How do you tell if a medusa is an scyphozoa vs hydrozoa?
How do you tell if a medusa is an scyphozoa vs hydrozoa?
Differences between a Scyphozoan & Hydrozoan medusae? Schyphozoans – More ‘jelly & 4 oral arms. Hydrozoans – No oral arms. Have a velum ring & less jelly (fold up when preserved).
What is difference between polyp and medusa?
Sessile structures are called polyps while the swimming forms are called medusa. The key difference between polyp and medusa is that polyp is a fixed, cylindrical structure, representing the asexual stage and medusa is a free swimming, umbrella-like structure, representing the sexual stage.
Is scyphozoa a medusa or polyp?
Most species of Scyphozoa have two life-history phases, including the planktonic medusa or jellyfish form, which is most evident in the warm summer months, and an inconspicuous, but longer-lived, bottom-dwelling polyp, which seasonally gives rise to new medusae.
What animals belong to scyphozoa?
The class Scyphozoa can be found in the phylum of Cnidaria, the phylum of the “stinging” creatures, such as jellyfish. There are approximately 200 species that belong to the class Scyphozoa, and they are the most familiar of the gelatinous creatures of our world. These include, sea nettles, moon jellies and jellyfish.
What animals belong to hydrozoa?
Some examples of hydrozoans are the freshwater jelly (Craspedacusta sowerbyi), freshwater polyps (Hydra), Obelia, Portuguese man o’ war (Physalia physalis), chondrophores (Porpitidae), “air fern” (Sertularia argentea), and pink-hearted hydroids (Tubularia).
Where are hydrozoa found?
Most Hydrozoans live in saltwater but some species, like Hydra, are found in freshwater. Most hydrozoans have both a polyp stage and a medusa stage in their life cycles. Most are found as small colonies made up from tiny polyps connected together by hollow stems (called hydrocauli).
What are examples of scyphozoa?
Rhizostomae
SemaeostomeaeCrown jellyfishCoronamedusaeMawsonites
True jellyfishes/Lower classifications
What is Cnidocytes and its function?
Cnidocytes (‘stinging cells’) are specialized cells that define the phylum Cnidaria (sea anemones, jellyfish, corals and hydras). They contain an “explosive” organelle called cnidocyst that acts as a 600 million-years-old microscopic injection system and is important for prey capture and anti-predator defense.
What is scyphozoa scientific name?
Scyphozoa
True jellyfishes/Scientific names
What makes a hydrozoa a hydrozoa?
Hydrozoa consist of several marine organisms existinting in all three layers of the marine habitat. These Hydrozoans are the orders Milleporina and Stylasterina which are corals and form an internal, epidermal skeleton of calcareous. These organisms can grow very large covering mass amounts of ocean substrate.
How does a scyphozoan Medusa differ from a hydrozoan?
Scyphozoan medusae differ from those of hydrozoans in lacking a velum. A scyphomedusa locomotes by contracting and relaxing muscles of the bell. Contraction pushes water out, propelling the jelly in jet-like fashion.
Can a hydrozoan form a polyp or medusa stage?
In scyphozoans, the medusa stage is typically large and free-living, with the polyp stage small. However, there are exceptions — certain hydrozoans known as the Trachylina never form a polyp stage.
What kind of cycle does a Hydrozoa have?
Most hydrozoans show the same alternation between polyp and medusa phases that the Scyphozoa, or “true” jellyfish, have. A fertilized egg develops into a sessile polyp, which buds asexually and eventually buds off one or more medusae. The medusa produce eggs and sperm, reproduce sexually, and thus the cycle is repeated.
How does a scyphistoma turn into a medusa?
Eventually, a scyphistoma becomes a strobila, in which the distal end develops into a medusa-like animal. The strobila may look like a stack of saucers, the saucers being the immature medusae called ephyrae. As formation of the ephyrae is completed, each breaks away and eventually grows into a sexually-reproducing adult medusa.
