hydrostatic movement in hydra
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Locomotion of Hydra:
Normally, aHydra remains attached by the basal disc to some suitable object in the water. There it twists about and makes various movements of the tentacles and body in response to various stimuli and for the capture of food.
Normally, a Hydra remains attached by the basal disc to some suitable object in the water. There it twists about and makes various movements of the tentacles and body in response to various stimuli and for the capture of food. All such movements are caused by the contraction or expansion of the contractile muscle fibres of the muscle processes of both epidermis and gastro dermis.
Actual locomotion is accomplished in several different ways which are as follows:
(i) Looping:
The most common, a type of walking (Fig. 31.15) similar to the looping of an inchworm or caterpillar. While standing erect, the body first extends and then bends and fixes the tentacles to the substratum by means of glutinant nematocysts. It then releases the attachment of the basal disc, reattaches the basal disc near the tentacles and again assuming an upright position by releasing its tentacles.
(ii) Somersaulting:
Somersaulting (Fig. 31.16) is like the looping. In this type of movement, Hydra extends its body and is bent to one side to place the tentacles on the substratum, the glutinant nematocysts help to fix the tentacles. The basal disc is freed from its attachment, and the animal stands on its tentacles, the body then contracts strongly till it appears like a small knob.
The body is then extended and bent to place the basal disc on the substratum, the tentacles loosen their hold and the animal regains an upright position. These movements are repeated and the Hydra moves from place to place. This is the normal method of locomotion.
(iii) Gliding:
Hydra can glide slowly along its attachment by alternate contraction and expansion of basal disc.
(iv) Cuttlefish-like movement:
The tentacles are fixed to the substratum and with the pedal disc up, Hydra moves over the substratum by pulling its tentacles along.
(v) Floating:
Sometimes, Hydra can produce a bubble of gas secreted by some ectodermal cells of the basal disc which helps the animal to float on the surface of the water and is passively carried from one place to another by water current or wind below.
(vi) Climbing:
Hydra can climb by attaching its tentacles to some distant objects and then releasing the basal disc and by contracting the tentacles the body is drawn up to a new position.
(vii) Swimming:
By freeing itself from the substratum and with the help of wave-like movements of the tentacles, Hydra swims in water.
Normally, aHydra remains attached by the basal disc to some suitable object in the water. There it twists about and makes various movements of the tentacles and body in response to various stimuli and for the capture of food.
Normally, a Hydra remains attached by the basal disc to some suitable object in the water. There it twists about and makes various movements of the tentacles and body in response to various stimuli and for the capture of food. All such movements are caused by the contraction or expansion of the contractile muscle fibres of the muscle processes of both epidermis and gastro dermis.
Actual locomotion is accomplished in several different ways which are as follows:
(i) Looping:
The most common, a type of walking (Fig. 31.15) similar to the looping of an inchworm or caterpillar. While standing erect, the body first extends and then bends and fixes the tentacles to the substratum by means of glutinant nematocysts. It then releases the attachment of the basal disc, reattaches the basal disc near the tentacles and again assuming an upright position by releasing its tentacles.
(ii) Somersaulting:
Somersaulting (Fig. 31.16) is like the looping. In this type of movement, Hydra extends its body and is bent to one side to place the tentacles on the substratum, the glutinant nematocysts help to fix the tentacles. The basal disc is freed from its attachment, and the animal stands on its tentacles, the body then contracts strongly till it appears like a small knob.
The body is then extended and bent to place the basal disc on the substratum, the tentacles loosen their hold and the animal regains an upright position. These movements are repeated and the Hydra moves from place to place. This is the normal method of locomotion.
(iii) Gliding:
Hydra can glide slowly along its attachment by alternate contraction and expansion of basal disc.
(iv) Cuttlefish-like movement:
The tentacles are fixed to the substratum and with the pedal disc up, Hydra moves over the substratum by pulling its tentacles along.
(v) Floating:
Sometimes, Hydra can produce a bubble of gas secreted by some ectodermal cells of the basal disc which helps the animal to float on the surface of the water and is passively carried from one place to another by water current or wind below.
(vi) Climbing:
Hydra can climb by attaching its tentacles to some distant objects and then releasing the basal disc and by contracting the tentacles the body is drawn up to a new position.
(vii) Swimming:
By freeing itself from the substratum and with the help of wave-like movements of the tentacles, Hydra swims in water.
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Hydra is a unicellular eukaryotic organism. It can be found in the freshwater.
Explanation:
- The hydra shows movement from one substrate to another by the gliding movement along the basal disc or by the somersaulting.
- When the hydra performs somersaulting then they detach their basal disc of the body from the substrate and bend forward and place the tentacles down towards the substrate. This is followed by the attachment of the basal disc again to the substrate.
Learn more about Hydra:
What is hydra ?what is the function of hydra?: https://brainly.in/question/779212
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