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Related to Invertebrates: Arthropods



a large group of animals lacking spines.

Invertebrates include Protozoa, sponges, Coelenterata, lower worms, mollusks, Articulata, echinoderms, and several other phyla—a total of 16 phyla of invertebrates. The division of animals into invertebrates and vertebrates was introduced in 1801 by the French biologist J. B. Lamarck. This division has no taxonomic significance. However, the term “invertebrates” is used descriptively in scientific and, especially, educational literature.

Invertebrates include the overwhelming majority of the animals that inhabit the earth. About 1.26 million species of invertebrates are known, while there is a total of 45,000 species of vertebrates. Insects are the most numerous invertebrates: more than 1 million species are known. (In reality, there are probably no fewer than 2 million species of insects.) Other groups of invertebrates with the number of species are Protozoa, 25,000 species; sponges, 5,000; Coelenterata, 9,000; lower worms, 20,000; mollusks, 107,000; and Articulata (excluding insects) no fewer than 79,000 species. Obviously, the number of species of invertebrates existing in nature is much higher. Every year several thousand previously unknown species are described.

Invertebrates are prevalent everywhere—in fresh water, in the seas and oceans, on land, and in the soil. Many are animal and plant parasites. The role of invertebrates in nature is very great. Solid remains of invertebrates that lived in previous geological eras are part of the composition of various sedimentary rocks. Sometimes these remains constitute the bulk of the rock. (For example, limestones consist almost entirely of the skeletons of extinct invertebrates —Foraminifera, corals, Bryozoa, mollusks, and others.)

The importance of invertebrates for mankind is great and varied. Many invertebrates or their products serve as food for humans (bees’ honey, crustaceans, mollusks, and others) or various game animals, birds, and fish. The products of the life activity of certain invertebrates have economic and industrial value (beeswax, silk threads from silkworms, shellac from Coccidia, dyes, such as sepia from cuttlefish, pearls and shells of mollusks, and skeletons of coral polyps). In a number of instances, invertebrates are used to fight harmful animals; that is, parasites and predators destroy the harmful animals. (This is the biological method of fighting pests that injure useful plants and animals.) In geology, the study of the remains of fossilized invertebrates is particularly valuable in determining the age of sedimentary rocks.

In addition to the useful invertebrates, there are many harmful ones, including animals that are carriers of infectious and parasitic pathogens; intermediate hosts of parasitic worms and carriers of communicable diseases; poisonous animals; pests that attack grain, grain products, and agricultural plants; and forest pests.


Zhivotnyi mir SSSR, vol. 1. Moscow-Leningrad, 1936.
Abrikosov, G. G. “Znachenie bespozvonochnykh zhivotnykh dlia narodnogo khoziaistva.” In Kurs zoologii, 4th ed., vol. 1. Moscow, 1949.
Ivanov, A. V. Promyslovye vodnye bespozvonochnye. Moscow, 1955.
Dogel’, V. A. Zoologiia bespozvonochnykh, 5th ed. Moscow, 1959.
Zhizn’ zhivotnykh, vols. 1–3. Moscow, 1968–69.


References in periodicals archive ?
Albany was also a world-renowned natural scientist who conducted much of his research on invertebrates including nudibranchs and brachiopods.
The researchers, from Bangor University and the University of Exeter, used a raft in the Menai Strait to monitor how artificial light at night can affect the settlement of marine invertebrates into new habitats.
About The Xerces Society for Invertebrate Conservation Protecting the Life that Sustains Us The Xerces Society for Invertebrate Conservation is a nonprofit organization that protects wildlife through the conservation of invertebrates and their habitat.
The public is likely aware of the value of coral reefs in terms of the impact on tourism and fishing, however, the potential of microbes living within coral reef invertebrates to produce life-saving medicines and other bioproducts is likely not well understood.
In liquid form it will eventually enter the water course and on reaching the river kill all invertebrates for miles.
Washington, July 25 ( ANI ): A new study has revealed that invertebrate numbers have decreased by 45 percent on average over a 35 year period in which the human population doubled.
Inputs of terrestrial invertebrates from the riparian zone to streams have long been recognized as an important flux of energy from one ecosystem to the other.
Miller (Stream Ecologist, Wisconsin Department of Natural Resources), with environmental scientists Katie Songer, and Ron Dolen, "Field Guide to Wisconsin Streams: Plants, Fishes, Invertebrates, Amphibians, and Reptiles" is a beautifully and profusely illustrated, 336 page compendium providing a superbly organized and presented identification manual for more than 130 plants and 120 fish common to Wisconsin, as well as 8 crayfishes, 50 mussels, 10 amphibians, 17 reptiles, 70 families of insects, and a number of Wisconsin's other commonly found invertebrates.
Volunteers will get to examine invertebrates collected from the river with a microscope before heading to the river and netting their own creatures to identify.
Other studies have provided anecdotal observations of Golden-fronted Woodpecker food items which consisted of a variety of invertebrates (adult and larval forms), fruits, nuts, and grains (Husak and Maxwell 1998).