Animal Kingdom

Paramecium: Classification, Characteristics, and  Morphology

Ciliates are distinguished by the existence of cilia on the body, two types of nuclei, one vegetative and the other reproductive, and conjugation, a unique form of sexual reproduction. About ten species of Paramecium exist, each with its shape, size, and structure. The majority of ciliates have complicated behaviour and advanced cellular organelles. Paramecium is found in freshwater, the sea, ponds, ditches, and streams, among other places, and is particularly prevalent in waterways containing decomposing organic materials. P. caudatum, P. aurelia, and P. bursaria are the most prevalent species.

Hydra: Classification, Occurrence, External Morphology, Budding, and Regeneration

Question: Explain the process of Regeneration in Hydra?
ANS: The ability of the hydra to regenerate lost body parts is one of its most interesting characteristics. When a hydra polyp is divided into two pieces, the headpiece regenerates the missing foot, while the foot regenerates the lost head. In hydra, this process does not necessitate growth (an increase in cell counts), at least in the early stages; it is hence called’morphallaxis,’ as a contrast to epimorphosis, which occurs in amphibian limb and tail regeneration and necessitates growth. As a result, the regenerated polyp is smaller than the original. Except for the tentacles and the basal disc, almost every portion of the hydra’s body is capable of regeneration to some degree.
A hydra cell pellet can regenerate into a polyp. When a hydra is cut into three pieces, the central portion, which is missing both the head and the foot, regenerates a new head and foot on the sides where the original head and foot were. This implies that information exists in the cells of the centre component that directs the regeneration of lost portions in the original orientation.