What is the life cycle of Obelia?

Through its life cycle, Obelia take two forms: polyp and medusa. They are diploblastic, with two true tissue layers—an epidermis (ectodermis) and a gastrodermis (endodermis)—with a jelly-like mesoglea filling the area between the two true tissue layers. They carry a nerve net with no brain or ganglia.

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 characteristics of Hydrozoa?

Hydrozoa consist of several marine organisms existinting in all three layers of the marine habitat. Some Hydrozoans live on the the surface(velella and Physalia) floating with large sail like structures above water for locomotion and long tentacles with nematocytes or stinging cells below the surface to catch food.

What is Medusa of Obelia?

A fully grown Obelia medusa is a radially symmetrical tiny umbrella, measuring 1 or 2 mm in diameter. Medusa is carnivorous and feeds on planktons.

What is polyp and medusa?

There are two basic cnidarian body shapes: a polyp form, which is attached to a surface; and an upside-down free-floating form called a medusa. Some cnidarians change form at different phases of their life cycle, while others remain in one form for their entire life.

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.

What is the order of Hydrozoa?

Hydrozoans are related to jellyfish and corals and belong to the phylum Cnidaria….Hydrozoa.

Hydrozoa Temporal range:
Subphylum:	Medusozoa
Class:	Hydrozoa Owen, 1743
Subclasses and orders
Hydroidolina Anthoathecata Leptothecata Siphonophorae Trachylinae Actinulida Limnomedusae Narcomedusae Tatalidoae

Does obelia have Ocelli?

There are eight spherical statocysts spaced evenly around the margin of the bell. Each is at the base of a tentacle. The statocysts are hollow, thin-walled, epidermal vesicles containing a calcareous statolith and a ciliated sensory epithelium. There are no ocelli in Obelia or other Leptothecatae.

What does the medusa stage of Obelia do?

Reproduction: Medusa Stage Medusa are jellyfish bearing the characteristic bell shape and tentacles. At this stage, the Obelia medusa swim freely and reproduce sexually by releasing either eggs or sperm into the water.

What is the medusa stage?

Medusa is a mobile life cycle stage of the species belonging to the Cnidaria phylum. Species of the Hydrozoa class exist in medusa form or jellyfish. Morphologically, a medusa is formed by a bell capable of muscular contractions which enables the medusa to swim.

What is polip?

A polyp is a projecting growth of tissue from a surface in the body, usually a mucous membrane. Polyps can develop in the: colon and rectum. ear canal. cervix.

What is polyp phase?

Polyp: Polyp is a sessile life cycle stage of species who belong to phylum cnidaria. Famous examples of polyp are sea anemones and adult corals. Polyp is formed with a mouth surrounded with tentacles, referred to as a head and head is attached to the bottom with a foot-like disk.