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, 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 animals 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 study of animals is called zoology.
Most living animal species are classified 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, to which echinoderms and chordates (including the vertebrates) belong. Life forms interpreted as early animals were present in the Ediacaran biota of the late Precambrian. Most modern animal phyla became clearly established in the fossil record as marine species during the Cambrian explosion around 542 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 the late-1800s, 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. Animals have appeared in art from the earliest times and are featured in mythology and religion.
Carl Linnaeus ( 23 May 1707 – 10 January 1778) was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern biological naming scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology. Linnaeus was born in the countryside of Småland, in southern Sweden. He received most of his higher education at Uppsala University, and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and also published a first edition of his Systema Naturae in the Netherlands. He then returned to Sweden, where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and '60s, he continued to collect and classify animals, plants, and minerals, and published several volumes. At the time of his death, he was one of the most acclaimed scientists in Europe.
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When the fox dies, fowls do not mourn.
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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
Did you know...
- ...that Carolus Linnaeus' (portrait pictured) research on classification led to objections and rebukes from religious authorities?
- ...that Lampreys are called "nine-eyed eels" (i.e., per side) from a counting of their seven external gill slits on a side with one eye and the nostril?