Fast Facts: Cnidarians
- Scientific Name: Cnidaria
- Common Name (s): Coelenterates, corals, jellyfish, sea anemones, sea pens, hydrozoans
- Basic Animal Group: Invertebrate
- Size: 3/4 of an inch to 6.5 feet in diameter; up to 250 feet long
- Weight: Up to 440 pounds
- Lifespan: A few days to more than 4,000 years
- Diet: Carnivore
- Habitat: Found in all the world's oceans
What animals live in cnidarians?
cnidarian, also called coelenterate, any member of the phylum Cnidaria (Coelenterata), a group made up of more than 9,000 living species. Mostly marine animals, the cnidarians include the corals, hydras, jellyfish, Portuguese men-of-war, sea anemones, sea pens, sea whips, and sea fans. The phylum Cnidaria is made up of four classes: Hydrozoa (hydrozoans); Scyphozoa (scyphozoans); Anthozoa ...
What are facts about cnidarians?
Phylum Cnidaria
- Most Cnidarians do not have eyes or any type of developed organs.
- The phylum cnidarian consists of about 10,000 species of simple animals found only in marine habitats.
- It is best not to touch very small jellyfish, or any jellyfish AT ALL. ...
- Jellyfishes are made up of more than 95% water and they have no brains, blood or nervous system.
What are 5 characteristics of cnidarians?
What characteristics do cnidarians have?
- 5 main features of cnidarians. soft bodied, carnivorus, with stinging tentacles, body symmetry, and specialized tissue.
- 3 groups of cnidarians. jellyfish, hydras (and relatives), and sea anemones and coral.
- statocyst.
- ocelli.
- human activities that hurt coral.
What are the types of cnidarians?
There are four major groups of cnidarians:
- Anthozoa, which includes true corals, anemones, and sea pens;
- Cubozoa, the amazing box jellies with complex eyes and potent toxins;
- Hydrozoa, the most diverse group with siphonophores, hydroids, fire corals, and many medusae; and.
- Scyphozoa, the true jellyfish.
What are the most common types of cnidarians?
There are four major groups of cnidarians:Anthozoa, which includes true corals, anemones, and sea pens;Cubozoa, the amazing box jellies with complex eyes and potent toxins;Hydrozoa, the most diverse group with siphonophores, hydroids, fire corals, and many medusae; and.Scyphozoa, the true jellyfish.
What is the name Cnidaria derived from?
The phylum Cnidaria (pronounced “nih DARE ee uh”) includes soft-bodied stinging animals such as corals, sea anemones, and jellyfish (Fig. 3.23 A). The phylum's name is derived from the Greek root word cnid- meaning nettle, a stinging plant. Cnidarians are found in many aquatic environments.
Why is phylum Cnidaria called so?
Phylum Coelenterata is also known as Cnidaria due to the presence of cnidoblasts or cnidocytes on the tentacles and body surface. They contain stinging capsules called nematocysts.
What do cnidarians have in common?
Cnidarians share several basic characteristics. All Cnidaria are aquatic, mostly marine, organisms. They all have tentacles with stinging cells called nematocysts that they use to capture food. Cnidarians only have two body layers, the ectoderm and endoderm, separated by a jelly-like layer called the mesoglea.
What does the term Cnidaria mean?
Medical Definition of Cnidaria : a phylum of more or less radially symmetrical invertebrate animals that lack a true body cavity, possess tentacles studded with nematocysts, and include the hydroids, jellyfishes, sea anemones, and corals.
How do you say cnidarians?
0:051:01How To Say Cnidarians - YouTubeYouTubeStart of suggested clipEnd of suggested clipLa idea viene ley de aliens.MoreLa idea viene ley de aliens.
What are the 4 types of cnidarians?
Types of Cnidarians. There are five main cnidarian classes: Anthozoa, Hydrozoa, Cubozoa, Scyphozoa, and Staurozoa.
What are the types of cnidarians?
Portuguese man o' warSea anemoneMedusozoaSea anemones and coralsMoon jellyBox jellyfishCnidaria/Lower classifications
What are the 3 classes of cnidarians?
Major Groups of Cnidarians. Cnidarians are divided into three major classes. These are the Hydrozoa (hydras and other colony-forming species), the Scyphozoa (jellyfish), and the Anthozoa (sea anemones and corals).
What is an example of a cnidarian?
Portuguese man o' warSea anemoneMedusozoaSea anemones and coralsMoon jellyBox jellyfishCnidaria/Lower classifications
What are cnidarians made of?
Cnidarians consist of two cell layers: an outer ectoderm and an inner endoderm (the gastrodermis) that lines the coelenteron.
What are 5 facts about cnidarians?
Fast Facts: CnidariansScientific Name: Cnidaria.Common Name(s): Coelenterates, corals, jellyfish, sea anemones, sea pens, hydrozoans.Basic Animal Group: Invertebrate.Size: 3/4 of an inch to 6.5 feet in diameter; up to 250 feet long.Weight: Up to 440 pounds.Lifespan: A few days to more than 4,000 years.Diet: Carnivore.More items...•
What language was the word Cnidaria derived from and what does the word mean?
Cnidarian comes from the Greek word "cnidos" meaning stinging nettle.
Who coined the term Cnidaria?
The name Cnidaria comes from the Greek word "cnidos," which means stinging nettle. Term Coelenterata and Cnidaria were given by Leuckart and Hyman.
Why Cnidaria is called minor phyla?
The members that falls under this phylum are generally marine and are sessile and free swimming type. 3. They exhibit the property of bilateral symmetry and are diploblastic type of animals.
How are cnidarians classified?
Cnidarians are classified into four main groups: non-moving (sessile) Anthozoa (sea anemones, corals, sea pens); Cubozoa (box jellies);swimming Scyphozoa (jellyfish); and Hydrozoa, a broad group that includes all the freshwater cnidarians as well as many marine forms. There are about 10, 000 species of Cnidarians.
What is the scientific name of the cnidaria?
Scientific Name: Cinadaria. Jennifer Kennedy, M.S., is an environmental educator specializing in marine life. She serves as the executive director of the Blue Ocean Society for Marine Conservation. The Cnidaria ( Cnidaria spp.) is the phylum of animals that contains corals, jellyfish (sea jellies), sea anemones, sea pens, and hydrozoans.
What are the two types of cnidarians?
There are two types of cnidarians, called polypoid and medusoid. Polypoid cnidarians have tentacles and a mouth that face up (think of an anemone or coral). These animals are attached to a substrate or colony of other animals. Medusoid types are those like jellyfish—the "body" or bell is on top and tentacles and mouth hang down.
What is the phylum of cnidaria?
The Cnidaria ( Cnidaria spp.) is the phylum of animals that contains corals, jellyfish (sea jellies), sea anemones, sea pens, and hydrozoans. Cnidarian species are found throughout the world and are quite diverse, but they share many similar characteristics.
How big is a cnidaria?
The smallest Cnidaria is the Hydra, which measures under 3/4 of an inch; the largest is the lion's mane jellyfish which has a bell that can measure more than 6.5 feet in diameter; including its tentacles. it can exceed 250 feet long. Dania Chesham/Getty Images.
How do cnidarians interact with humans?
There are many ways cnidarians may interact with humans: They may be sought-after in recreational activities, such as scuba divers going to reefs to look at corals. Swimmers and divers may also need to beware of certain cnidarians because of their powerful stings. Not all cnidarians have stings that are painful to humans, but some do, and some may even be fatal. Some cnidarians, such as jellyfish, are even eaten. Different cnidarian species may also be collected for trade for aquariums and jewelry.
How do cnidarians reproduce?
Cnidarians can reproduce asexually by budding (another organism grows off the main organism, such as in anemones), or sexually, in which spawning occurs. Male and female organisms release sperm and eggs into the water column, and free-swimming larvae are produced.
What is the coelenteron?
Digestive Cavity (The Coelenteron): The coelenteron contains their stomach, gullet, and intestines; it has one opening, which serves as both the mouth and anus, so cnidarians eat and expel waste from the same location.
What are cnidarian colonies made of?
Many cnidarian species produce colonies that are single organisms composed of medusa-like or polyp -like zooids, or both (hence they are trimorphic ). Cnidarians' activities are coordinated by a decentralized nerve net and simple receptors.
Why are cnidarians limited to shallow waters?
Many cnidarians are limited to shallow waters because they depend on endosymbiotic algae for much of their nutrients. The life cycles of most have polyp stages, which are limited to locations that offer stable substrates. Nevertheless, major cnidarian groups contain species that have escaped these limitations. Hydrozoans have a worldwide range: some, such as Hydra, live in freshwater; Obelia appears in the coastal waters of all the oceans; and Liriope can form large shoals near the surface in mid-ocean. Among anthozoans, a few scleractinian corals, sea pens and sea fans live in deep, cold waters, and some sea anemones inhabit polar seabeds while others live near hydrothermal vents over 10 km (33,000 ft) below sea-level. Reef -building corals are limited to tropical seas between 30°N and 30°S with a maximum depth of 46 m (151 ft), temperatures between 20 and 28 °C (68 and 82 °F), high salinity, and low carbon dioxide levels. Stauromedusae, although usually classified as jellyfish, are stalked, sessile animals that live in cool to Arctic waters. Cnidarians range in size from a mere handful of cells for the parasitic myxozoans through Hydra' s length of 5–20 mm ( 1⁄4 – 3⁄4 in), to the Lion's mane jellyfish, which may exceed 2 m (6 ft 7 in) in diameter and 75 m (246 ft) in length.
What do cnidarians eat?
Many are preyed on by other animals including starfish, sea slugs, fish, turtles, and even other cnidarians.
How do cnidarians get their food?
Cnidarians feed in several ways: predation, absorbing dissolved organic chemicals, filtering food particles out of the water , obtaining nutrients from symbiotic algae within their cells, and parasitism. Most obtain the majority of their food from predation but some, including the corals Hetroxenia and Leptogorgia, depend almost completely on their endosymbionts and on absorbing dissolved nutrients. Cnidaria give their symbiotic algae carbon dioxide, some nutrients, a place in the sun and protection against predators.
How many layers does a cnidarian have?
Cnidaria are diploblastic animals; in other words, they have two main cell layers, while more complex animals are triploblasts having three main layers. The two main cell layers of cnidarians form epithelia that are mostly one cell thick, and are attached to a fibrous basement membrane, which they secrete.
What is the name of the phylum of sea nettles?
Pacific sea nettles, Chrysaora fuscescens. Cnidaria ( / nɪˈdɛəriə, naɪ -/) is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey.
Why do cnidaria have a hydrostatic skeleton?
This improves respiration after feeding and allows these animals, which use the cavity as a hydrostatic skeleton, to control the water pressure in the cavity without expelling undigested food. Cnidaria that carry photosynthetic symbionts may have the opposite problem, an excess of oxygen, which may prove toxic.
What are cnidarians?
Cnidarians are a diverse group of invertebrates that come in many shapes and sizes but there are some basic features of their anatomy that most share in common. 01. of 10.
What are the two forms of a cnidarian?
Cnidarians take on two basic forms, a medusa and a polyp. The medusa form is a free-swimming structure which consists of an umbrella-shaped body (called a bell), a fringe of tentacles that hang from the edge of the bell, a mouth opening located on the underside of the bell, and a gastrovascular cavity.
What are the different types of corals?
Corals belong to a group of cnidarians known as the Anthozoa. There are many types of coral and it should be noted that the term coral does not correspond to a single taxonomic class. Some groups of corals include: 1 Alcyonacea (soft corals) 2 Antipatharia (black corals and thorny corals) 3 Scleractinia (stony corals)
What is the internal sac of a cnidaria?
Purestock / Getty Images. Cnidarias have an internal sac for digestion which is called the gastrovascular cavity. The gastrovascular cavity has only one opening, a mouth, through which the animal takes in food and releases waste. Tentacles radiate outward from the rim of the mouth.
How many arms does a jellyfish have?
For example, many jellyfish have four oral arms that extend below their body and their body structure can therefore be divided into four equal parts. This type of radial symmetry is referred to as tetramerism. Additionally, two groups of cnidarians, corals and sea anemones, exhibit six- or eight-fold symmetry.
What is the outer layer of a cnidarian?
The body wall of a cnidarian consists of three layers, an outer layer known as the epidermis, a middle layer called the mesoglea, and an inner layer referred to as the gastrodermis. The epidermis contains a collection of different types of cells. These include epitheliomuscular cells which contract and enable movement, ...
When is the radial symmetry of jellyfish apparant?
The radial symmetry of these jellyfish is apparant when they are viewed top-down.
Description
Species
- The Cnidaria phylum is made up of several classes of invertebrates: 1. Anthozoa(sea anemones, corals); 2. Cubozoa(box jellyfish); 3. Hydrozoa(hydrozoans, also known as hydromedusae or hydroids); 4. Scyphozoaor Scyphomedusae (jellyfish); and the 5. Staurozoa(stalked jellyfish).
Habitat and Distribution
- With thousands of species, cnidarians are diverse in their habitat and are distributed in all the world's oceans, in polar, temperate, and tropical waters. They are found in a variety of water depths and closeness to shore depending on the species, and they may live anywhere from shallow, coastal habitats to the deep sea.
Diet and Behavior
- Cnidarians are carnivores and use their tentacles to feed on planktonand other small organisms in the water. They fish using their stinging cells: when a trigger at the end of the cnidocyte is activated, the thread unfurls outward, turning inside out, and then the thread wraps around or stabs into the tissue of the prey, injecting a toxin. Some cnidarians, such as corals, are inhabite…
Reproduction and Offspring
- Different cnidarians reproduce in different ways. Cnidarians can reproduce asexually by budding (another organism grows off the main organism, such as in anemones), or sexually, in which spawning occurs. Male and female organisms release sperm and eggs into the water column, and free-swimming larvae are produced. Cnidarian life cycles are complex and vary within the classe…
Conservation Status
- Cnidarians such as jellyfish are likely to be tolerant of climate change—in fact, some are even thriving and ominously taking over the habitats of other lifeforms—but corals (such Acroporaspp) are listed as threatened by ocean acidification and environmental damage, according to the International Union for Conservation of Nature (IUCN).
Cnidarians and Humans
- There are many ways cnidarians may interact with humans: They may be sought-after in recreational activities, such as scuba divers going to reefs to look at corals. Swimmers and divers may also need to beware of certain cnidarians because of their powerful stings. Not all cnidarians have stings that are painful to humans, but some do, and some may even be fatal. Some cnidari…
Sources
- Coulombe, Deborah A. 1984. The Seaside Naturalist. Simon & Schuster.
- Fautin, Daphne G. and Sandra L. Romano. 1997. Cnidaria. Sea anemones, corals, jellyfish, sea pens, hydra. Version 24 April 1997. The Tree of Life Web Project, http://tolweb.org/.
- "Listed Animals." Environmental Conservation Online System, U.S. Fish and Wildlife Service.
- Petralia, Ronald S., Mark P. Mattson, and Pamela J. Yao. "Aging and Longevity in the Simples…
- Coulombe, Deborah A. 1984. The Seaside Naturalist. Simon & Schuster.
- Fautin, Daphne G. and Sandra L. Romano. 1997. Cnidaria. Sea anemones, corals, jellyfish, sea pens, hydra. Version 24 April 1997. The Tree of Life Web Project, http://tolweb.org/.
- "Listed Animals." Environmental Conservation Online System, U.S. Fish and Wildlife Service.
- Petralia, Ronald S., Mark P. Mattson, and Pamela J. Yao. "Aging and Longevity in the Simplest Animals and the Quest for Immortality."Ageing Research Reviews16 (2014): 66-82. Print.
Overview
Cnidaria is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter.
Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like subs…
Ecology
Many cnidarians are limited to shallow waters because they depend on endosymbiotic algae for much of their nutrients. The life cycles of most have polyp stages, which are limited to locations that offer stable substrates. Nevertheless, major cnidarian groups contain species that have escaped these limitations. Hydrozoans have a worldwide range: some, such as Hydra, live in freshwater; Obelia appears in the coastal waters of all the oceans; and Liriope can form large sho…
Distinguishing features
Cnidarians form a phylum of animals that are more complex than sponges, about as complex as ctenophores (comb jellies), and less complex than bilaterians, which include almost all other animals. Both cnidarians and ctenophores are more complex than sponges as they have: cells bound by inter-cell connections and carpet-like basement membranes; muscles; nervous systems; and some have sensory organs. Cnidarians are distinguished from all other animals by having cni…
Description
Most adult cnidarians appear as either free-swimming medusae or sessile polyps, and many hydrozoans species are known to alternate between the two forms.
Both are radially symmetrical, like a wheel and a tube respectively. Since these animals have no heads, their ends are described as "oral" (nearest the mouth) and "aboral" (furthest from the mouth).
Reproduction
Cnidarian sexual reproduction often involves a complex life cycle with both polyp and medusa stages. For example, in Scyphozoa (jellyfish) and Cubozoa (box jellies) a larva swims until it finds a good site, and then becomes a polyp. This grows normally but then absorbs its tentacles and splits horizontally into a series of disks that become juvenile medusae, a process called strobilation. Th…
Classification
Cnidarians were for a long time grouped with Ctenophores in the phylum Coelenterata, but increasing awareness of their differences caused them to be placed in separate phyla. Modern cnidarians are generally classified into four main classes: sessile Anthozoa (sea anemones, corals, sea pens); swimming Scyphozoa (jellyfish) and Cubozoa (box jellies); and Hydrozoa, a diverse group t…
Evolutionary history
The earliest widely accepted animal fossils are rather modern-looking cnidarians, possibly from around 580 million years ago, although fossils from the Doushantuo Formation can only be dated approximately. The identification of some of these as embryos of animals has been contested, but other fossils from these rocks strongly resemble tubes and other mineralized structures ma…
Interaction with humans
Jellyfish stings killed about 1,500 people in the 20th century, and cubozoans are particularly dangerous. On the other hand, some large jellyfish are considered a delicacy in East and Southeast Asia. Coral reefs have long been economically important as providers of fishing grounds, protectors of shore buildings against currents and tides, and more recently as centers of tourism. However, they ar…