Cnidaria is a large phylum composed of some of the most beautiful of all the salt and freshwater organisms: the true jellyfish, box jellyfish, coral and sea anemones, and hydra. Although Cnidaria is an incredibly diverse group of animals, there are several traits that link them together.
Most cnidarians are dipoblastic, which means that they are composed of only two layers of cells. The outer layer is known as the ectoderm or epidermis, and the inner layer is known as the endoderm or gastrodermis. These layers contain the nerve nets that control the muscular and sensory functions of the animal. Between these layers is a jelly-like noncellular substance known as mesoglea, which in true jellyfish constitute the vast bulk of the animal (hence their common name). In other species, the mesoglea may be nearly absent. All cnidarians have a single opening into the body which acts as both the mouth and anus, taking in food and expelling waste. In most species the mouth is lined with tentacles which act to capture food. The mouth leads to a body cavity known as the coelenteron, where the food is digested. This body cavity has given this phylum its other, less commonly used, name of Coelenterata.
Cnidarians have a complex life cycle that, depending on the species, may alternate between two forms. The first form is known as a polyp, which is sessile (anchored to one spot). The polyps are tubular in shape, with the mouth, often lined with tentacles, facing upwards. The bodies often con...
Because of its size and abundance, T. californicus is commonly regarded as the insect of the sea. This creature is generally very small, from 1-3 mm in size as adults. They are cylindrically shaped, and have a segmented body (head, thorax, abdomen) though no noticeable division between body regions (Powlik 1966). Each segment of the body has a pair of legs. They use their 'legs' to propel themselves through the water in short rapid jerks. They have 2 pairs of long feathered antennae, a chitin us exoskeleton and a single eye in the middle of their head, this simple eye can only differentiate between light and dark.
Throughout history, there have been countless women who have seized the opportunities afforded to them by fate to their advantage. Despite the oppression of patriarchal societies, these pioneers carved a place for themselves on the walls of the past. Clodia Metelli, who was a Roman aristocrat born in 95 BC, was one of most enigmatic female figures to emerge from ancient Rome. Clodia was a descendant of a powerful line of politicians, so she was soon swept into a world of wealth. Because she was connected to potent people, Clodia seized the opportunity to expand her influence over the political climate in ancient Rome. By utilizing the authority of those around her to gain her own, Clodia Metelli effectively
In the phylum Mollusca, there are many organisms that have body parts that change as the environment around them change; such as the octopus. An octopus can camouflage to variety of objects in its environment. Each organism in the Mollusca phylum has a type of foot that stows mobility and they eat by a radula. The radula is strap like tongue that has very sharp teeth and they can change to be different shapes or sizes based on their prey. They have a pseudo coelomate body plan, meaning that they have a coelom that exists, but it is lined by mesoderm only on the body wall, not around the gut. This video enhanced my understanding standing of the phylum Mollu...
Imagine a creature that has a skeleton on the outside of its body, that has eyes that protrude on stalks, and whose blood doesn't flow through blood vessels but, instead, pools and surrounds body tissues. What is this monstrous creature? What if I were to tell you this isn't a monster, but something you've probably seen and maybe even eaten?! Yep, this strange creature is a __crustacean__! There are over 50,000 species of crustacean and they come in all shapes and sizes, from an ocean-dwelling crab to an immobile barnacle! But before we delve into the types of crustaceans, let's take a moment to go over the characteristics and anatomy they share.
The “water bear” is a common name for a group of a little over 100 genera of protozoans grouped under the Phylum Tardigrada and is a relative of the Phylum Arthropoda. The phylum Tardigrada contains over 1000 species, and is grouped into three classes. There are two main classes the Heterotarigrada ad the Eutardigrada. The last is the Mesotardigrada and contains only one species, that was discovered in a sulfur spring in Japan 1937, and has not been seen since. “Water bears” are, as with most species, separated into groups by characteristics and more recently molecular genetic methods. The Heterotarigrada are known mainly for their hair like tufts on appendages and hard-undivided flattened scales. The Eutardigrada are known as “naked tardigrades” because they lack the hard scales or have several separate plates. Tardigrades are then divide further into orders by comparing groups for cuticle appearance, feeding tube, claws, and other defining features (Michalczyk, 2014).
Flatworms belong to the phylum Platyhelminthes. They have the simplest body plan of all bilaterally symmetrical animals. They are called flatworms because their bodies are compressed. The mouth is the only opening into the digestive cavity the flatworms have. Food is taken in through this hole and wastes are discharged also through this hole. Flatworms have a well-defined nervous, muscular, excretory, and reproductive system. The flatworm distributes the food it digests through a digestive tube that branches throughout all of its body parts. The fact that the worm’s body is flat serves many purposes. It allows the worm to hid in small spaces, to fit into the opening of other animals if the worm is parasitic, and it means that all the cells are close enough to the surface for exchange of oxygen and carbon dioxide with the environment (Meinkoth 399).
They are invertebrates (spineless animals) and are cousins of anemones and jellyfish. When thousands of these animals are grouped together, they are referred to as coral colonies. Each coral "tree" or "mound" is one colony of coral polyps. A polyp has a sac-like body and an opening or mouth encircled by stinging tentacles called cnidae.
to the lobster and crab. Their closest living relative today is the horseshoe crab.The name
Fox, R. 2001. Invertebrate Anatomy OnLine: Artemia Franciscana. Lander University. http://webs.lander.edu/rsfox/invertebrates/artemia.html, retrieved February 13, 2011.
The outer layer of a reef consists of living animals, or polyps, of coral. Single-celled algae called zooxanthellae live within the coral polyps, and a skeleton containing filamentous green algae surrounds them. The photosynthetic zooxanthellae and green algae transfer food energy directly to the coral polyps, while acquiring scarce nutrients from the coral. The numerous micro habitats of coral reefs and the high biological productivity support a great diversity of other life.
Soft corals are grouped in the phylum Cnidaria, class Anthozoa, and order Alcyonacea. Their distinguishing characteristic is that their polyps always bear eight tentacles which are on both edges fringed by rows of pinnules (Fabricius and De’ath, 2002). The common name “soft coral” comes from the fact that they have no massive external skeleton as compared to the more commonly studied hard corals.
... The Web. 4 Feb. 2014. Campbell, Neil A., and Jane B. Reece. Biology.
Comb jellies or Ctenophores are basically fake jellyfish. Like jellyfish they are transparent are transparent, but these lacking stinging cells are basically giant balls of see-through goo. These balls of goo are located throughout most marine environments, at varied depths and temperatures they are very good conformers. The most prominent feature of Ctenophores is their cilia. Cilia are hair-like structures that are used to help this species swim. Being fake jellyfish the comb jellies are extremely predacious, they entrap food and suck them up and are known for being cannibalistic and swallowing each other whole.