An overview of isopoda organisms

Observe various aspects of a terrestrial isopod Conduct experiments examining the responses of isopods to various environmental factors Design and conduct an investigation of animal behavior Isopod Handling and Rearing Raise isopods in a clear shoebox or similar, the bottom should be covered with soil or sand and kept moist use a mister.

An overview of isopoda organisms

The woodlouse Oniscus asellus showing the head with eyes and antennae, carapace and relatively uniform limbs Classified within the arthropodsisopods have a chitinous exoskeleton and jointed limbs.

Their colour may vary, from grey to white, [6] or in some cases red, green, or brown. This means that the gill -like structures, which in other related groups are protected by the carapace, are instead found on specialised limbs on the abdomen.

The isopod body plan consists of a head cephalona thorax pereon with eight segments pereonitesand an abdomen pleon with six segments pleonitessome of which may be fused.

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There are two pairs of unbranched antennaethe first pair being vestigial in land-dwelling species. The eyes are compound and unstalked and the mouthparts include a pair of maxillipeds and a pair of mandibles jaws with palps segmented appendages with sensory functions and lacinia mobilis spine-like movable appendages.

In most species these are used for locomotion and are of much the same size, morphology and orientation, giving the order its name "Isopoda", from the Greek equal foot. In a few species, the front pair are modified into gnathopods with clawed, gripping terminal segments.

The pereopods are not used in respiration, as are the equivalent limbs in amphipodsbut the coxae first segments are fused to the tergites dorsal plates to form epimera side plates.

In mature females, some or all of the limbs have appendages known as oostegites which fold underneath the thorax and form a brood chamber for the eggs. In males, the gonopores genital openings are on the ventral surface of segment eight and in the females, they are in a similar position on segment six.

In males, the second pair of pleopods, and sometimes also the first, are modified for use in transferring sperm. The endopods inner branches of the pleopods are modified into structures with thin, permeable cuticles flexible outer coverings which act as gills for gas exchange.

They have a cosmopolitan distribution and over 10, species of isopod, classified into 11 suborders, have been described worldwide. About species are found in fresh water and another 5, species are the terrestrial woodlicewhich form the suborder Oniscidea.

Some members of the family Cirolanidae suck the blood of fish, and others, in the family Aegidaeconsume the blood, fins, tail and flesh and can kill the fish in the process. Members are mostly carnivorous or parasitic.

Includes the family Gnathiidaethe juveniles of which are parasitic on fishes. This suborder now includes part of the formerly recognised suborder Flabellifera.

At that time, Phreatoicideans were marine organisms with a cosmopolitan distribution. Nowadays, the members of this formerly widespread suborder form relic populations in freshwater environments in South Africa, India and Oceania, the greatest number of species being in Tasmania.

Gallery of Carcinologists: Selected Biographical Sketches Macedo, in Sexual SelectionArthropods Terrestrial arthropods comprise representatives of four major groups: There is no doubt that diversity of morphologies, behaviors, and perhaps physiological strategies can thwart generalizations.

Other primitive, short-tailed suborders include AsellotaMicrocerberideaCalabozoidea and the terrestrial Oniscidea. The long-tailed isopods have a long pleotelson and broad lateral uropods which can be used in swimming. They are much more active and can launch themselves off the seabed and swim for short distances.

The more advanced long-tailed isopods are mostly endemic to the southern hemisphere and may have radiated on the ancient supercontinent of Gondwana soon after it broke away from Laurasia million years ago. The short-tailed forms may have been driven from the shallow seas in which they lived by increased predatory pressure from marine fish, their main predators.

The development of the long-tailed forms may also have provided competition that helped force the short-tailed forms into refugia. The latter are now restricted to environments such as the deep sea, freshwater, groundwater and dry land.

Isopods in the suborder Asellota are by far the most species-rich group of deep sea isopods. This gives them little chance to disperse to new regions and may explain why so many species are endemic to restricted ranges.

Palaeos Arthropods: Crustacea: Malacostraca: Isopoda

Crawling is the primary means of locomotion, and some species bore into the seabed, the ground or timber structures. Some members of the Flabellifera can swim to a limited extent and have their front three pairs of pleopods modified for this purpose, with their respiratory structures limited to the hind pleopods.

Most terrestrial species are slow-moving and conceal themselves under objects or hide in crevices or under bark. The semi-terrestrial sea slaters Ligia spp. Food is sucked into the esophagusa process enhanced in the blood-sucking parasitic species, and passed by peristalsis into the stomach, where the material is processed and filtered.

The structure of the stomach varies, but in many species there is a dorsal groove into which indigestible material is channelled and a ventral part connected to the caeca where intracellular digestion and absorption take place.

Indigestible material passes on through the hindgut and is eliminated through the anuswhich is on the pleotelson. Only aquatic and marine species are known to be parasites or filter feeders. In marine isopods that feed on wood, cellulose is digested by enzymes secreted in the caeca.

Limnoria lignorumfor example, bores into wood and additionally feeds on the mycelia of fungi attacking the timber, thus increasing the nitrogen in its diet.Hence, contrary to terrestrial Isopoda, S. entomon has at least the neuronal substrate to perceive and process olfactory stimuli suggesting the originally marine isopod lineage had olfactory abilities comparable to that of other malacostracan crustaceans.

An overview of isopoda organisms

Lesson Plan: Chain Reaction Overview This inquiry-based lesson plan will challenge students to design and conduct scientifically valid experiments to evaluate hypotheses regarding an animal’s expected behavior in response to changes in its environment.

A collaborative effort of marine biologists, ecologists, oceanographers and glaciologists, this study provides an overview of the Antarctic region as a marine ecosystem. Emphasis is placed on the impact of ice masses on the krill, the flowering of phytoplankton and the ecophysiology of fauna.

Overview: Asellus hilgendorfii is a freshwater isopod, native to eastern Siberia, Japan, and China. It has been introduced to low salinity areas of the San Francisco Bay Estuary, in the Sacramento-San Joaquin Delta, California.

This is its only known occurrence in North America. Isopod crustaceans are among the most numerous and diverse macrofaunal taxa in the derp sea. In contrast to the situation in shallow water, the Asellota encompasses the majority of the deep-sea fauna.

Descriptions and articles about the Isopods, scientifically known as Isopoda in the Encyclopedia of Life. Includes Overview; Brief Summary; Comprehensive Des.

Isopoda - New World Encyclopedia