The annelids ( also called Ringed Worm ), collectively called Annelida (from French annelés "ringed ones", ultimately from Latin anellus "little ring"[1]), 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 division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species, research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of polychaetes. Annelids are considered members of the Lophotrochozoa, a "super-phylum" of protostomes that also includes molluscs, brachiopods, flatworms and nemerteans.
The basic annelid form consists of multiple segments, each of which has the same sets of organs and, in most polychaetes, a pair of parapodia that many species use for locomotion. Septa separate the segments of many species, but are poorly-defined or absent in some, and Echiura and Sipuncula show no obvious signs of segmentation. In species with well-developed septa, the blood circulates entirely within blood vessels, and the vessels in segments near the front ends of these species are often built up with muscles to act as hearts. The septa of these species also enable them to change the shapes of individual segments, which facilitates movement by peristalsis ("ripples" that pass along the body) or by undulations that improve the effectiveness of the parapodia. In species with incomplete septa or none, the blood circulates through the main body cavity without any kind of pump, and there is a wide range of locomotory techniques - some burrowing species turn their pharynges inside out to drag themselves through the sediment.
Although many species can reproduce asexually and use similar mechanisms to regenerate after severe injuries, sexual reproduction is the normal method in species whose reproduction has been studied. The minority of living polychaetes whose reproduction and lifecycles are known produce trochophore larvae, which live as plankton and then sink and metamorphose into miniature adults. Oligochaetes are full hermaphrodites and produce a ring-like cocoon round their bodies, in which the eggs and hatchlings are nourished until they are ready to emerge.
Earthworms support terrestrial food chains both as prey and by aerating and enriching soil. The burrowing of marine polychaetes, which may constitute up to a third of all species in near-shore environments, encourages the development of ecosystems by enabling water and oxygen to penetrate the sea floor. In addition to improving soil fertility, annelids serve humans as food and as bait. Scientists observe annelids to monitor the quality of marine and fresh water. Although blood-letting is no longer in favor with doctors, some leech species are regarded as endangered species because they have been over-harvested for this purpose in the last few centuries. Ragworms' jaws are now being studied by engineers as they offer an exceptional combination of lightness and strength.
Since annelids are soft-bodied, their fossils are rare - mostly jaws and the mineralized tubes that some of the species secreted. Although some late Ediacaran fossils may represent annelids, the oldest known fossil that is identified with confidence comes from about 518 million years ago in the early Cambrian period. Fossils of most modern mobile polychaete groups appeared by the end of the Carboniferous, about 299 million years ago. Scientists disagree about whether some body fossils from the mid Ordovician, about 472 to 461 million years ago, are the remains of oligochaetes, and the earliest certain fossils of the group appear in the Tertiary period, which began 65 million years ago.
why nephrostome are not in the same septa where its own nephredia are located in earthworm
The Liquid Waste Is Liberated From The Skin. That Is Why The Earthworm Is Moist
Yes of course they do
it evaporates from its skin
Urea and Ammonia- Dev Mehta
Cast
they dispose waste of the earthworms.
Pair of nephridia in earthworm's segments excretes waste through pores in the skin, removing waste from the blood and body fluids.
transport nutrition and waste
the brain is essential for the movement of the earthworm. If the brain of the earthworm is removed, the earthworm will move continuously without stop
Yes, an earthworm is a decomposer.
the kidney, which is part of the excretory system.
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The same reason as humans do. They have to get rid of their liquid waste.
That would be the urinary bladder.
the kidney rid of because the muscles are living in our body that's why the kidney rid of
dirt
they dispose waste of the earthworms.
The intestines help carry the earthworm's waste to the anus, where it is expelled from the worm.
through their skin
they are squished
diffusion through its skin
Monkeys get rid of their wastes in the same way that humans get rid of waste. Monkeys have a digestive tract and excretory system that allow the animal to remove liquid waste through urination and solid waste through defecation.