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 animals belong to Hydrozoa?
Hydrozoa is a class within the phylum Cnidaria, which includes sea anemones, corals, and jellyfish. The vast majority are marine species, but freshwater hydrozoans are known, for example, Cordylophora lacustris and Craspedacusta sowerbyi.
What are the characteristics of Hydrozoa?
Class Hydrozoa
- Internal space for digestion is the gastrovascular cavity.
- Gastrovascular cavity has one opening, the mouth.
- Exoskeleton of chitin.
- Are almoust entirely marine and predators.
- Sexual reproduction produces the planula larvae.
- Two body forms, a polyp and medusea.
- Presence of stinging cells called Cnidocytes.
What is an example of bilateral symmetry?
Examples of animals that possess bilateral symmetry are: flatworms, common worms (“ribbon worms”), clams, snails, octopuses, crustaceans, insects, spiders, brachiopods, sea stars, sea urchins, and vertebrates. The symmetry of an animal generally fits its lifestyle.
What makes a Hydrozoa a Hydrozoa?
The Hydrozoa is a subgroup of cnidarians containging approximately 3700 species. It is a diverse group with a variety of life cycles, growth forms, and specialized structures. Like many cnidarians, hydrozoans have both polyp and medusa stages in their life cycle.
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 is polymorphism Hydrozoa?
The occurrence of more than one type of structurally and functionally different individuals within a population is called polymorphism. The class Hydrozoa of phylum Coelenterata includes a large number of colonial species that contain more than one form of individuals which are called zooids.
Does Hydrozoa have velum?
Free-living medusoid hydrozoans can be hard to tell from scyphozoans, but hydrozoan medusae generally have a muscular shelf, or velum, projecting inward from the margin of the bell.
What is the life cycle of Hydrozoa?
The basic life cycle of hydrozoans comprises a succession of developmental stages: planula larva, hydroid and dioecious hydromedusa [2]. Sessile polyps produce medusae through asexual budding. A medusa is a mobile reproductive stage. After fertilisation a planula larva develops.
What are some differences between Scyphozoans and Cubozoans?
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.
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.
Why is Hydra in Hydrozoa?
All Hydra species feed on other small invertebrate animals such as crustaceans. Hydra is an unusual hydrozoan genus in that its life cycle lacks any trace of a jellyfish stage, and the polyp stage is solitary rather than colonial.
Why do hydrozoans have different structures?
Most colonial hydrozoans are polymorphic, with different structures reflecting different functions. Some are armed with large spines tentacles for defense but have no mouth, some have tentacles and functional mouths for feeding, and some are only reproductive, with no tentacles or mouth, and produce medusae (see below) or gametes.
What is the difference between Hydrozoa and Anthozoa?
The hydrozoans contain sessile forms and swimming colonial forms like the Portuguese Man O’ War. The class Anthozoa includes all cnidarians that exhibit a polyp body plan only; in other words, there is no medusa stage within their life cycle.
What is an example of body symmetry in animals?
a form of body symmetry in which the parts of an animal are arranged concentrically around a central oral/aboral axis and more than one imaginary plane through this axis results in halves that are mirror-images of each other. Examples are cnidarians (Phylum Cnidaria, jellyfish, anemones, and corals).
Do hydrozoans have cnidocytes?
Like all cnidarians, hydrozoans have special ectodermal cells called cnidocytes, each containing a single intracellular structure called a cnida (aka nematocyst). Cnidae are unique to the Cnidaria.