Kingdom – Animalia
Subkingdom – Eumetazoa
Phylum – Cnidaria
Subphylum – Medusozoa
Class – Hydrozoa
Subclass – Leptolinae
Order – Anthomedusae
Suborder – Capitata
Family – Hydridae
Genus – Hydra Linnaeus
Motion and locomotion of Hydra
Whenever Hydra are startled or attacked, they retract their tentacles to form small buds. They can as well retract their entire body column into a small gelatinous sphere. Hydra usually reacts in the same manner irrespective of the direction of the stimulus, and this might be as a result of the simplicity of the nerve net.
The sessile or sedentary behavior of Hydra
Hydra is usually sedentary or sessile but can on occasional basis transport itself swiftly particularly when hunting for food. They normally do this by bending over and fastening themselves to the substrate with the mouth and tentacles and after that let go of their feet, which makes available the typical attachment.
This process in hydra is referred to as looping. The body subsequently bends over and makes a fresh position of attachment with the foot.
Through this process of “looping” or “somersaulting”, a Hydra can be in motion quite a lot of inches (c. 100 mm) on a daily basis. Hydra may also move about through amoeboid movement of their bases or by merely coming off the substrate and hovering away through the water current.
Reproduction and life cycle of Hydra
When there is a lot of food, are plentiful, loads of Hydra reproduce asexually by generating buds in the body wall. These buds grow to be small adults and merely breaking away when they are full-grown.
When conditions are unsympathetic, habitually before winter or in poor feeding and nutritional situations, some Hydra undergo sexual reproduction. Inflammations in the body wall expand into either a straightforward ovary testes.
The testes discharge free-swimming gametes into the water, and these possibly may fertilize the egg in the ovary of another individual hydra.
The fertilized eggs ooze a hard outer coating, and, as the fully developed hydra dies, these dormant eggs get discharged to the bottom of the lake or pond to wait for favorable conditions, at which point they hatch into nymph Hydra. Some type of Hydra like Hydra circumcincta and Hydra viridissima, are hermaphrodites and may at the same time bring into being both testes and an ovary.
Various members of the Hydrozoa pass through a body alteration from a polyp to an adult form known as a medusa. Nevertheless, all Hydra, regardless of being hydrozoans, hang about as polyps all the way through their lives.
Feeding of Hydra
The feeding in Hydra is majorly on minute aquatic invertebrates like as Daphnia and Cyclops.
When feeding, Hydra extends their body to their highest length and after that little by little extends their tentacles. In spite of their plain construction, the tentacles of Hydra are amazingly extensible and can be extended up to four to five times the length of the entire body.
Just immediately they are completely extended, the tentacles are bit by bit maneuvered more or less waiting to make contact with an appropriate prey animal. Once they come in contact, nematocysts on the tentacle shoot into the prey, and the tentacle then coils over the prey.
Just within a space of 30 seconds, the majority of the rest tentacles would have already united in the attack to suppress and hold back the besieged prey. Just about two minutes, the tentacles will have bordered the prey and stirred it into the opened mouth opening.
In a space of about ten minutes, the prey will have been completely engulfed into the body cavity, and digestion will have been on track. Hydra is able to elongate its body wall by a long way in order to digest prey that is two times its size.
After two or three days, the hard to digest parts of the prey will be released through the contractions of the aperture in the mouth.
The feeding attitude of Hydra illustrates the cleverness of what seem to be just a mere nervous system.
A few species of Hydra occur in a joint relationship with a combination of types of unicellular algae. The algae are sheltered from predators by Hydra and, in return, photosynthetic products from the algae are valuable as a source of food to Hydra.