23-10-2011, 12:40 AM
بحث e ثانويه عامه
لكم تحياتي و اتريا الردود الطيبه
و السموحه على القصور
United Arad Emirates
My report about :
Iam very happy to write about this animal because it is the famous animal . It is very famous because it is very huge and nice in same time . I would like to give you a lot information , and I hope you like my report .
The Elephants :
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct. Three species of elephant are generally recognized today: the African bush elephant, the African forest elephant and the Asian elephant (also known as the Indian elephant). However, some researchers postulate the existence of a fourth species of elephant in West Africa. All other species and genera of Elephantidae are extinct. Most have been extinct since the last ice age, although dwarf forms of mammoths might have survived as late as 2,000 BCE. Elephants and other Elephantidae were once classified with other thick-skinned animals in a now invalid order, Pachydermata.
Elephants are the largest living land animals on Earth today. The elephant's gestation period is 22 months, the longest of any land animal. At birth, an elephant calf typically weighs 105 kilograms (230 lb). They typically live for 50 to 70 years, but the oldest recorded elephant lived for 82 years. The largest elephant ever recorded was shot in Angola in 1956. This male weighed about 24,000 lb (11,000 kg), with a shoulder height of 3.96 metres (13.0 ft), a metre (yard) taller than the average male African elephant. The smallest elephants, about the size of a calf or a large pig, were a prehistoric species that lived on the island of Crete during the Pleistocene epoch.
Elephants are a symbol of wisdom in Asian cultures and are famed for their memory and intelligence, where their intelligence level is thought to be equal to that of dolphins and primates. Aristotle once said the elephant was "the beast which passeth all others in wit and mind."] The word "elephant" has its origins in the Greek ἐλέφας, meaning "ivory" or "elephant".
According to observations, healthy adult elephants have no natural predators, although lions may take calves or weak individuals. They are, however, threatened by human intrusion and poaching.
Olifant and its variations (ex. oliphant, olyphant) are archaic spellings of elephant. Aside from elephants, the word has been used to refer to ivory, elephant tusks, musical horns made of elephant tusks, or a musical instrument resembling such horns.
It appears in Middle English as olifant or olifaunt, and was borrowed from Medieval French olifanz. The French word owes something to both Old High German olbenta "camel", and to Latin elephantus "elephant", a word of Greek origin. OHG olbenta is a word of old Germanic origin; cf. Gothic ulbandus also meaning "camel". But the form of the OHG and Gothic words suggests it is also a borrowing, perhaps indeed directly or indirectly from .
Taxonomy and evolution :
The African elephant genus contains two or, arguably, three living species; whereas the Asian elephant species is the only surviving member of the Asian elephant genus, but can be divided into four subspecies. The African and the Asian elephant diverged from a common ancestor some 7.6 million years ago.
The Elephants of the genus Loxodonta, known collectively as African elephants, are currently found in 37 countries in Africa.
African elephants are distinguished from Asian elephants in several ways, the most noticeable being their much larger ears. Also, the African elephant is typically larger than the Asian elephant and has a concave back. In Asian elephants, only males have tusks, but both males and females of African elephants have tusks and are usually less hairy than their Asian cousins.
African elephants have traditionally been classified as a single species comprising two distinct subspecies, namely the savanna elephant (Loxodonta africana africana) and the forest elephant (Loxodonta africana cyclotis), but recent DNA analysis suggests that these may actually constitute distinct species. This split is not universally accepted by experts. A third species of African elephant has also been proposed.
The authors of an analysis of nuclear DNA extracted from "African savanna elephant, African forest elephant, Asian elephant, the extinct American mastodon, and the woolly mammoth" concluded in 2010 that African savanna and forest elephants are indeed separate species:
We unequivocally establish that the Asian elephant is the sister species to the woolly mammoth. A surprising finding from our study is that the divergence of African savanna and forest elephants—which some have argued to be two populations of the same species—is about as ancient as the divergence of Asian elephants and mammoths. Given their ancient divergence, we conclude that African savanna and forest elephants should be classified as two distinct species.
This reclassification has implications for conservation. If there are two separate species, each will be less abundant (particularly the rarer) and could be more endangered than a more numerous and wide-ranging single species. There is also a potential danger that if the forest elephant is not explicitly listed as an endangered species, poachers and smugglers might be able to evade the law forbidding trade in endangered animals and their products.
The forest elephant and the savanna elephant can hybridize (interbreed), though their preferences for different terrains reduce such opportunities. As the African elephant has only recently been recognized to comprise two separate species, groups of captive elephants have not been comprehensively classified and some could well be hybrids.
Under the new two species classification, Loxodonta africana refers specifically to the savanna elephant, the largest of all elephants. It is the largest land animal, with males standing 3.2 metres (10 ft) to 4 metres (13 ft) at the shoulder and weighing 3,500 kilograms (7,700 lb) up to a reported 12,000 kilograms (26,000 lb). The female is smaller, standing about 3 metres (9.8 ft) at the shoulder. Most often, savanna elephants are found in open grasslands, marshes, and lakeshores. They range over much of the savanna zone south of the Sahara.
The other putative species, the forest elephant (Loxodonta cyclotis), is usually smaller and rounder, and its tusks thinner and straighter compared with the savanna elephant. The forest elephant can weigh up to 4,500 kilograms (9,900 lb) and stand about 3 metres (10 ft) tall. Much less is known about these animals than their savanna cousins, because environmental and political obstacles make them difficult to study. Normally, they inhabit the dense African rain forests of central and western Africa, although occasionally they roam the edges of forests, thus overlapping the savanna elephant home ranges and hybridizing. In 1979, Iain Douglas-Hamilton estimated the continental population of African elephants at around 1.3 million animals. This estimate is controversial and is believed to be a gross overestimate, but it is very widely cited and has become a de facto baseline that continues to be incorrectly used to quantify downward population trends in the species. Through the 1980s, Loxodonta received worldwide attention due to the dwindling numbers of major populations in East Africa, largely as a result of poaching. According to IUCN’s African Elephant Status Report 2007, there are between 470,000 and 690,000 African elephants in the wild. Although this estimate only covers about half of the total elephant range, experts do not believe the true figure to be much higher, as it is unlikely that large populations remain to be discovered. By far, the largest populations are now found in southern and eastern Africa, which together account for the majority of the continental population. According to a recent analysis by IUCN experts, most major populations in eastern and southern Africa are stable or have been steadily increasing since the mid-1990s, at an average rate of 4.5% per year.
Elephant populations in West Africa, on the other hand, are generally small and fragmented, and only account for a small proportion of the continental total. Much uncertainty remains as to the size of the elephant population in central Africa, where the prevalence of forest makes population surveys difficult, but poaching for ivory and bushmeat is believed to be intense through much of the region. South African elephant population more than doubled, rising from 8,000 to over 20,000, in the thirteen years after a 1995 ban on the trade in elephant ivory. The ban on the ivory trade in southern Africa (but not elsewhere) was lifted in February 2008, sparking controversy among environmental groups.
Greek "ἐλέφας" (elephas), which in Homer only meant "ivory" but from Herodotus and on the word also referred to the animal. The earliest attested form of the word is the Mycenaean Greek e-re-pa-to, written in Linear B syllabic script .
The end . This is all my report , and I tell you about the elephant . I hope you know a lot about this animal . Thank you for your time .
Reference : http://auto.search.msn.com/response....h=5&prov=&utf8