The Unique Australian WildlifeThe notes to the geological history of the continentBy Maria SkochilovaSchool 7Nizhny Tagil
Many countries have their own unique fauna.But Australia is mostly unusual in that
320-270 million years agoPermo-Carboniferous Age If we had observedthe Earth surface from space at that time, we would have seen quite the other picture
270-210 million years ago The end of Permian – the beginning of Trias About 275 million years ago Euroamerica and Angara made a huge landmass of Laurasia The Tethys Sea Separated Laurasia from the protocontinent of Pangaea
270-210 million years ago The end of Permian – the beginning of Trias On land the vertebrates are represented in the Triassic by amphibians and reptiles. The first true mammals, which were very small, are supposed to appear in the Late Triassic.
Triassic Period: continents and oeans of the Earth in Early Triassic time
Monotreme The egg-laying mammalians include the amphibious platypusand the terrestrial echidnas of Australia, Tasmania, and New Guinea short-beaked echidna
180 million years ago Middle Jurassic period The protocontinent supposedly covered about half the Earth and was completely surrounded by a world ocean called Panthalassa.
180 million years ago Middle Jurassic period Dinosaurs and other reptiles emerged to dominate the land, sea, and sky.The first birds and new varieties of reefbuilding and other invertebrate faunas, provided Jurassic life with added complexity.
Late Jurassic Epoch: geochronological map
100 million years agoEarly Cretaceous Period Later Pangaea began to break apart. Its segments Laurasia and Gondwanaland gradually receded, resulting in the formation of the Atlantic Ocean.
100 million years agoEarly Cretaceous PeriodTwo important groups of modern mammals evolved during the Cretaceous. Cretaceous placentals, smaller than those of present-day ones, were poised to take over the terrestrial environments as soon as the dinosaurs vanished.
100 million years agoEarly Cretaceous Period Another mammal group, the marsupials, evolved during the Cretaceous as well. This group includes the native speciesof Australia, kangaroos, koalas, and the North American opossum.
Late Cretaceous Epoch: geochronological map
70 million years agoThe end of Cretaceous Period The Late Cretaceous record is much more complete. It is known, for instance, that during the Late Cretaceous many dinosaur types lived in relationships like the present-day terrestrial mammals.
Diprotodon characterized by a wombat-like body the size of a large rhinoceros. massively constructed skeleton to support its imposing bulk. well developed teethof gnawing animals. herbivorous distantly related to kangaroos and wombats. extinct marsupial mammals existed 30 - 10,000 years ago in Australia.
45 million years agoThe beginning of Cenozoic era By that time Australasia was isolated from all other continental masses, here marsupials evolved into many diverse forms. In South America they survived alongside placentals, forming the Neotropical mammalian fauna.
Structural and behavioral parallels with placental mammals are in some cases quite striking.
There are marsupials that look remarkably like moles, shrews, squirrels, mice, dogs, and hyenas.
The koala and the kangaroo are the most well-known marsupials.
MarsupialsSpotted-tailed quoll, or native cat
Marsupials Virginia, or opossum
Marsupials Red kangaroo –Wallaby Western grey kangaroo
Marsupials Kangaroo Rat Dunnart, a marsupial mouse
MarsupialsTasmanian Devil Wombat
Marsupials The niches that marsupials fill are closely associated with structure. The diets of marsupials are as varied as the niches they occupy.
The burrowing species have powerful foreclaws with which they can tunnel into the ground for food and for shelter The gliders have a membrane along either flank,attached to the forelegs and hind legs, that enables the animals to glide down from a high perch
Cenozoic Era: faunal migration routes and barriers
The earliest isolation of Australia from all the other continents made its fauna unique
Literature Т. Клементьева, Дж. Шэннон Happy English-3 – Обнинск: Титул, 2005Д. Эттенборо Живая природа – М.: Мир книги, 2001Britannica 2007 Ultimate Referense Suite DVD - энциклопедия, англоязычное издание: www.britannica.co.uk