Question

Name the organ that helps in nutrition in hydra.

Answer 1

Hint: Hydra is basically the freshwater living organisms and they are very small in size. Hydra is considered under the phylum Cnidaria. They are one of the most simple organisms in terms of body structure. Hydra is well known to be biologically immortal. This is because they do not undergo any senescence and also have a very high regeneration capacity.

Complete answer:
 The body of hydra is mainly differentiated into a very long trunk and the mouth is also surrounded by the tentacles. Body cavity is also present and the body wall is diploblastic in nature. In hydra, holozoic mode of nutrition takes place. Holozoic nutrition is the mode of nutrition that involves ingestion of food which is either solid or liquid. Hydra are also heterotrophic in nature, this means that they cannot produce their own food.

The tentacles which are present around the mouth help the hydra in the ingestion of food. The tentacles are very long and they have the ability to catch the small aquatic organisms. Once these organisms are captured, they kill these small aquatic organisms using their stinging cells which are present in the tentacle. The prey is then gradually pushed into the mouth and once it reaches the body cavity, various kinds of digestive juices help in digestion of the food. After digestion of food has taken place, it is absorbed through the walls of the cavity and assimilated in the cells.

Thus, the tentacle of the hydra is the organ that helps in nutrition in hydra.

Note: Omnivorous animals are those animals which feed on animals as well as plants. Humans fall under this category but hydra is carnivorous. Hydra is made up of the stinging cells called nematocysts on their tentacles. The tentacles are used to tangle up the prey and stinging cells then release toxins that paralyse the prey.