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Weapon (biology)
In biology, weapons are traits that are used by males to fight one another off for access to mates. A mate is won in battle either by a male chasing off a fellow competitor or killing it off, usually leaving the victor as the only option for the female to reproduce with. However, because stronger organisms, whether mentally or physically, are usually favored in combat, this also leads to the evolution of stronger organisms in species that use combat as a way to secure mates, via intrasexual selection."Charles Darwin & Evolution." Charles Darwin & Evolution. Apr. 2014. . Examples of weapons include: antlers, horns, and ossicone Ossicones are columnar or conical skin-covered bone structures on the heads of giraffes, male okapi, and some of their extinct relatives. Ossicones are distinguished from the superficially similar structures of horns and antlers by their uniqu ...s. Gallery References Mating Weapons Sexual selection {{Animal anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biology
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary information encoded in genes, which can be transmitted to future generations. Another major theme is evolution, which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move, grow, and reproduce. Finally, all organisms are able to regulate their own internal environments. Biologists are able to study life at multiple levels of organization, from the molecular biology of a cell to the anatomy and physiology of plants and animals, and evolution of populations.Based on definition from: Hence, there are multiple subdisciplines within biology, each defined by the nature of their research questions and the tools that they use. Like other scientists, biologists use the sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Deer
The red deer (''Cervus elaphus'') is one of the largest deer species. A male red deer is called a stag or hart, and a female is called a hind. The red deer inhabits most of Europe, the Caucasus Mountains region, Anatolia, Iran, and parts of western Asia. It also inhabits the Atlas Mountains of Northern Africa; its early ancestors are thought to have crossed over to Morocco, then to Algeria, Libya and Tunisia via the Strait of Gibraltar, becoming the only species of true deer (Cervidae) to inhabit Africa. Red deer have been introduced to other areas, including Australia, New Zealand, the United States, Canada, Peru, Uruguay, Chile and Argentina. In many parts of the world, the meat ( venison) from red deer is used as a food source. Red deer are ruminants, characterized by a four-chambered stomach. Genetic evidence indicates that the red deer, as traditionally defined, is a species group, rather than a single species, though exactly how many species the group includes remains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triceratops
''Triceratops'' ( ; ) is a genus of herbivorous chasmosaurine ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the Late Cretaceous period, about 68 million years ago in what is now North America. It is one of the last-known non-avian dinosaur genera, and became extinct in the Cretaceous–Paleogene extinction event 66 million years ago. The name ''Triceratops'', which literally means 'three-horned face', is derived from the Greek words () meaning 'three', () meaning 'horn', and () meaning 'face'. Bearing a large bony frill, three horns on the skull, and a large four-legged body, exhibiting convergent evolution with rhinoceroses and bovines, ''Triceratops'' is one of the most recognizable of all dinosaurs and the most well-known ceratopsid. It was also one of the largest, up to long and in body mass. It shared the landscape with and was most likely preyed upon by ''Tyrannosaurus'', though it is less certain that two adults did ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhinoceros Beetles
Dynastinae or rhinoceros beetles are a subfamily of the scarab beetle family (Scarabaeidae). Other common names – some for particular groups of rhinoceros beetles – include Hercules beetles, unicorn beetles or horn beetles. Over 1500 species and 225 genera of rhinoceros beetles are known. Many rhinoceros beetles are well known for their unique shapes and large sizes. Some famous species are, for example, the Atlas beetle (''Chalcosoma atlas''), common rhinoceros beetle (''Xylotrupes ulysses''), elephant beetle (''Megasoma elephas''), European rhinoceros beetle (''Oryctes nasicornis''), Hercules beetle (''Dynastes hercules''), Japanese rhinoceros beetle or ''kabutomushi'' (''Allomyrina dichotoma''), ox beetle (''Strategus aloeus'') and the Eastern Hercules beetle (''Dynastes tityus''). Description and ecology The Dynastinae are among the largest of beetles, reaching more than in length, but are completely harmless to humans because they cannot bite or st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhino
A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species of the superfamily Rhinocerotoidea.) Two of the extant species are native to Africa, and three to South and Southeast Asia. Rhinoceroses are some of the largest remaining megafauna: all weigh at least one tonne in adulthood. They have a herbivorous diet, small brains (400–600 g) for mammals of their size, one or two horns, and a thick (1.5–5 cm), protective skin formed from layers of collagen positioned in a lattice structure. They generally eat leafy material, although their ability to ferment food in their hindgut allows them to subsist on more fibrous plant matter when necessary. Unlike other perissodactyls, the two African species of rhinoceros lack teeth at the front of their mouths; they rely instead on their lips to pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chameleon
Chameleons or chamaeleons (family Chamaeleonidae) are a distinctive and highly specialized clade of Old World lizards with 202 species described as of June 2015. The members of this family are best known for their distinct range of colors, being capable of shifting to different hues and degrees of brightness. The large number of species in the family exhibit considerable variability in their capacity to change color. For some, it is more of a shift of brightness (shades of brown); for others, a plethora of color-combinations (reds, yellows, greens, blues) can be seen. Chameleons are distinguished by their zygodactylous feet, their prehensile tail, their laterally compressed bodies, their head casques, their projectile tongues, their swaying gait, and crests or horns on their brow and snout. Chameleons' eyes are independently mobile, and because of this there are two separate, individual images that the brain is analyzing of the chameleon’s environment. When hunting prey, they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giraffe
The giraffe is a large African hoofed mammal belonging to the genus ''Giraffa''. It is the tallest living terrestrial animal and the largest ruminant on Earth. Traditionally, giraffes were thought to be one species, '' Giraffa camelopardalis'', with nine subspecies. Most recently, researchers proposed dividing them into up to eight extant species due to new research into their mitochondrial and nuclear DNA, as well as morphological measurements. Seven other extinct species of ''Giraffa'' are known from the fossil record. The giraffe's chief distinguishing characteristics are its extremely long neck and legs, its horn-like ossicones, and its spotted coat patterns. It is classified under the family Giraffidae, along with its closest extant relative, the okapi. Its scattered range extends from Chad in the north to South Africa in the south, and from Niger in the west to Somalia in the east. Giraffes usually inhabit savannahs and woodlands. Their food source is leaves, fru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ossicones
Ossicones are columnar or conical skin-covered bone structures on the heads of giraffes, male okapi, and some of their extinct relatives. Ossicones are distinguished from the superficially similar structures of horns and antlers by their unique development and a permanent covering of skin and fur. Structure Giraffe ossicones consist of a highly vascularized and innervated bone core covered with vascularized and innervated skin. The base of an ossicone is attached to the skull with vascularized innervated connective tissue. Ossicones are formed at late gestation, but in early development they are not bony and not fused to the skull yet. Ossicones usually fuse to the skull at sexual maturity. All male and female giraffes have a pair of parietal ossicones on the parietal bones of the skull. Males also usually have a single median ossicone on the frontal bone that is larger in northern animals and smaller in southern giraffes. Giraffes can also have small additional paired occipi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impala
The impala or rooibok (''Aepyceros melampus'') is a medium-sized antelope found in eastern and southern Africa. The only extant member of the genus ''Aepyceros'' and tribe Aepycerotini, it was first described to European audiences by German zoologist Hinrich Lichtenstein in 1812. Two subspecies are recognised—the common impala, and the larger and darker black-faced impala. The impala reaches at the shoulder and weighs . It features a glossy, reddish brown coat. The male's slender, lyre-shaped horns are long. Active mainly during the day, the impala may be gregarious or territorial depending upon the climate and geography. Three distinct social groups can be observed: the territorial males, bachelor herds and female herds. The impala is known for two characteristic leaps that constitute an anti-predator strategy. Browsers as well as grazers, impala feed on monocots, dicots, forbs, fruits and acacia pods (whenever available). An annual, three-week-long rut takes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antlers
Antlers are extensions of an animal's skull found in members of the Cervidae (deer) family. Antlers are a single structure composed of bone, cartilage, fibrous tissue, skin, nerves, and blood vessels. They are generally found only on males, with the exception of reindeer/caribou. Antlers are shed and regrown each year and function primarily as objects of sexual attraction and as weapons. In contrast to antlers, horns—found on pronghorns and bovids, such as sheep, goats, bison and cattle—are two-part structures that usually do not shed. A horn's interior of bone is covered by an exterior sheath made of keratin (the same material as human fingernails and toenails). Etymology Antler comes from the Old French ''antoillier '' (see present French : "Andouiller", from'' ant-, ''meaning before,'' oeil, ''meaning eye and'' -ier'', a suffix indicating an action or state of being) possibly from some form of an unattested Latin word ''*anteocularis'', "before the eye" (and appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Males
Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and asexually. Most male mammals, including male humans, have a Y chromosome, which codes for the production of larger amounts of testosterone to develop male reproductive organs. Not all species share a common sex-determination system. In most animals, including humans, sex is determined genetically; however, species such as ''Cymothoa exigua'' change sex depending on the number of females present in the vicinity. In humans, the word ''male'' can also be used to refer to gender in the social sense of gender role or gender identity. Overview The existence of separate sexes has evolved independently at different times and in different lineages, an example ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ossicone
Ossicones are columnar or conical skin-covered bone structures on the heads of giraffes, male okapi, and some of their extinct relatives. Ossicones are distinguished from the superficially similar structures of horns and antlers by their unique development and a permanent covering of skin and fur. Structure Giraffe ossicones consist of a highly vascularized and innervated bone core covered with vascularized and innervated skin. The base of an ossicone is attached to the skull with vascularized innervated connective tissue. Ossicones are formed at late gestation, but in early development they are not bony and not fused to the skull yet. Ossicones usually fuse to the skull at sexual maturity. All male and female giraffes have a pair of parietal ossicones on the parietal bones of the skull. Males also usually have a single median ossicone on the frontal bone that is larger in northern animals and smaller in southern giraffes. Giraffes can also have small additional paired occipi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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