Question

What are the 5 differences between Hydra and the rest of Hydrozoa?

Answer 1

Hydra is a small and fresh water organism which belongs to the phylum Cnidaria and the class of Hydrozoa. However, there are couple of differences that exists between Hydra and all other species of the Hydrazoa. They mostly grow in temperate as well as tropical areas. Here are the 5 major differences between Hydra and the rest of the species of Hydrazoa:

1. The first difference is that the Hydra is able to progress only till the polyp stage and undergoes mostly asexual reproduction through bud formation. However, when the conditions are hard, it can switch to sexual reproduction. However, rest of the hydrozoans develop and go through a stage from polyp to adult form which is known as medusa that requires sexual reproduction.
2. The hydra is a genus which is able to grow only in freshwater and when it comes to the hydrozoans, they are even able to grow in marine water and freshwater both.
3. The hydras are those which are able to grow solitary and they are able to undergo regeneration. When it comes to rest of the hydrozoans, they are able to grow and survive mostly in colonies although some also grows solitary
4. In hydra, they are able to undergo tissue regeneration which means a part will bud off and it will be responsible for formation of a new individual. Each of the half of hydra when cut off will be able to regenerate a complete hydra. The rest of the hydrozoa are able to reproduce through both sexual and asexual means where the formation of polyps is majorly asexual reproduction and the formation of medusa is sexual reproduction.
5. The hydra mostly follow a sedentary lifestyle and hence it mostly does not go looking for food and wait for it to come. They have extensible tentacles which helps in getting hold of the food. The rest of the hydrazoans have a mobile lifestyle and they undergo movement looking for food.