Sabtu, 14 Juli 2012

Penguin


 

The Biggest Animals Kingdom and in The World | Penguin | The etymology of the word "penguin" is still debated.  Some dictionaries propose a derivation from Welsh pen "head" and Gwyn, "white", including the Oxford English Dictionary, Dictionary American Heritage Dictionary and Merriam-Webster century, arguing that the name was originally applied to Auk, and because it was found at White Head Island (Pen Gwyn Welsh) in Newfoundland, or because they are white circles around the eyes had. In Dutch the word penguin is an alternative to the "Fat Cat" and give this bird got its name from its appearance felt.


Moreover, they restrict the phylogenetic taxon Sphenisciformes of taxa of flying, and set equal to the phylogenetic taxon PANSPHENISCIFORMES Sphenisciformes Linnean taxon, including any flying basal "proto-penguins" to discover at the end. Since no mention of penguin subfamilies to each other or the positioning of the penguins in the avian phylogeny currently resolved, is clearly fixed Linnean system here follows. The evolutionary history of penguins is well studied and is a showcase of evolutionary biogeography, although, like the bones of the penguins of a species vary greatly in size and a few good examples are known, the alpha taxonomy of many prehistoric forms late much to be desired. Some groundbreaking articles about penguin prehistory have been published since 2005, the evolution of the living genera are now considered resolved.


The basal penguins lived around the time of the Cretaceous-Paleogene extinction sometime in the (southern) New Zealand and Byrd Land, Antarctica. This genus has a distribution focused on Antarctic coasts and barely extends to some subantarctic islands today. Pygoscelis contains species with a fairly simple black-white model of the head, its distribution is intermediate, focused on the Antarctic coast, but extending somewhat "north of there.


Any lack of carotenoid color, and the first general model has a big head bands, but are unique among the penguins that live in burrows of nesting. This group probably radiated eastwards with the Antarctic Circumpolar Current outside the ancestral range of modern penguins in the Chattian (late Oligocene) of about 28 million years ago. The Megadyptes of Eudyptes clade occurs at the same latitude, although not as far north as the Galapagos Penguin), the highest diversity in the region of New Zealand, and represent a westward spread.


With habitats on the coasts of Antarctica in the fall of Priabonian more hospitable conditions for most of the penguins in the subantarctic regions rather than in Antarctica itself. The emergence of most species of subantarctic penguins almost certainly caused by this series of Neogene climate change. Penguin ancestry beyond Waimanu remains unknown and not easily solved by molecular or morphological analysis. What seems clear that penguins belong to a clade of Neoaves (except birds and birds that live paleognaths), that what is called "higher waterbirds" to distinguish them from the oldest waterfowl covers.


Some think that the penguin plotopterids similar (usually considered relatives of anhingas and cormorants) may actually have a sister group of penguins, and penguins can eventually shared a common ancestor with PELECANIFORMES and therefore should have been included in this order, or that the plotopterids not closer to the other pelecaniforms as commonly used, where the distribution of traditional PELECANIFORMES would three is Penguins are superbly adapted to aquatic organisms. In the water, but penguins are astonishingly agile. Swim of the penguins is very similar to bird in the air. The layer of air also helps to isolate the birds in cold water. On land, penguins use their tails and wings to the balance for their upright position to maintain. All penguins are counter shaded to camouflage, have black backs and wings with white fronts.


Larger penguins can dive deep in case of emergency. The diving of the great emperor penguin recorded to a depth of 565 meters (1870 feet) to reach up to 22 minutes. Or Penguins waddle on their feet or slide on his belly through the snow, a movement called "slips", which saves energy while driving fast. Penguins have an average hearing for birds that are used by parents and chicks with one another in crowded colonies found. The Emperor penguin (the largest penguin) is the largest body mass of all penguins, which further reduces relative surface area and heat loss. The Auk of the Northern Hemisphere, now extinct, was superficially similar to penguins, and the word "penguin" was originally used for bird who, centuries ago. They are not related to the penguins at all, but are an example of convergent evolution.

 

Although all penguin species are from the southern hemisphere, are not found only in cold climates such as Antarctica. In reality, only a few species of penguin actually live so far south. At least 10 species live in the temperate zone, one of the Galapagos penguin, lives in the north to the Galapagos Islands, but this is made possible only by the cold and rich waters of the Antarctic Humboldt current around these islands. Several authors have suggested that penguins are a good example of the Bergmann rule, body with large populations living at higher latitudes than smaller populations body.


Large populations of penguins are in Antarctica, Argentina, Australia, Chile, New Zealand and South Africa Penguins breed for the most part in large colonies, with the exception of the species yellow eyes and Fiordland, these colonies range in size from a minimum of 100 pairs of Gentoo penguins, to several hundred thousand in the case of King, Macaroni and Chinstrap Penguins. Living in colonies results in a high level of social interaction between birds, which led to an extensive repertoire of visual and vocal expressions in all species of penguins. Penguins form monogamous pairs for a breeding season, even if the same pair recouples speed varies greatly. Most penguins lay two eggs in a clutch, even if the two larger species, the emperor and king penguins, there was only one. With the exception of the Emperor Penguins, where the man does everything, all penguins share the incubation duties This incubation shifts can last for days and even weeks, as a member of the couple to feed the sea.

Penguins usually only one brood to offer, the exception is the little penguin, by two or three broods in a season to increase. Eggs penguin smaller than other species of birds than in proportion to the weight of the parent bird 52 g (2 oz), the small egg penguin 4.7% of the weight of the mothers, and 450 g (1 lb) Emperor Penguin egg is 2.3%. The shell is relatively thick between 10 and 16% of the weight of a penguin egg, presumably to reduce the risk of fracture in an unfavorable environment nesting.

When mothers lose a chick, who sometimes try to "steal" another mother's chick, usually unsuccessfully as other women in the vicinity assist the defending mother in keeping her chick in some species such as emperor penguins, the young penguins to gather in large groups called creches. Penguins seem to have no special fear of humans and have approached groups of explorers without hesitation. This is probably because the penguins have no land predators in Antarctica or the nearby offshore islands. Instead, penguins are at risk at sea from predators such as leopard seals. Generally no penguins closer than about 3 meters (10 ft) at which time they are nervous. This is also the distance that Antarctic tourists are told to avoid penguins 
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