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Hydroids (genus Obelia) are from the class Hydrozoa, which consists of mainly marine and some freshwater species and have both the polyp and medusa stages in their life cycle. The genus belongs to the phylum Cnidaria, which are all aquatic and mainly marine organisms that are relatively simple in structure. I took this picture last summer with a Zeiss MRc5 digital camera and a Zeiss stereomicroscope This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ...
Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ...
Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Subregnum Bilateria Acoelomorpha Orthonectida Rhombozoa Myxozoa Superphylum Deuterostomia Chordata (vertebrates, etc. ...
Phyla Radiata Cnidaria Ctenophora - Comb jellies Bilateria Protostomia Acoelomorpha Platyhelminthes - Flatworms Nemertina - Ribbon worms Gastrotricha Gnathostomulida - Jawed worms Micrognathozoa Rotifera - Rotifers Acanthocephala Priapulida Kinorhyncha Loricifera Entoprocta Nematoda - Roundworms Nematomorpha - Horsehair worms Cycliophora Mollusca - Mollusks Sipuncula - Peanut worms Annelida - Segmented worms Tardigrada - Water bears Onychophora - Velvet worms Arthropoda - Insects, etc. ...
Classes Anthozoa - Corals and sea anemones Cubozoa - Sea wasps or box jellyfish Hydrozoa - Hydroids, hydra-like animals Scyphozoa - Jellyfish Cnidaria (from New Latin cnida nematocyst, fr. ...
Orders Actinulida Capitata Chondrophora Filifera Hydroida Siphonophora Trachylina Organisms that are in Class Hydrozoa come from the Phylum Cnidaria. ...
In biology, a genus (plural genera) is a grouping in the classification of living organisms having one or more related and morphologically similar species. ...
Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ...
Orders Actinulida Capitata Chondrophora Filifera Hydroida Siphonophora Trachylina Organisms that are in Class Hydrozoa come from the Phylum Cnidaria. ...
In biology, the most commonly used definition of species was first coined by Ernst Mayr. ...
In zoology, a polyp is one of two forms of individuals found in many species of cnidarians. ...
In biology, a medusa (also known as a hydromedusa) is a form of cnidarian in which the body is shortened on its principal axis and broadened, sometimes greatly, in contrast with the hydroid or polyp. ...
Phylum is one of the levels of scientific classification of organisms; see the Phylum (biology) article. ...
Classes Anthozoa - Corals and sea anemones Cubozoa - Sea wasps or box jellyfish Hydrozoa - Hydroids, hydra-like animals Scyphozoa - Jellyfish Cnidaria (from New Latin cnida nematocyst, fr. ...
Habitat The Obelia are naturally found underwater in the ocean throughout the world. They are marine colonial hydrozoans that are found growing on algae and hard substrata in the subtidal zones. They can be found preferentially no deeper than 200 m from the water surface, growing in intertidal rockpools and at extreme low water of spring tides. These colonies also attach themselves to artificial substrata, such as pilings, harbor installations, buoys, bridge supports, as well as to bivalve cultures and floating debris. Obelia is a cold water organism, living in places where water movement plays an important role to supply adequate food, gas exchange, remove waste products, prevent excessive siltation, and provide suitable substratum. Many hydroids are likely to be plentiful where water movement is sufficient, but not so strong as to cause damage. Hydroids tend to occur in low light conditions, possibly due reduced competition from algae and/or settlement preferences of their planulae larvae. A seaweed (Laurencia) up close: the branches are multicellular and only about 1 mm thick. ...
Orders Subclass Protobranchia Solemyoida Nuculoida Subclass Pteriomorphia - oysters Arcoida Mytiloida Pterioida Subclass Paleoheterodonta - mussels Trigoinoida Unionoida Subclass Heterodonta - clams, zebra mussels Veneroida Myoida Subclass Anomalosdesmata Pholadomyoida Animals of the Class Bivalvia are known as bivalves because they typically have two-part shells, with both parts being more or less symmetrical. ...
Respiration can refer to: Cellular respiration, which is the use of oxygen in the metabolism of organic molecules. ...
Life Cycle The Obelia life cycle first starts out with the sessile, asexually reproducing polyp colony. During this stage of life, Obelia are suspended to substrate surfaces. On this mature colony there are individual hydranths called gastrozooids, which can be found expanded or contracted, to aid in the growth of this organism by feeding; and the reproductive polyp gonozooids that have medusa buds. Other hydranths are specialized for defense. The main stalky body of the colony is composed of a coenosarc, which is covered by a protective perisarc. This page is a candidate to be moved to Wiktionary. ...
Asexual reproduction the simplest form of reproduction and does not involve meiosis, gamete formation, or fertilization. ...
The next generation of the life cycle begins when the medusae are released from these gonozooids, producing free swimming male and female medusae velum with gonads, a mouth, and tentacles. The physical appearance of the male and female medusae velum, including their gonads, are indistinguishable, and the sex can only be determined by observing the inside of the gonads, which will either contain sperm or eggs. The medusae reproduce sexually, releasing sperm and eggs that fertilize to form a zygote, which later morphs into a blastula, then a ciliated swimming larva called a planula. The gonad is the organ that makes gametes. ...
Tentacles can refer to the elongated flexible organs that are present in many invertebrates, and sometimes to the hairs of the leaves of some insectivorous plants. ...
Look up Sex on Wiktionary, the free dictionary A sex is one of two specimen categories of species that recombine their genetic material in order to reproduce, a process called genetic recombination. ...
Sperm is an exocrine secretion of male animal gonads that contains spermatozoa. ...
Look up Egg on Wiktionary, the free dictionary Freerange eggs in straw nest Egg has multiple meanings: The term is used synonymously with ovum, the female sex cell in animals and plants. ...
Sexual reproduction is a process of reproduction involving the merging of two gametes from the same species to produce a new organism. ...
A zygote (Greek: ζυγωτόν) is a cell that is the result of fertilization. ...
Embryogenesis is the process of cell division and cellular differentiation which leads to the development of an embryo. ...
A planula is the free-swimming, flattened, ciliated, bilaterally symmetrical larva of a hydrozoan cnidarian. ...
The planulae live in the free-swimming form for a while and eventually attach themselves to some solid surface, where they begin their asexually reproductive phase of life. Once attached to a surface, a planula quickly develops into one feeding polyp. As the polyp grows, it begins developing branches of other feeding individuals, thus forming a new generation of polyps by asexual budding.
Structure Obelia consist of two types of body plans of a polyp and medusa in their polymorphic life cycle. They are diploblastic, with two true tissue layers - an epidermis, gastrodermis, and a jelly-like mesoglea filling the area between the two true tissue layers. They carry a nerve net with no brain or ganglia. A gastrovascular cavity is present where the digestion starts and later becomes intracellular. They have incomplete digestive tracts where the food enters, digests and expelled through the same opening. During the polyp stage, the mouth is situated at the top of the body, surrounded by tentacles, whereas during the medusa stage, the mouth is situated at the distal end of the main body structure. Four gonads lie in this main body structure, or manubrium. When food is taken in through the mouth, it enters the manubrium. The food is then distributed through a canal system, consisting of four radial canals and an outer ring. Defense and the capture of prey are helped by unique stinging cells called cnidocytes that contain nematocysts, which are triggered by the cnidocil. Epidermis could refer to: In plants, the outermost layer of cells covering the leaves and young parts of a plant, see plant dermal tissue system. ...
A nerve is an enclosed, cable-like bundle of nerve fibers or axons, which includes the glia that ensheath the axons in myelin. ...
In the anatomy of animals, the brain, or encephalon, is the supervisory center of the nervous system. ...
The term ganglia may refer to: multiple clusters of neurons; see ganglion. ...
Gastrovascular cavities, as the name suggests, function in both digestion and the transport of nutrients to all parts of the body. ...
Digestion is the process whereby a biological entity processes a substance, in order to chemically convert the substance into nutrients. ...
Cnidocytes are prey-capture and defensive cells unique to animals of the phylum Cnidaria. ...
References
- B. Grzimek; Grzimek’s Animal Life Encyclopedia (Volume 1: Lower Animals); Van Nostrand Reinhold Company.
- D. George; Marine Life: An Illustrated Encyclopedia of Invertebrates in the Sea; Wiley-Interscience Publication.
- E.P Solomon, L.R Berg, and D.W Martin (editor); Biology; Thomson Learning Inc; ISBN 0-534-39175-3 (6th edition, hardcover, 2002).
- J. Moore (editor); An Introduction to the Invertebrates; Cambridge University Press
- L. Gilbertson; Zoology Laboratory Manual; The McGraw-Hill Companies, Inc; ISBN 0-07-237716-X (4th edition, 1999).
- Some taxonomic information also came from NCBI: [[1]]
Main articles: Life All organisms (viruses not included) consist of cells, which in turn, are based on a common carbon-based biochemistry. ...
External links http://www.biosci.ohiostate.edu/~eeob/eeob405/labs/cnidariageneral.html. |
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