invertebrate adj : lacking a backbone or spinal column; "worms are an example of invertebrate animals" [ant: vertebrate] n : any animal lacking a backbone or notochord; the term is not used as a scientific classification
animal without backbone
- Lacking a backbone.
- Italian: invertebrato
An invertebrate is an animal lacking a vertebral column. The group includes 97% of all animal species — all animals except those in the Chordate subphylum Vertebrata (fish, reptiles, amphibians, birds and mammals).
Carolus Linnaeus' Systema Naturae divided these animals into only two groups, the Insecta and the now-obsolete vermes (worms). Jean-Baptiste Lamarck, who was appointed to the position of "Curator of Insecta and Vermes" at the Muséum National d'Histoire Naturelle in 1793, both coined the term "invertebrate" to describe such and divided the original two groups into ten, by splitting off Arachnida and Crustacea from the Linnean Insecta, and Mollusca, Annelida, Cirripedia, Radiata, Coelenterata and Infusoria from the Linnean Vermes. They are now classified into over 30 phyla, from simple organisms such as sea sponges and flatworms to complex animals such as anglican bishops, arthropods and molluscs.
Invertebrates form a paraphyletic group. (For a full list of animals considered to be invertebrates, see animal.) All the listed phyla are invertebrates along with two of the three subphyla in Phylum Chordata: Urochordata and Cephalochordata. These two, plus all the other known invertebrates, have only one cluster of Hox genes, while the vertebrates have duplicated their original cluster more than once.
Within paleozoology and paleobiology, invertebrates big and small are often studied within the fossil discipline called invertebrate paleontology.
Phyla and common examples
- Annelida — segmented worms (earthworms, leeches, polychaetes)
- Arthropoda — insects, arachnids, crustaceans
- Cnidaria — jellyfishes, corals, sea anemones, hydras
- Echinodermata — starfish, sea urchins, sea cucumbers
- Mollusca — squid, snails, bivalves
- Nematoda — roundworms
- Nematomorpha — horsehair worms or gordian worms
- Platyhelminthes — flatworms
- Porifera — sponges
MacroinvertebratesThe term macroinvertebrates is traditionally used to refer to aquatic invertebrates including insects (e.g. larval Ephemeroptera and Trichoptera), crustaceans (e.g. amphipods), molluscs (e.g. aquatic snails) and worms (e.g. Platyhelminthes), which inhabit a river channel, pond, lake, wetland or ocean. Historically, their abundance and diversity have been used as an indicator of ecosystem health and of local biodiversity. They are a key component of the food chain.
Most indices that are used to determine water quality rank the various forms of benthic macroinvertebrates with respect to pollution sensitivity. The presence of pollution sensitive macroinvertebrates indicates that the body of water is healthy. Alternatively, the excessive presence of pollution tolerant macroinvertebrates indicates poor water quality. Ideally, a healthy body of water will hold an abundant and diverse macroinvertebrate population.
The macroinvertebrates traditionally seen as being pollution sensitive include: mayflies (Ephemeroptera), caddisflies (trichoptera), and stoneflies (Plecoptera). The macroinvertebrates that have been traditionally considered pollution tolerant include: aquatic worms (Oligocheata), leeches (Hirudinea) and non-biting midges or commonly known as "blood worms" (Chironomidae).
Flow, food, habitat and water quality are the primary determinants of macroinvertebrate abundance and diversity. Food sources include phytoplankton, biofilms (i.e. the layers of bacteria or other micro-organisms that cover submerged surfaces) and terrestrial organic material (e.g. leaves) that enter the water from the riparian vegetation. Major predation occurs from other macroinvertebrates and fish. Key habitats for macroinvertebrates are the benthic sediments, aquatic vegetation and woody debris. Salinity, temperature, dissolved oxygen, and turbidity have a significant impact.
There are many different kinds of arthropods. but they mainly have the structure of a segmented body and jointed legs.
- Life Cycle of Macroinvertebrates
Macroinvertebrates go through a life cycle in usually one season or less. They go through complete or incomplete metamorphosis. Learn more about the stages at this website.
- 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.
- Biology of the invertebrates
- Ruppert, E. E., Fox, R. S., & Barnes, R. D. (2004). Invertebrate zoology: a functional evolutionary approach. Belmont, CA: Thomas-Brooks/Cole.
- Online Dictionary of Invertebrate Zoology
- Support for endangered invertebrates
invertebrate in Arabic: لافقاريات
invertebrate in Bosnian: Beskičmenjaci
invertebrate in Bulgarian: Безгръбначни
invertebrate in Catalan: Invertebrat
invertebrate in Czech: Bezobratlí
invertebrate in Welsh: Infertebrat
invertebrate in Danish: Hvirvelløse dyr
invertebrate in German: Wirbellose
invertebrate in Estonian: Selgrootud
invertebrate in Spanish: Invertebrado
invertebrate in Esperanto: Senvertebruloj
invertebrate in Persian: بیمهرگان
invertebrate in French: Invertébré
invertebrate in Korean: 무척추동물
invertebrate in Croatian: Beskralješnjaci
invertebrate in Indonesian: Invertebrata
invertebrate in Icelandic: Hryggleysingjar
invertebrate in Italian: Invertebrata
invertebrate in Hebrew: חסרי חוליות
invertebrate in Georgian: უხერხემლოები
invertebrate in Lithuanian: Bestuburiai
invertebrate in Lingala: Nyama ya mikúwa tɛ̂
invertebrate in Malay (macrolanguage): Invertebrat
invertebrate in Dutch: Ongewervelden
invertebrate in Japanese: 無脊椎動物
invertebrate in Norwegian: Virvelløse dyr
invertebrate in Norwegian Nynorsk: Virvellause dyr
invertebrate in Narom: Bête sans héthèque
invertebrate in Occitan (post 1500): Invertebrata
invertebrate in Polish: Bezkręgowce
invertebrate in Portuguese: Invertebrado
invertebrate in Russian: Беспозвоночные
invertebrate in Simple English: Invertebrate
invertebrate in Slovak: Bezstavovce
invertebrate in Slovenian: Nevretenčarji
invertebrate in Serbian: Бескичмењаци
invertebrate in Finnish: Selkärangattomat
invertebrate in Swedish: Ryggradslösa djur
invertebrate in Tagalog: Invertebrata
invertebrate in Thai: สัตว์ไม่มีกระดูกสันหลัง
invertebrate in Turkish: Omurgasızlar
invertebrate in Ukrainian: Безхребетні
invertebrate in Walloon: Incronzoxhî
invertebrate in Chinese: 无脊椎动物
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