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Cnidarians
Cnidarians are aquatic animals belonging to the phylum Cnidaria. Common cnidarians include to jellyfish, sea anemones, corals and the Portuguese Man o' War. Questions about all species of cnidarians can be directed here.
669 Questions
Cnidarians are actually carnivorous fauna. Cnidarians are either polyps, such as sea anemones or coral, or free-floating medusae, such as jellyfish.
Polyps have a tube-like body with an opening on top that is surrounded by outward- and upward-facing tentacles.
Medusae are usually bell-shaped animals with a concave oral surface, or mouth, and tentacles that dangle downward from the rim of an umbrella-like body.
Four classes make up the phylum Cnidaria:
Anthozoa, which includes sea anemones and coral
Cubozoa, which includes Portuguese man-of-war
Hydrozoa, which includes jellyfish
Scyphozoa, which includes box jellies
Cnidarians live in aquatic environments and inhabit all depths, from the sandy substrate up to the surface. Some are even found in freshwater.
Cnidarian bodies have only one opening that serves as both mouth and anus. Food enters through the mouth and excess food and waste leave through the mouth as well.
Cnidarians have no need for a brain or a heart; instead, these animals have specialized tissues to coordinate basic bodily functions. A decentralized net of nerves and receptors allows the animals to negotiate their environment, whether they are moving about, detecting danger, or making a meal of any prey that swims by.
Unfortunatly, i don't think there are any official studies on hydras. i wouldn't know. all i know is that if you cut their heads off, they only come back doubled.
What are the two layers of tissue in the hydra?
Hydra is in the phylum of the cnidarians which is a radical symmetry. so ectoderm, the outer layr which form the nerve sytem. Also, the endoderm, the inner layer are presented in the hydra.
Hydras are non-senescent, which means their mortality rate does not increase with age. This means they do not have a definite lifespan
Is hydra sessile or non sessile?
a hydra as a polyp is not sessile but when it grows to be a hydra it is sessile
How transportation of materials occurs in hydra and sponges?
These organisms are very simpleand they do not require a circulatory system. Since their body wall is very thin, they are surrounded by water. Substnces can easily diffuse in and out of the body. Their simple structure helps them in circulation.
A cavity that serves both digestive and circulatory purpose in some cnidarians?
A cavity that both digestive and circulatory serve are called cylindrical. This is the purpose of cnidarians.
Hydraform blocks are building blocks that can be used in the construction of houses, schools, clinics, walls, horse stables or any other type of building you can think of.
The blocks are made from a mixture of soil and cement, and are interlocking.
This saves money in construction as low amounts of cement is used, and interlocking blocks mean that you require almost no mortar when constructing buildings or walls.
The blocks are produced with a Hydraform block machine. Hydraform blocks are made from soil from locally dug earth, mixed with cement. The mixture is then hydraulically compressed to produce a building block. The blocks are very strong and durable and many buildings have been constructed in over 70 countries worldwide.
Why is a sea anemone not streamlined but penguins are?
penguins bodies are streamlined to reduce drag in water so they can swim but sea anemone don't need to swim I think
Is someting which eats a sea anemone a carnivore?
Yes a jellyfish eating animal is a carnivore as the jellyfish is a living thing
They don't technically have a brain. Echinoderms have a simple radial nervous system with a nerve net, like in jellyfish but different. The nerve net has no central brain, although there may be ganglia present.
How does method by which cnidarians obtain food differ from method by which poriferans obtain food?
Poriferans needs organic substances and cnidarians needs of a gastrovascular cavity with openings.
Why do the Children of the Hydras Teeth always ask for a mop when they drink a glass of milk?
Because it is good for them
Yes but not all. Because a mantle is a hard substance that cells secret. Example: clams Hydra ,a type of cnidarian, does not have this. :)
Does a hydra have bilateral or radial symmetry?
The hydra has radial symmetry. The hydra belongs to the phylum Cnidaria and many immobile species in this phylum exhibit radial symmetry. Some marine animals that have bilateral symmetry are fish, sea turtles, and marine mammals.
How does cnidarians circulatory system work?
ITS FLIPPIN GAY!
ITS FLIPPIN GAY!
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Actually they dont have a circulatory system
Why are Cnidarian considered simple but deadly?
Cnidarians are jellyfish. They have a very simple body structure and nervous system, but some species, including the box jellyfish and the Irukandji, produce toxin that has been lethal to humans.
