2010年5月30日星期日

Coelacanth






Another animal which already extinct is coelacanth fish..
this fish looks quite ugly..
Coelacanth (pronounced /ˈsiːləkænθ/, adaptation of Modern Latin Cœlacanthus "hollow spine", from Greek κοῖλ-ος koilos "hollow" + ἄκανθ-α akantha "spine", referring to the hollow spines of the fins) is the common name for an order of fish that includes the oldest living lineage of Sarcopterygii (lobe-finned fish + tetrapods) known to date.

The coelacanths, which are related to lungfishes and tetrapods, were believed to have been extinct since the end of the Cretaceous period. The coelacanth is actually more related to tetrapods than the ray-finned fish. They were considered[by whom?] the "missing link" between the fish and the tetrapods until the first Latimeria specimen was found off the east coast of South Africa, off the Chalumna River in 1938.They are, therefore, a Lazarus taxon. Since 1938, Latimeria chalumnae have been found in the Comoros, Kenya, Tanzania, Mozambique, Madagascar, and in iSimangaliso Wetland Park, Kwazulu-Natal in South Africa. The second extant species, L. menadoensis, was described fromManado Sulawesi, Indonesia in 1999 by Pouyaud the great french evolutionist.et al. based on a specimen discovered by Erdmann in 1998 and deposited in Indonesian Institute of Sciences (LIPI). The first specimen of this species was only photographed at a local market by Arnaz and Mark Erdmann before being bought by a shopper.

The coelacanth has no real commercial value, apart from being coveted by museums and private collectors. As a food fish the coelacanth is almost worthless as its tissues exude oils that give the flesh a foul flavor.[3] The continued survivability of the coelacanth may be at threat due to commercial deep-sea trawling.

They first appeared in the fossil record in the Middle Devonian.[5] Prehistoric species of coelacanth lived in many bodies of water in Late Paleozoic and Mesozoic times.

Coelacanths are lobe-finned fish with the pectoral and anal fins on fleshy stalks supported by bones, and the tail or caudal fin diphycercal (divided into three lobes), the middle one of which also includes a continuation of the notochord. Coelacanths have modified cosmoid scales, which are thinner than true cosmoid scales. Coelacanths also have a special electroreceptive device called a rostral organ in the front of the skull, which probably helps in prey detection. The small device also could help the balance of the fish, as electrolocation could be a factor in the way this fish moves.

Irish Deer






Today i will like to continue my topic about the animal which extinct..
these animals which extinct are the creatures of the past..
we cant see these animals anymore..
so same as what i did before..
i will do some research on it and post it on my blog..
hope everyone will like it..
hope everyone will remember there animals live in this earth before..
today the extinct animal is Irish Deer...
The Irish Deer or Giant Deer (Megaloceros giganteus), was a species of Megaloceros and one of the largest deer that ever lived. Its range extended across Eurasia, from Ireland to east of Lake Baikal, during the Late Pleistocene. The latest known remains of the species have been carbon dated to about 7,700 years ago.Although most skeletons have been found in Irish bogs, the animal was not exclusively Irish and was not closely related to either of the living species currently called elk; for this reason, the name "Giant Deer" is often used in more recent publications.
It first appeared about 400,000 years ago. It possibly evolved from M. antecedens. The earlier taxon — sometimes considered a paleosubspecies M. giganteus antecedens — is similar but had more compact antlers.But,it died out about 7700years ago.
The Irish Deer stood about 2.1 metres (6.9 ft) tall at the shoulders, and it had the largest antlers of any known cervid (a maximum of 3.65 m (12.0 ft) from tip to tip and weighing up to 40 kilograms (88 lb)). In body size, the Irish Elk matched the extant moose subspecies of Alaska (Alces alces gigas) as the largest known deer.A significant collection of M. giganteus skeletons can be found at the Natural History Museum in Dublin.
It is easy to advance a number of hypotheses regarding the disappearance of the more localized populations of this species. The situation is less clear regarding the final demise of the Irish Elk in continental Eurasia east of the Urals. Stuart et al. (2004) tentatively suggest that a combination of human presence along rivers and slow decrease in habitat quality in upland areas presented the last Irish Elk with the choice of either good habitat but considerable hunting pressure, or general absence of humans in a suboptimal habitat.

2010年5月19日星期三

Happy birthday,Pn Lim!

Happy birthday,Pn Lim!
Today my classmates bought a ice-cream cake..
We want to celebrate Pn Lim birthday together..
She looks shocked and happy with our celebration..
It is nice and everyone seems to be enjoyed..
And,the cake is delicious also..
She makes a wish that we can score A in her subject,PA..
Anyway,thanks Pn Lim try her best to teach us..
She did a lot of things for us,like giving us exercise,trying to discuss our mistakes,talking about some issue for us to listen...
Her knowledge helps us a lot..
I am appreciate that she is our PA teacher..
i will try to score well in STPM de..
dont worry,teacher..

Sea Cow






today i saw an interesting topic in the newspaper..
it is about the extinction of animal..
one of the animal is sea cow..
this is my first time i know this animal..
and,i look at the picture..
the animal quite look like a cow...
so today i have done some research on this animal..
i would like to share this with you all..
Steller's sea cow (Hydrodamalis gigas) is a large extinct sirenian mammal. Formerly abundant throughout the North Pacific, its range was limited to a single, isolated population on the uninhabited Commander Islands by 1741 when it was first described by Georg Wilhelm Steller, chief naturalist on an expedition led by explorer Vitus Bering. Within 27 years of discovery by Europeans, the slow moving and easily captured Steller's sea cow was hunted to extinction.
The sea cow grew at least 8 metres (26 ft)to 9 meters or 30 feet long,much larger than the manatee or dugong. Steller's work contains two contradictory weights: 4 and 24.3 tons. The true value probably lies between these figures, around 8-10 tons.It looked somewhat like a large seal, but had two stout forelimbs and a whale-like tail. According to Steller, "The animal never comes out on shore, but always lives in the water. Its skin is black and thick, like the bark of an old oak…, its head in proportion to the body is small…, it has no teeth, but only two flat white bones—one above, the other below". It was completely tame, according to Steller. They fed on a variety of kelp. Wherever sea cows had been feeding, heaps of stalks and roots of kelp were washed ashore. The sea cow was also a slow swimmer and apparently was unable to submerge.
The population of sea cows was small and limited in range when Steller first described them. Steller said they were numerous and found in herds, but zoologist Leonhard Hess Stejneger later estimated that at discovery there had been fewer than 1,500 remaining, and thus had been in immediate danger of extinction from overhunting by humans.They were quickly wiped out by the sailors, seal hunters, and fur traders that followed Bering's route past the islands to Alaska, who hunted them both for food and for their skins, which were used to make boats. They were also hunted for their valuable subcutaneous fat, which was not only used for food (usually as a butter substitute), but also for oil lamps because it did not give off any smoke or odor and could be kept for a long time in warm weather without spoiling. By 1768, 27 years after it had been discovered by Europeans, Steller's sea cow was extinct.