Ctenophores are soft-bodied, free-swimming marine animals having biradial symmetry and comb-like ciliary plates for movement. They are devoid of nematocytes. They are also known as sea walnuts or comb jellies. Members of this Phylum are exclusively aquatic creatures that live on the ocean's surface or at its bottom.
Classification of Phylum Ctenophora
Ctenophores are classified into two groups and many orders based on their body shapes and features. Ctenophora is split into two groups based on the presence or lack of tentacles.
1. Tentaculate
- It is a class of organisms that have tentacles.
- Usually two, long and retractile tentacles.
- Tentacles bear colloblasts (adhesive cells)
- Oval or spherical body
Examples: Pleurobrachia, Ctenoplana
2. Nuda
- Organisms without tentacles.
- It consists large and wide mouth
- Body laterally compressed
- Active predators
Examples: Beroe
Characteristics of Phylum Ctenophora
- These species are only found in the sea.
- This Phylum's animals are solitary and free-swimming.
- They have a diploblastic acoelomate body structure.
- The body is translucent, gelatinous, soft, and segmented, with two long, solid, retractile tentacles.
- These species have bilateral symmetry.
- Tissue-level organisation is seen in these invertebrates.
- They move by using eight strips of cilia called comb rows. These comb-like rows aid in movement.
- Reproduction happens through sexual methods because they are hermaphrodite animals.
- External fertilisation and indirect development are used by these species.
- They have both an external and an intracellular digestive system.
- For balance, they have an aboral sensory organ called the statocyst.
Importance of Phylum Ctenophora
1. Economic Importance
- They create stunning vistas while diving and snorkelling.
- One advantage of Ctenophora was its genetics. The light created quickly by Ctenophores is employed as a "biomarker" or "biotag."
- Scientists employ them in studies to uncover activation genes by making various luminous cats, mice, and other animals and determining if the genetic alterations made to these animals are functioning.
2. Ecological Importance
- They reproduce fast and are effective predators, so they keep the plankton population under control.
- They may hunger and shrink when food is scarce, and they can adapt to higher temperatures, giving them an edge in changing climatic conditions.