized, all marine
Class Cubozoa
is with a cube shaped dominant medusae stage, 4 evenly spaced out tentacles
Polypodiozoa is
microparasites
Cnidocytes contain a stinging capsule called a ______ that penetrates, coils, and adheres by releasing toxins. Where do they live?
nematocyst, epidermis
The Mesoglea is
not a tissue layer, but a jelly like substancce that provides support for the body
Class Hydrozoa is
not true corals (hydrocorals) with a calcified skeleton that is sharp and can scrape skin
Staurozoa is
stalked jellyfish
Primary Septum is
thin, vertical wall that divides the body and provides an increase in SA for digestion