The Animals Portal
Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres (110 ft) and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal often refers only to non-human animals. The study of non-human animals is known as zoology.
Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan. The Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes, arthropods, and molluscs—and the deuterostomes, containing the echinoderms and chordates (including the vertebrates). Life forms interpreted as early animals were present in the Ediacaran biota of the late Precambrian. Many modern animal phyla became clearly established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified; these may have arisen from a single common ancestor that lived 650 million years ago.
Aristotle divided animals into those with blood and those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa (now synonymous with Animalia) and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa.
Humans make use of many other animal species for food, including meat, milk, and eggs; for materials, such as leather and wool; as pets; and as working animals for power and transport. Dogs have been used in hunting, while many terrestrial and aquatic animals are hunted for sport. Non-human animals have appeared in art from the earliest times and are featured in mythology and religion.
Meerkat Manor is a British television programme produced by Oxford Scientific Films for Animal Planet International that ran for four series between September 2005 and August 2008. Blending more traditional animal documentary style footage with dramatic narration, the series told the story of the Whiskers, one of more than a dozen families of meerkats in the Kalahari Desert being studied as part of the Kalahari Meerkat Project, a long-term field study into the ecological causes and evolutionary consequences of the cooperative nature of meerkats. With the success of the programme in the UK, Animal Planet started broadcasting it on its national channels in Australia, Canada, and the US. It has since been rebroadcast in more than 160 other countries. Although the show faced criticism from viewers for not intervening when a meerkat was injured and faced death, as a whole Meerkat Manor enjoyed considerable success, and its experimental format broke new ground in animal documentary filming techniques. It was nominated for two Primetime Emmy Awards in 2007, and was a winner at the 2006 Omni Awards and at the 2006 and 2007 New York Festivals Award Galas.
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The Tasmanian Devil
is a carnivorous marsupial
found exclusively on the Australian
island of Tasmania
. At the size of a small dog
, but stocky and muscular, the Tasmanian Devil is the largest carnivorous marsupial in the world. The devil is characterised by its black fur, offensive odour when stressed, extremely loud and disturbing screech, and vicious temperament when feeding. Known to hunt, as well as to scavenge carrion
, communal eating is one of the few social activities in which the usually solitary devil participates. The Tasmanian Devil became extinct
on the Australian mainland about 400 years prior to European settlement
. The people of Tasmania saw devils as a threat to livestock
and hunted them until 1941
, when the animals were officially protected. Since the late 1990s devil facial tumour disease
has reduced the devil population significantly and threatens the survival of the species. The impact of the disease on devil population may lead to listing of the devil as an endangered species
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