How do Hydrozoa reproduce?

How do Hydrozoa reproduce?

Most hydrozoans have a benthic, colonial polyp stage, which reproduces asexually by budding. Many have free swimming, sexually reproducing medusae (see Introduction to Ctenophores (and Cnidarian medusae)). Others have attached gonophores, which will produce eggs or sperm.

Which one is a example of class 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).

What are characteristics of Hydrozoa?

Most hydrozoan species have a planktonic larval stage called a planula. Planulae are radially symmetric ovoids, often covered with flagellate cells for swimming. They may be very simple embryos or have cells differentiated into several types. Planulae most often settle onto a benthic substrate and develop into a polyp.

What are some differences between Scyphozoans and Cubozoans?

Key Points. Cubozoans differ from Scyphozoans in their arrangement of tentacles; they are also known for their box-shaped medusa. Out of all cnidarians, cubozoans are the most venomous. Hydrozoans are polymorphs, existing as solitary polyps, solitary medusae, or as colonies.

What is the life cycle of Hydrozoa?

In many hydrozoan species, the life cycle consists of a free-living planula larva that transforms into a primary polyp. The primary polyp buds other polyps to produce a benthic colonial stage. Upon reproductive maturity, the polyps bud pelagic medusae that ultimately form gametes and spawn in the water column.

What is the difference between Hydrozoa and scyphozoa?

The difference between most hydrozoans and most scyphozoans is that in hydrozoans, the polyp stage usually predominates, with the medusa small or sometimes absent. Often, the medusa never breaks away from the parent polyp, and remains in a state of arrested development, although its gametes function.

Where is 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 is the difference between hydrozoans and scyphozoans?

Hydrozoans have a sexual medusa stage and a nonsexual polyp stage, whereas scyphozoans have a shortened asexual polyp stage. Hydrozoans have velum at the medusa that aids in propulsion, but scyphozoan polyps lack this velum.

What is the common name for Hydrozoa?

hydralike animals
Integrated Taxonomic Information System – Report

Common Name(s): hydralike animals [English]
hydroids [English]
hydrozoans [English]
hydraires [French]
hydrozoaires [French]

What are called polyps?

Polyps, Colonies, and Reefs Coral polyps are tiny, soft-bodied organisms related to sea anemones and jellyfish. At their base is a hard, protective limestone skeleton called a calicle, which forms the structure of coral reefs.

Is Hydrozoa multicellular?

Hydrozoa (hydroids; phylum Cnidaria) A class of multicellular, mainly marine animals in which the cells are derived from two layers, epidermis and gastrodermis (endodermis), separated by a gelatinous mesogloea.

What is the difference between polyps and medusae?

Polyps have a tubular shape and are fastened at their base, with the mouth facing the water at the other end of the tube. Medusa has a bell-shaped body with hanging tentacles. Polyp does not have a manubrium. The Hydrozoa class’s Medusa has a manubrium, a tube that hangs from the bell.

Do hydrozoans reproduce asexually or sexually?

In some species, the reproductive polyps, known as gonozooids (or “gonotheca” in thecate hydrozoans) bud off asexually produced medusae. These tiny, new medusae (which are either male or female) mature and spawn, releasing gametes freely into the sea in most cases.

What are colonized Hydrozoa?

Colonial hydrozoans include siphonophore colonies, Hydractinia, Obelia, and many others. In hydrozoan species with both polyp and medusa generations, the medusa stage is the sexually reproductive phase. Medusae of these species of Hydrozoa are known as “hydromedusae”.

Do hydrozoans have a medusoid stage?

Although most hydrozoans have a medusoid stage, this is not always free-living, and in many species, exists solely as a sexually reproducing bud on the surface of the hydroid colony. Sometimes, these medusoid buds may be so degenerated as to entirely lack tentacles or mouths, essentially consisting of an isolated gonad.

What are the classification of hydrozoans?

In any case, according to this classification, the hydrozoans can be subdivided as follows, with taxon names emended to end in “-ae”: Order Anthoathecata (= Anthoathecata (e), Athecata (e), Anthomedusae, Stylasterina (e)) — includes Laingoimedusae but monophyly requires verification