Cnidarian or coelenterate members of the cnidarian phylum, a group of over 9000 species. Most of these are marine animals like corals, jellyfish, hydras, sea anemones, sea fans, and sea whips.
The cnidarians are part of the animal kingdom, and examples are jellyfish, corals, sea anemones, and hydrozoans. The species can be found throughout the world and are quite diverse. When the cnidarian gets damaged, these can regenerate their body parts, making them immortal.
Even though the scientific name is 'Cnidaria', they go by their common names. Here are some interesting facts about Cnidaria.
Cnidaria is of two kinds. These are polypoid and medusoid.
Cnidaria are a diverse species in their habitat, and these can be found across the world's oceans. They are found in temperate polar and tropical waters. Depending on their species, the cnidarian's habitats can be found across several water depths and close to the shore. These can survive in shallow waters, deep-sea and coastal habitats.
Cnidaria are carnivorous, and they make use of their tentacles to feed on the plankton and other smaller water organisms. They use their stinging cells to fish when the trigger at the cnidocyte end is activated. This causes the thread to unfurl outwards, turning it inside out. The thread then wraps around and stabs the prey tissue, injecting a toxin.
Some of the Cnidaria, like the corals, are inhabited by algae that go through photosynthesis. This is a process through which it gets carbon to the Cnidaria host. In a group, the Cnidaria can regenerate and reorganize their bodies. This may mean that these are immortal. The oldest of the Cnidaria are the corals in the reef known to live for over 4000 years. There are, however, some kinds of polyp that live just for 4 to 8 days.
Different Cnidaria species reproduce in various ways. These can reproduce asexually, which is by budding. In this process, a new organ grows from the main organism. Or they could reproduce sexually, like when spawning happens. The male and the female release the sperm and the egg in the water column, producing the free-swimming larvae.
The life cycle of the Cnidaria is complex, and this varies within classes. The archetypal life cycle of the Cnidaria starts as zooplankton, and this develops into the sessile polyp stage. The polyps are then attached to the seabed, which buds off into a water-free swimming medusa stage. However, some species stay as polyp-like coral reefs.
Cnidaria, like the jellyfish, is likely tolerant to climatic change. Some are thriving and take over the habitat of other forms of life. Corals are, however, threatened because of the environmental damage and the acidification in the oceans.
Cnidaria may interact with humans in various ways. These are sought in recreational activities like the scuba divers who go to the reefs to see the corals. It is important to know that not all Cnidaria are safe. If you go near them, they may sting.
Some could even be fatal. There are certain Cnidaria that can be eaten. These could be collected for trade to keep in aquariums or make jewelry.
1. What are 5 examples of cnidarians?
2. What are the characteristics of Cnidaria?
3. Why are cnidarians important?
They are predators in the ocean sea. They are a crucial part of the marine ecosystem where they engage in a symbiotic relationship with the other organism. Their predatory activity ensures a delicate balance in the ocean's food chain.
4. How do cnidarians breathe?
Gas exchange in cnidarians happens through direct diffusion.
5. How do cnidarians move?
They move by jet propulsion.
6. How do cnidarians feed?
The cnidarians use their cnidae and the associated toxin to capture food.
7. Where are cnidarians found in the world?
The cnidarians can be found in all the ocean habitats.
8. How do cnidarians sense their environment?
The nerve net in the cnidarian serves as a sensory locator. The nerve cell stretches around the animal's body and lets the cnidarian detect any chemical changes. They use these senses to capture the prey and to move in response to stimuli. The expansive nerve net is known as the diffuse nerve net.
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