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