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The animals portal

""Animal diversity October 2007 for thumbnail.jpg

"Animals are "multicellular, "eukaryotic "organisms of the "kingdom Animalia (also called Metazoa). Their "body plan eventually becomes fixed as they "develop, although some undergo a process of "metamorphosis later on in their "lives. Most animals are "motile, meaning they can move spontaneously and independently. Most all animals must ingest other organisms or their products for "sustenance, with the exception of those that form "symbiotic relationships with photosynthetic organisms.

Most known animal "phyla appeared in the fossil record as marine species during the "Cambrian explosion, about 542 million years ago. Animals are divided into various sub-groups, some of which are: "vertebrates ("birds, "mammals, "amphibians, "reptiles, "fish); "mollusks ("clams, "oysters, "octopuses, "squid, "snails); "arthropods ("millipedes, "centipedes, "insects, "spiders, "scorpions, "crabs, "lobsters, "shrimp); "annelids ("earthworms, "leeches); "sponges; and "jellyfish.

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""Barentsia discreta

"Entoprocta is a "phylum of mostly "sessile aquatic animals, ranging from 0.1 to 7 millimetres (0.0039 to 0.28 in) long. Mature individuals are "goblet-shaped, on relatively long stalks. They have a "crown" of solid tentacles whose cilia generate water currents that "draw food particles towards the mouth, and both the mouth and anus lie inside the "crown". The superficially similar "Bryozoa (Ectoprocta) have the anus outside a "crown" of hollow tentacles. Most "families of entoprocts are colonial, and all but 2 of the 150 species are marine. A few solitary species can move slowly. Some species eject unfertilized "ova into the water while others keep their ova in brood chambers until they hatch, and some of these species use "placenta-like organs to nourish the developing eggs. After hatching, the "larvae swim for a short time and then settle on a surface. There they "metamorphose, and the larval gut generally rotates by up to 180°, so that the mouth and anus face upwards. Both colonial and solitary species also reproduce by "cloning — solitary species grow clones in the space between the tentacles and then release them when developed, while colonial ones produce new members from the stalks or from corridor-like "stolons. Some species of "nudibranchs ("sea slugs") and "turbellarian "flatworms prey on entoprocts. A few entoproct species have been found living in close association with other animals. It is uncertain whether any are invasive species.

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""Coral
Credit: "Toby Hudson

"Corals are "marine invertebrates that typically live in compact "colonies of many identical individual "polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in length. Corals are major contributors to the physical structure of the "coral reefs such as the "Great Barrier Reef, where this photograph was taken. Coral reefs are under threat globally from "ocean acidification and "climate change.

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When the fox dies, fowls do not mourn.

—Anonymous

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""A colour print of platypuses from 1863
The "platypus (Ornithorhynchus anatinus) is a "semiaquatic egg-laying "mammal "endemic to "eastern Australia, including "Tasmania. Together with the four species of "echidna, it is one of the five extant species of "monotremes, the only mammals that lay "eggs instead of giving birth. The animal is the sole living representative of its "family ("Ornithorhynchidae) and "genus (Ornithorhynchus), though a number of "related species have been found in the fossil record. The unusual appearance of this egg-laying, "duck-billed, "beaver-tailed, "otter-footed mammal baffled European naturalists when they first encountered it, with some considering it an elaborate hoax. It is one of the few "venomous mammals, the male platypus having a "spur on the hind foot that delivers a "venom capable of causing severe pain to humans. Until the early 20th century, it was hunted for its fur, but it is now protected throughout its range. Although captive breeding programs have had only limited success and the platypus is vulnerable to the effects of pollution, it is not under any immediate threat.

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