An invertebrate is an animal Animals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and independently. All animals are also without a backbone. The group includes 95% of all animal species There are many definitions of what kind of unit a species is . A common definition is that of a group of organisms capable of interbreeding and producing fertile offspring of both genders, and separated from other such groups with which interbreeding does not (normally) happen. Other definitions may focus on similarity of DNA or morphology. Some[1] — all animals except those in the Chordate Chordates are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail. The phylum Chordata consists of three subphyla: Urochordata, represented by subphylum In life, a subphylum is a taxonomic rank intermediate between phylum and superclass. The rank of subdivision in plants and fungi is equivalent to subphylum Vertebrata Vertebrates are members of the subphylum Vertebrata, chordates with backbones or spinal columns. About 58,000 species of vertebrates have been described. Vertebrata is the largest subphylum of chordates, and contains many familiar groups of large land animals. Vertebrates comprise cyclostomes, bony fish, sharks and rays, amphibians, reptiles, (fish A fish is any aquatic vertebrate animal that is covered with scales, and equipped with two sets of paired fins and several unpaired fins. Most fish are ectothermic . Fish are abundant in most bodies of water. Fish can be found in high mountain streams (e.g., char and gudgeon) and in the deepest ocean depths (e.g., gulpers and anglerfish), reptiles Reptiles, or members of the class Reptilia, are air-breathing, generally "cold-blooded" (poikilothermic) amniotes whose skin is usually covered in scales or scutes. They are tetrapods (either having four limbs or being descended from four-limbed ancestors) and lay amniotic eggs, in which the embryo is surrounded by a membrane called the, amphibians Amphibians , such as frogs, toads, salamanders, newts, and caecilians, are ectothermic (or cold-blooded) animals that either metamorphose from a juvenile water-breathing form, to an adult air-breathing form, or paedomorph and retain some juvenile characteristics. Mudpuppies and waterdogs are good examples of paedomorphic species. Though amphibians, birds Birds are winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. There are around 10,000 living species, making them the most numerous tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the 5 cm (2 in) Bee Hummingbird to the 3 m (10 ft) Ostrich, and mammals Mammals are a class of vertebrate, air-breathing animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair and/or fur, three middle ear bones used in hearing, and a neocortex region in the brain).
Carolus Linnaeus Carl Linnaeus (Latinized as Carolus Linnaeus, also known after his ennoblement as Carl von Linné , 23 May [O.S. 12 May] 1707 – 10 January 1778) was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the' Systema Naturae The book Systema Naturae was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735. Its full title is Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis or translated: "System of nature divided these animals into only two groups, the Insecta Insects are a class within the arthropods that have a chitinous exoskeleton, a three-part body (head, thorax, and abdomen), three pairs of jointed legs, compound eyes, and two antennae. They are among the most diverse group of animals on the planet and include more than a million described species and represent more than half of all known living and the now-obsolete vermes Vermes is an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals. In Linnaeus system the group had the rank of class, occupying the 6th (and last) slot of his animal systematics. The class was divided into the following orders: (worms The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals. Currently it is used to describe many different distantly-related animals which have a long cylindrical body and no legs). Jean-Baptiste Lamarck Jean-Baptiste Pierre Antoine de Monet, Chevalier de la Marck , often just known as 'Lamarck', was a French soldier, naturalist, academic and an early proponent of the idea that evolution occurred and proceeded in accordance with natural laws, who was appointed to the position of "Curator of Insecta and Vermes" at the Muséum National d'Histoire Naturelle The museum was formally founded on 10 June 1793, during the French Revolution. Its origins lie, however, in the Jardin royal des plantes médicinales created by King Louis XIII in 1635, which was directed and run by the royal physicians. The royal proclamation of the boy-king Louis XV on 31 March 1718, however, removed the medical function, in 1793, both coined the term "invertebrate" to describe such and divided the original two groups into ten, by splitting off Arachnida Arachnids are a class of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek word ἀράχνη (aráchnē), meaning "spider" and Crustacea Crustaceans are a very large group of arthropods, usually treated as a subphylum . The group comprises almost 52,000 described species , although the number of undescribed species may be 10–100 times higher . They include various familiar animals, such as crabs, lobsters, crayfish, shrimp, krill and barnacles. The majority of them are aquatic, from the Linnean Insecta, and Mollusca Molluscs[note 1] belong to the animal phylum Mollusca. There are around 93,000 recognized extant species, making it the largest marine phylum containing about 23% of named marine organisms. Representatives live in marine, freshwater, and terrestrial habitats. Molluscs are highly diverse: in size; in anatomical structure; in behaviour and in, Annelida The annelids, collectively called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches. They are found in marine environments from tidal zones to hydrothermal vents, in freshwater, and in moist terrestrial environments. Although most textbooks still use the traditional, Cirripedia A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have two nektonic larval stages. Around 1,220 barnacle, Radiata The Radiata are the radially symmetric animals of the Eumetazoa subregnum. The term Radiata has had various meanings in the history of classification. It has been applied to the echinoderms, although the echinoderms are members of the Bilateria, because they exhibit bilateral symmetry in their developing stages, Coelenterata Coelenterata is an obsolete long term encompassing two animal phyla, the Ctenophora and the Cnidaria (coral animals, true jellies, sea anemones, sea pens, and their allies). The name comes from the Greek "koilos" ("full bellied"), referring to the hollow body cavity common to these two phyla. They have very simple tissue and Infusoria Infusoria is a collective term for minute aquatic creatures like ciliates, euglenoids, protozoa, and unicellular algae that exist in freshwater ponds. In modern formal classifications the term is considered obsolete; and the microorganisms previously included in the Infusoria are mostly assigned to the Kingdom Protista from the Linnean Vermes. They are now classified into over 30 phyla In biology, a phylum [note 1] is a taxonomic rank below Kingdom and above Class. "Phylum" is equivalent to the botanical term division, from simple organisms such as sea sponges Sponges are animals of the phylum Porifera . Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells. While all animals have unspecialized cells that can transform into specialized cells, sponges are unique in having some specialized cells that can transform into other types, often migrating between the main cell and flatworms The flatworms, known in scientific literature as Platyhelminthes or Plathelminthes (from the Greek πλατύ, platy, meaning "flat" and ἕλμινς , helminth-, meaning worm) are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrate animals. Unlike other bilaterians they have no body cavity, and no to complex animals such as arthropods An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the Phylum Arthropoda (from Greek ἄρθρον arthron, "joint", and ποδός podos "foot", which together mean "jointed feet"), and include the insects, arachnids, crustaceans, and and molluscs Molluscs[note 1] belong to the animal phylum Mollusca. There are around 93,000 recognized extant species, making it the largest marine phylum containing about 23% of named marine organisms. Representatives live in marine, freshwater, and terrestrial habitats. Molluscs are highly diverse: in size; in anatomical structure; in behaviour and in.
Invertebrates form a paraphyletic In phylogenetics, a group of organisms is said to be paraphyletic if the group contains its most recent common ancestor but does not contain all the descendants of that ancestor group. (For a full list of animals considered to be invertebrates, see animal Animals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and independently. All animals are also.) All the listed phyla are invertebrates along with two of the three subphyla In life, a subphylum is a taxonomic rank intermediate between phylum and superclass. The rank of subdivision in plants and fungi is equivalent to subphylum in Phylum Chordata Chordates are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail. The phylum Chordata consists of three subphyla: Urochordata, represented by: Urochordata Tunicates, also known as urochordates, are members of the subphylum Tunicata or Urochordata, a group of underwater saclike filter feeders with incurrent and excurrent siphons that is classified within the phylum Chordata. While most tunicates live on the ocean floor and are commonly known as sea squirts and sea pork, others – such as salps, and Cephalochordata. These two, plus all the other known invertebrates, have only one cluster of Hox genes Hox genes are a group of related genes that specify the anterior-posterior axis and segment identity of metazoan organisms during early embryonic development. These genes are critical for the proper number and placement of embryonic segment structures, while the vertebrates have duplicated their original cluster more than once.
Within paleozoology Paleozoology, also spelled as palaeozoology , is the branch of paleontology or paleobiology dealing with the recovery and identification of multicellular animal remains from geological (or even archeological) contexts, and the use of these fossils in the reconstruction of prehistoric environments and ancient ecosystems and paleobiology Paleobiology is a growing and comparatively new discipline which combines the methods and findings of the natural science biology with the methods and findings of the earth science paleontology. It is occasionally referred to as "geobiology.", invertebrates big and small are often studied within the fossil Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record. The study of fossils across geological time, how discipline called invertebrate paleontology Invertebrate paleontology is sometimes described as Invertebrate paleozoology and/or Invertebrate paleobiology. Whether it is considered to be a subfield of paleontology, paleozoology, and/or paleobiology, this discipline is the scientific study of prehistoric invertebrates by analyzing invertebrate fossils in the geologic record.
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Phyla and common examples
The fossil coral Cladocora from the Pliocene The Pliocene epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present of Cyprus Cyprus , officially the Republic of Cyprus (Greek: Κυπριακή Δημοκρατία, Kypriakī́ Dīmokratía, [kʲipɾiaˈkʲi ðimo̞kɾaˈtia]; Turkish: Kıbrıs Cumhuriyeti), is a Eurasian island country in the Eastern Mediterranean, south of Turkey and west of Syria and Lebanon. It is the third largest island in the Mediterranean Sea and.- Arthropoda An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the Phylum Arthropoda (from Greek ἄρθρον arthron, "joint", and ποδός podos "foot", which together mean "jointed feet"), and include the insects, arachnids, crustaceans, and — insects Insects are a class within the arthropods that have a chitinous exoskeleton, a three-part body (head, thorax, and abdomen), three pairs of jointed legs, compound eyes, and two antennae. They are among the most diverse group of animals on the planet and include more than a million described species and represent more than half of all known living, arachnids Arachnids are a class of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek word ἀράχνη (aráchnē), meaning "spider", crustaceans Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at 0.1 mm (0.004 in), to the Japanese spider crab with a leg span of up to 14 ft (4.3 m) and a mass
- Nematoda The "roundworms" or "nematodes" are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of described and undescribed roundworms — round worms The "roundworms" or "nematodes" are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of described and undescribed roundworms
- Mollusca Molluscs[note 1] belong to the animal phylum Mollusca. There are around 93,000 recognized extant species, making it the largest marine phylum containing about 23% of named marine organisms. Representatives live in marine, freshwater, and terrestrial habitats. Molluscs are highly diverse: in size; in anatomical structure; in behaviour and in — squid Squid are marine cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two longer tentacles, snails, bivalves
- Annelida — segmented worms (earthworms, leeches, polychaetes)
- Nemertea — ribbon worms
- Platyhelminthes — flat worms
- Rotifera
- Acoelomorpha
- Ctenophora — Comb jellies
- Cnidaria — jellyfishes, corals, sea anemones, hydras
- Porifera — sponges
- Echinoderms - starfishes, sea urchin
See also
References
Further reading
- Hyman, L. H. 1940. The Invertebrates (6 volumes) New York : McGraw-Hill. A classic work.
- Anderson, D. T. (Ed.). (2001). Invertebrate zoology (2nd ed.). Oxford: Oxford University Press.
- Brusca, R. C., & Brusca, G. J. (2003). Invertebrates (2nd ed.). Sunderland, Mass. : Sinauer Associates.
- Miller, S.A., & Harley, J.P. (1996). Zoology (4th ed.). Boston: WCB/McGraw-Hill.
- Pechenik, Jan A. (2005). Biology of the invertebrates. Boston: McGraw-Hill, Higher Education. pp. 590 pp. ISBN 0072348992.
- Ruppert, E. E., Fox, R. S., & Barnes, R. D. (2004). Invertebrate zoology: a functional evolutionary approach. Belmont, CA: Thomas-Brooks/Cole.
External links
- A. R. Maggenti & S. Gardner (2005). Online Dictionary of Invertebrate Zoology. http://digitalcommons.unl.edu/onlinedictinvertzoology/.
- Support for endangered invertebrates
- African Invertebrates
Categories: Animals | Paleontology | Zoology
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Q. What is invertebrate and how do they differ from other animals?
Asked by jaco W - Thu May 10 07:53:48 2007 - - 6 Answers - 0 Comments
A. Of the million or more animal species in the world, more than 98% are invertebrates. Invertebrates don't have an internal skeleton made of bone. Many invertebrates have a fluid-filled, hydrostatic skeleton, like the jelly fish or worm. Others have a hard outer shell, like insects and crustaceans. There are many types of invertebrates. The most common invertebrates include the protozoa, annelids, echinoderms, mollusks and arthropods.
Answered by Curiosity - Thu May 10 07:57:02 2007
