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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.
- How do you identify hydrozoa?
- What are some characteristics of cnidarians that belong to the class Hydrozoa?
- What does a hydrozoa look like?
- Is a hydrozoa a medusa or polyp?
- What makes hydrozoa unique?
- What are two characteristics of the class scyphozoa?
- What are some differences between Scyphozoans and Cubozoans?
- What are typical characteristics of cnidarians?
- Where are hydrozoa found?
- Which of the following are characteristics of members of Class scyphozoa?
- What is polymorphism hydrozoa?
- Why is Hydra atypical of the class Hydrozoa?
- Are hydrozoa sessile?
How do you identify hydrozoa?
Marine identification key: Hydrozoa. The Hydrozoa is a class of Cnidaria. They are characterized by having a life-cycle involving sexual and asexual reproduction. Most hydrozoans have a benthic, colonial polyp stage, which reproduces asexually by budding.
What are some characteristics of cnidarians that belong to the class Hydrozoa?
Cnidarians are radially symmetrical (i.e., similar parts are arranged symmetrically around a central axis). They lack cephalization (concentration of sensory organs in a head), their bodies have two cell layers rather than the three of so-called higher animals, and the saclike coelenteron has one opening (the mouth).
What does a hydrozoa look like?
The body consists of a dome-like umbrella ringed by tentacles. A tube-like structure hangs down from the centre of the umbrella, and includes the mouth at its tip. Most hydrozoan medusae have just four tentacles, although a number of exceptions exist. Stinging cells are found on the tentacles and around the mouth.
Is a hydrozoa a medusa or polyp?
Hydrozoans generally display alternation of generations between polyp and medusa, although hydras exhibit only the polyp form and some species are represented only by medusae and lack the polyp stage. Hydrozoans are carnivorous animals that can be solitary or colonial.
What makes hydrozoa unique?
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. ... In many colonies, polyps are polymorphic, with different structures reflecting different functions.
What are two characteristics of the class scyphozoa?
Scyphozoans exhibit the main characteristics of cnidarians. They have radial symmetry and are diploblastic, meaning that their body wall consists of the outer epidermis (ectoderm) and the inner gastrodermis (endoderm), which are separated by mesoglea. They have nematocysts, which are characteristic of the phylum.
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 are typical characteristics of cnidarians?
All Cnidaria are aquatic, mostly marine, organisms. They all have tentacles with stinging cells called nematocysts that they use to capture food. Cnidarians only have two body layers, the ectoderm and endoderm, separated by a jelly-like layer called the mesoglea. Most Cnidarians have radial symmetry.
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).
Which of the following are characteristics of members of Class scyphozoa?
Which of the following are characteristics of class Scyphozoa? They move by jetting water from the gastrovascular cavity or space beneath it, using the rhythmic contraction of muscles and the medusa is the major body form, with the polyp being greatly reduced or even absent in some species.
What is polymorphism hydrozoa?
different individuals within a population is called polymorphism. It is one of the. characteristic features of coelenterate, 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.
Why is Hydra atypical of the class Hydrozoa?
A Hydra was first described by Leeuwenhoek in 1703. Unusual because in Hydra there is no medusa. ... So, although a common laboratory animal Hydra is an atypical hydrozoan, because it only has a polyp stage and lives in fresh water.
Are hydrozoa sessile?
Hydrozoa (phylum Coelenterata, class Hydrozoa) are coelenterates that are closely related to the hydra ,sea anemones , corals, and jellyfish . In addition, two main types of hydrozoa exist: a polypoid structure which is sessile, remaining in the same place, and a medusoid form which is free-swimming. ...
