how does hydra reproduce

 
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Figure 13.3 (a) Hydra reproduce asexually through budding: a bud forms on the tubular body of an adult hydra, develops a mouth and tentacles, and then detaches from its parent. leads to -such fission. A bud is usually formed in the middle of the body by rapid multiplication of inter­stitial cells. Explain with the help of labeled diagrams. Before sharing your knowledge on this site, please read the following pages:

The discharged thread pierces the animal body and the fluid hypo-toxin, protein in nature, in the nemato­cyst, has a numbing effect on the animals. Sexual reproduction usually occurs in winter and spring months. The erect body extends and bends, the tentacles are attached to the substratum forming a loop. 1 Answer +1 vote . Hypostome is a small, elevated cone surrounded by the tentacles. The zygote cleaves immediately.

The hydra glides over the substratum with the amoeboid movement of the cells of the basal disc, without any... B.

The processes are joined directly to the sensory cells and to the muscular processes of the epitheliomuscular cells. Small bits of food which escape digestion in the coelenteron are engulfed by the amoeboid endodermal cells and digested within food vacuoles in typical amoeboid fashion. The exchange of oxy­gen and carbon dioxide gases—necessary for respiration and excretion of nitrogenous wastes (chiefly ammonia) occurs directly by diffusion through the cell membranes as in protozoans. The wall of the body, tentacles and buds are made up of two layers of cells (Fig. Oval, about 9 µm. The germ cells, when formed, are meant for reproduction. 61). The new cells migrate into and fill up the cavity of the blastula which in this manner, is converted into two layers of cell. The bodies of fully developed individuals consist of a thin, usually translucent … a. The penetrant type is used for offence and defence as well as for capturing and paralyzing the prey. It is the oocyte. 7. 1. 55 C). Brien (1953) and others found that in hydra there is a growth zone just below the base of the tentacles. c. A delicate protoplasmic process, the cnidocil or trigger hair at the anterior end, projecting beyond the surface. 4. The mouth is round and situated at the centre of the hypostome. Sexual reproduction also occurs. e. The ectodermal cells secrete a two lay­ered protective shell called cyst or theca around gastrula.

6. Such a group or battery of nematocysts usually consists of one or two of the large penetrant type in the centre surrounded by several of the other two kinds. 1. 20.3F). The protective cuticle is absent from the basal disc and the epitheliomuscular cells are replaced here by narrow and tall gland cells which secrete a sticky material for fixing the animal firmly to its substratum. The extensions take a circular course next to mesogloea.

It either sinks in the mud at the bottom or sticks to aquatic plants. 4. Welcome to NotesOnZoology.com! All the cells may be renewed within 45 days. In higher metazoa, the body cells are highly specialised and such undifferentiated cells are usually absent. One centrally located cell, the oocyte, becomes larger and amoeboid with a large nucleus and yolk materials. Hydra is the simplest fresh water metazoa. These buds develop into tiny individuals and when fully mature, detach from the parent body and become new independent individuals. Between the two cellular layers, there is a thin non-cellular mesogloea of jelly-like consis­tency. These are therefore used for immobilizing and capturing food. Cnidocytes once used become non-func­tional and cast off. in size; thread long with three or four transverse coils and bears small nettles (Fig. 1.

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