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African Elephants
African elephants are members of the genus ''Loxodonta'' comprising two living elephant species, the African bush elephant (''L. africana'') and the smaller African forest elephant (''L. cyclotis''). Both are social herbivores with grey skin. However, they differ in the size and colour of their tusks as well as the shape and size of their ears and skulls. Both species are at a pertinent risk of extinction according to the IUCN Red List; as of 2021, the bush elephant is considered endangered while the forest elephant is considered critically endangered. They are threatened by habitat loss and fragmentation, along with poaching for the illegal ivory trade in several range countries. ''Loxodonta'' is one of two extant genera in the family Elephantidae. The name refers to the lozenge-shaped enamel of their molar teeth. Fossil remains of ''Loxodonta'' species have been found in Africa, spanning from the Late Miocene (from around 7–6 million years ago) onwards. Etymology The na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene followed the Oligocene and preceded the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by distinct global events but by regionally defined transitions from the warmer Oligocene to the cooler Pliocene Epoch. During the Early Miocene, Afro-Arabia collided with Eurasia, severing the connection between the Mediterranean and Indian Oceans, and allowing the interchange of fauna between Eurasia and Africa, including the dispersal of proboscideans and Ape, hominoids into Eurasia. During the late Miocene, the conn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tusk
Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine tooth, canine teeth, as with Narwhal, narwhals, chevrotains, musk deer, water deer, muntjac, pigs, peccary, peccaries, hippopotamuses and walruses, or, in the case of elephants, elongated incisors. Tusks share common features such as extra-oral position, growth pattern, composition and structure, and lack of contribution to ingestion. Tusks are thought to have adapted to the extra-oral environments, like dry or aquatic or arctic. In most tusked species both the males and the females have tusks although the males' are larger. Most mammals with tusks have a pair of them growing out from either side of the mouth. Tusks are generally curved and have a smooth, continuous surface. The male narwhal's straight single Helix, helical tusk, which usually grows out from the left of the mouth, is an exception to the typical features of tusks describ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enamel Of Teeth
Tooth enamel is one of the four major tissues that make up the tooth in humans and many animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, cementum, and dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. Features Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%),Ross ''et al.'', p. 485 with water and organic material composing the rest.Ten Cate's Oral Histology, Nancy, Elsevier, pp. 70–94 The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed on the tooth while the tooth develops within the jaw bone before it erupts into the mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lozenge (shape)
A lozenge ( ; symbol: ), often referred to as a diamond, is a form of rhombus. The definition of ''lozenge'' is not strictly fixed, and the word is sometimes used simply as a synonym () for ''rhombus''. Most often, though, lozenge refers to a thin rhombus—a rhombus with two acute and two obtuse angles, especially one with acute angles of 45°. The lozenge shape is often used in parquetry (with acute angles that are 360°/''n'' with ''n'' being an integer higher than 4, because they can be used to form a set of tiles of the same shape and size, reusable to cover the plane in various geometric patterns as the result of a tiling process called tessellation in mathematics) and as decorative art, decoration on ceramics (art), ceramics, Silver (household), silverware and textiles. It also features in heraldry and Suit (cards), playing cards. Symbolism The lozenge motif dates from the Neolithic and Paleolithic art, Paleolithic period in Eastern Europe and represents a sown Field (agr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek Dark Ages, Dark Ages (), the Archaic Greece, Archaic or Homeric Greek, Homeric period (), and the Classical Greece, Classical period (). Ancient Greek was the language of Homer and of fifth-century Athens, fifth-century Athenian historians, playwrights, and Ancient Greek philosophy, philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Homeric Greek, Epic and Classical periods of the language, which are the best-attested periods and considered most typical of Ancient Greek. From the Hellenistic period (), Ancient Greek was followed by Koine Greek, which is regar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Africa
Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surface area.Sayre, April Pulley (1999), ''Africa'', Twenty-First Century Books. . With nearly billion people as of , it accounts for about of the world's human population. Demographics of Africa, Africa's population is the youngest among all the continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4. Based on 2024 projections, Africa's population will exceed 3.8 billion people by 2100. Africa is the least wealthy inhabited continent per capita and second-least wealthy by total wealth, ahead of Oceania. Scholars have attributed this to different factors including Geography of Africa, geography, Climate of Africa, climate, corruption, Scramble for Africa, colonialism, the Cold War, and neocolonialism. Despite this lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good understanding of the pattern of diversification of life on Earth. In addition, the record can predict and fill gaps such as the discovery of '' Tiktaalik'' in the arctic of Canada. Paleontology includes the study of fossils: their age, method of formation, and evolutionary significance. Specimens are sometimes considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years to 4.1 billion years old. Early edition, published online before prin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elephantidae
Elephantidae is a family (biology), family of large, herbivorous proboscidean mammals which includes the living Elephant, elephants (belonging to the genera ''Elephas'' and ''Loxodonta''), as well as a number of extinct genera like ''Mammuthus'' (mammoths) and ''Palaeoloxodon''. They are large terrestrial animal, terrestrial mammals with a snout modified into a Elephant#Trunk, trunk and teeth modified into tusks. Most Genus, genera and species in the family are extinction, extinct. The family was first described by John Edward Gray in 1821, and later assigned to taxonomic ranks within the order Proboscidea. Elephantidae has been revised by various authors to include or exclude other extinct proboscidean genera. Description Elephantids are distinguished from more basal proboscideans like gomphotheres by their teeth, which have parallel lophs, formed from the merger of the cusps found in the teeth of more basal proboscideans, which are bound by cementum. In later elephantids, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ivory Trade
The ivory trade is the commercial, often illegal trade in the ivory tusks of the hippopotamus, walrus, narwhal, black and white rhinos, mammoth, and most commonly, African elephant, African and Asian elephants. Ivory has been traded for hundreds of years by people in Africa and Asia, resulting in restrictions and bans. Ivory was formerly used to make piano keys and other decorative items because of the white color it presents when processed but the piano industry abandoned ivory as a key covering material in the 1980s in favor of other materials such as plastic. Also, synthetic ivory has been developed which can be used as an alternative material for making piano keys. Elephant ivory Elephant ivory has been exported from Africa and Asia for millennia with records going back to the 14th century Common Era, BCE. Transport of the heavy commodity was always difficult, and with the establishment of the early-modern slave trades from East and West Africa, freshly captured Slavery, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poaching
Poaching is the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set against the hunting privileges of nobility and territorial rulers. Since the 1980s, the term "poaching" has also been used to refer to the illegal harvesting of wild plants. In agricultural terms, the term 'poaching' is also applied to the loss of soils or grass by the damaging action of feet of livestock, which can affect availability of productive land, water pollution through increased runoff and welfare issues for cattle. Stealing livestock, as in cattle raiding, classifies as theft rather than poaching. The United Nations' Sustainable Development Goal 15 enshrines the sustainable use of all wildlife. It targets the taking of action on dealing with poaching and trafficking of protected species of flora and fauna to ensure their availability for present ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat Loss
Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease in biodiversity and Abundance (ecology), species numbers. Habitat destruction is in fact the leading cause of biodiversity loss and species extinction worldwide. Humans contribute to habitat destruction through the Exploitation of natural resources, use of natural resources, agriculture, industrial production and urbanization (urban sprawl). Other activities include mining, logging and trawling. Environmental factors can contribute to habitat destruction more indirectly. Geological processes, climate change, introduced species, introduction of invasive species, ecosystem nutrient depletion, water pollution, water and noise pollution are some examples. Loss of habitat can be preceded by an initial habitat fragmentation. Fragmentation and lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Critically Endangered
An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of the 157,190 species currently on the IUCN Red List, 9,760 of those are listed as critically endangered, with 1,302 being possibly extinct and 67 possibly extinct in the wild. The IUCN Red List provides the public with information regarding the conservation status of animal, fungi, and plant species. It divides various species into seven different categories of conservation that are based on habitat range, population size, habitat, threats, etc. Each category represents a different level of global extinction risk. Species that are considered to be critically endangered are placed within the "Threatened" category. As the IUCN Red List does not consider a species extinct until extensive targeted surveys have been conducted, species that a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
