What is the difference between a polyp and medusa body form?
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.
Are Hydrozoa medusae or polyps?
Like many cnidarians, hydrozoans have both polyp and medusa stages in their life cycle.
What important function does the medusa accomplish for the obelia?
The medusa, or jellyfish, swim freely and reproduce sexually, releasing eggs and sperm into the water. The resulting fertilized eggs develop into larvae, which attach to the ocean floor as new polyps.
What is a medusa stage?
The medusa is the reproductive stage; their eggs are fertilised internally and develop into free-swimming planula larvae. After a brief period floating about in surface waters, the larvae settle to the sea floor, attaching themselves at one end. There they develop into polyps and begin to feed and grow.
What does medusa body look like?
During this time, Medusa is depicted as a monster; she has a round face, wide eyes, a beard, and a gaping mouth with an extended tongue and gnashing, sharp teeth (39.11. 9). Medusa remains a popular image on later architectural components, but her form is more specifically human and female.
Does Cubozoa have a polyp stage?
Cubozoans have separate sexes and fertilization occurs inside the female. Planula larvae may develop inside the female or be released, depending on species. Each planula develops into a polyp. These polyps may bud to form more polyps to create a colony; each polyp then transforms into a single medusa.
Which of the following does not have a medusa stage?
Anthozoa
Anthozoa is a class within the phylum Coelenterata. Unlike other coelenterates, anthozoans do not have a medusa stage in their development.
How can you distinguish the medusae of Obelia and Gonionemus?
These are used to detect position. There are no ocelli in Obelia. Gonionemus is a shallow-water marine species of Hydrozoa. The medusa is about 2 cm in diameter and has a thick bell.
Where are medusae produced in Obelia?
The polyp asexually produces medusae, or jellyfish. Obelia medusae release sperm or eggs into the surrounding water, and the resulting ciliated larva eventually metamorphoses to produce a branching colony of polyps.
What is a manubrium in Cnidaria?
During feeding, the pedalium pushes the prey inside the bell of the medusa, the manubrium (which is the tube that connects the stomach on one end to the the four-parted mouth on the other) reaches out and finds the prey. The mouth then expands and engulfs the prey.
What are polyp and medusa stages?
Polyp is a sessile life cycle stage of the Cnidaria phylum. Medusa is a mobile life cycle stage of the Cnidaria phylum, contracting with it muscular bell. Polyp have a tubular shape and are fixed at their base, with the mouth present at the other end of the tube facing the water.
What is the 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.
Which of the following does not have medusa stage?
Unlike other coelenterates, anthozoans do not have a medusa stage in their development. Instead, they release sperm and eggs that form a planula, which attaches to some substrate on which the cnidarian grows.
Is a medusa free living?
Within the Cnidaria are free-living forms (the medusae or jellyfish) and fixed forms (polyps). Four classes are important for human medicine: Anthozoa (corals and anemones) (Fig.
Is Gonionemus polyp or medusa?
Statocysts, but not ocelli, are present and the gonads are on the radial canals. 1. Gonionemus Although polyps of the Limnomedusae are reduced and tiny, the medusae are larger than those of most hydrozoans and are easily studied.
What is the Obelia Medusa?
The below mentioned article provides a diagram of obelia medusa. 1. It is the slide of Obelia medusa which is a reproductive zooid responsible for giving rise to new progeny. 2. These are saucer-like or umbrella- shaped structures and are developed from blastostyles asexually.
What is the manubrium of Obelia?
From the surface of the subumbrellar surface emerges a hanging tube called manubrium bearing a square mouth at its terminal end (Fig. 1.37D). As the medusa of Obelia swims, the umbrella becomes turned inside out, the sub-umbrella then forming the convex surface and the manubrium arising from its apex.
How to identify Obelia geniculatamedusa?
Diameter up to 4 mm. How to Distinguish from Similar Species: TheObelia geniculatamedusa is about the same size and shape and has similar gonads, but the gonads are located closer to the mouth and move out to about halfway along the radial canalas the medusagrows. Geographical Range: Alaska to San Diego, and worldwide in temperate zones
Is Obelia a hydrozoan?
Obelia is a typical example of a marine, colonial hydrozoan. Like most hydrozoans it has both polyp and medusa stages. Obelia occurs as a delicate whitish or light brown, almost fur-like growth on seaweeds or timber.