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Trichromatic Color Vision
Trichromacy or trichromatism is the possession of three independent channels for conveying color information, derived from the three different types of cone cells in the eye. Organisms with trichromacy are called trichromats. The normal explanation of trichromacy is that the organism's retina contains three types of color receptors (called cone cells in vertebrates) with different absorption spectra. In actuality, the number of such receptor types may be greater than three, since different types may be active at different light intensities. In vertebrates with three types of cone cells, at low light intensities the rod cells may contribute to color vision. Humans and other animals that are trichromats Humans and some other mammals have evolved trichromacy based partly on pigments inherited from early vertebrates. In fish and birds, for example, four pigments are used for vision. These extra cone receptor visual pigments detect energy of other wavelengths, sometimes including ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tricolour Television Close Up
A triband is a vexillological style which consists of three stripes arranged to form a flag. These stripes may be two or three colours, and may be charged with an emblem in the middle stripe. Not all tribands are tricolour flags, which requires three unique colours. Design Outside of the name, which requires three bands of colour, there are no other requirements for what a triband must look like, so there are many flags that look very different from each other but are all considered tribands. Some triband flags (e.g. those of Germany, Russia and the Netherlands) have their stripes positioned horizontally, while others (e.g. that of Italy) position the stripes vertically. Often the stripes on a triband are of equal length and width, though this is not always the case, as can be seen in the flags of Colombia and Canada. Symbols on tribands may be seals, such as on the Belizean flag, or any manner of emblems of significance to the area the flag represents, such as in the flags o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New World Monkey
New World monkeys are the five families of primates that are found in the tropical regions of Mexico, Central and South America: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. The five families are ranked together as the Ceboidea (), the only extant superfamily in the parvorder Platyrrhini (). Platyrrhini is derived from the Greek for "broad nosed", and their noses are flatter than those of other simians, with sideways-facing nostrils. Monkeys in the family Atelidae, such as the spider monkey, are the only primates to have prehensile tails. New World monkeys' closest relatives are the other simians, the Catarrhini ("down-nosed"), comprising Old World monkeys and apes. New World monkeys descend from African simians that colonized South America, a line that split off about 40 million years ago. Evolutionary history About 40 million years ago, the Simiiformes infraorder split into the parvorders Platyrrhini (New World monkeys) and Catarrhini (apes and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferret
The ferret (''Mustela furo'') is a small, domesticated species belonging to the family Mustelidae. The ferret is most likely a domesticated form of the wild European polecat (''Mustela putorius''), as evidenced by the ferret's ability to interbreed with European polecats and produce hybrid offspring. Physically, ferrets resemble other mustelids because of their long, slender bodies. Including their tail, the average length of a ferret is about ; they weigh between ; and their fur can be black, brown, white, or a mixture of those colours. The species is sexually dimorphic, with males being considerably larger than females. Ferrets may have been domesticated since ancient times, but there is widespread disagreement because of the sparseness of written accounts and the inconsistency of those which survive. Contemporary scholarship agrees that ferrets were bred for sport, hunting rabbits in a practice known as rabbiting. In North America, the ferret has become an increasingly pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichromacy
Dichromacy (from Greek ''di'', meaning "two" and ''chromo'', meaning "color") is the state of having two types of functioning photoreceptors, called cone cells, in the eyes. Organisms with dichromacy are called dichromats. Dichromats require only two primary colors to be able to represent their visible gamut. By comparison, trichromats need three primary colors, and tetrachromats need four. Likewise, every color in a dichromat's gamut can be evoked monochromatic light. By comparison, every color in a trichromat's gamut can be evoked with a combination of monochromatic light and white light. Dichromacy in humans is a color vision deficiency in which one of the three cone cells is absent or not functioning and color is thereby reduced to two dimensions. Perception Dichromatic color vision is enabled by two types of cone cells with different spectral sensitivities and the neural framework to compare the excitation of the different cone cells. The resulting color vision ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichromat
Dichromacy (from Greek ''di'', meaning "two" and ''chromo'', meaning "color") is the state of having two types of functioning photoreceptors, called cone cells, in the eyes. Organisms with dichromacy are called dichromats. Dichromats require only two primary colors to be able to represent their visible gamut. By comparison, trichromats need three primary colors, and tetrachromats need four. Likewise, every color in a dichromat's gamut can be evoked monochromatic light. By comparison, every color in a trichromat's gamut can be evoked with a combination of monochromatic light and white light. Dichromacy in humans is a color vision deficiency in which one of the three cone cells is absent or not functioning and color is thereby reduced to two dimensions. Perception Dichromatic color vision is enabled by two types of cone cells with different spectral sensitivities and the neural framework to compare the excitation of the different cone cells. The resulting color vision is si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Behavioural
Behavior (American English) or behaviour (British English) is the range of actions of individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as well as the inanimate physical environment. It is the computed response of the system or organism to various stimuli or inputs, whether internal or external, conscious or subconscious, overt or covert, and voluntary or involuntary. While some behavior is produced in response to an organism's environment (extrinsic motivation), behavior can also be the product of intrinsic motivation, also referred to as "agency" or "free will". Taking a behavior informatics perspective, a behavior consists of actor, operation, interactions, and their properties. This can be represented as a behavior vector. Models Biology Definition Behavior may be defined as "the internally coordinated responses (actions or inactions) of whole living organisms (individuals or groups) to in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, origin, evolution, and distribution of life. Central to biology are five fundamental themes: the cell as the basic unit of life, genes and heredity as the basis of inheritance, evolution as the driver of biological diversity, energy transformation for sustaining life processes, and the maintenance of internal stability (homeostasis). Biology examines life across multiple levels of organization, from molecules and cells to organisms, populations, and ecosystems. Subdisciplines include molecular biology, physiology, ecology, evolutionary biology, developmental biology, and systematics, among others. Each of these fields applies a range of methods to investigate biological phenomena, including observation, experimentation, and mathematical modeling. Modern biology is grounded i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution
Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. The process of evolution has given rise to biodiversity at every level of biological organisation. The scientific theory of evolution by natural selection was conceived independently by two British naturalists, Charles Darwin and Alfred Russel Wallace, in the mid-19th century as an explanation for why organisms are adapted to their physical and biological environments. The theory was first set out in detail in Darwin's book ''On the Origin of Species''. Evolution by natural selection is established by observable facts about living organisms: (1) more offspring are often produced than can possibly survive; (2) phenotypic variatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reptile
Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocephalia. About 12,000 living species of reptiles are listed in the Reptile Database. The study of the traditional reptile orders, customarily in combination with the study of modern amphibians, is called herpetology. Reptiles have been subject to several conflicting Taxonomy, taxonomic definitions. In Linnaean taxonomy, reptiles are gathered together under the Class (biology), class Reptilia ( ), which corresponds to common usage. Modern Cladistics, cladistic taxonomy regards that group as Paraphyly, paraphyletic, since Genetics, genetic and Paleontology, paleontological evidence has determined that birds (class Aves), as members of Dinosauria, are more closely related to living crocodilians than to other reptiles, and are thus nested among re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heredity
Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents. Through heredity, variations between individuals can accumulate and cause species to evolve by natural selection. The study of heredity in biology is genetics. Overview In humans, eye color is an example of an inherited characteristic: an individual might inherit the "brown-eye trait" from one of the parents. Inherited traits are controlled by genes and the complete set of genes within an organism's genome is called its genotype. The complete set of observable traits of the structure and behavior of an organism is called its phenotype. These traits arise from the interaction of the organism's genotype with the environment. As a result, many aspects of an organism's phenotype are not inherited. For example, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fat-tailed Dunnart
The fat-tailed dunnart (''Sminthopsis crassicaudata'') is a species of mouse-like marsupial of the Dasyuridae, the family that includes the little red kaluta, quolls, and the Tasmanian devil. Description It has an average body length of with a tail of . Its ear length is . One of the smallest carnivorous marsupials, it varies in weight between . The tail becomes fat a few millimeters from the proximal end and remains so right up to the tip. The dunnart has trichromat vision, similar to that of some other marsupials as well as primates, but unlike most mammals, which have dichromat vision. Distribution and habitat The range of ''S. crassicaudata'' in Australia is in diverse habitats except for the Kimberley region of Western Australia and the northern Northern Territory like Arnhem Land and Kakadu National Park, but avoids the Wannon and Mallee scrub habitats in Victoria. In the northeast of Victoria, the species can also be found in grassy woodlands and samphire s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Honey Possum
The honey possum or noolbenger (''Tarsipes rostratus''), is a tiny species of marsupial that feeds on the nectar and pollen of a diverse range of flowering plants. Found only in southwest Australia, it is an important pollinator for such plants as '' Banksia attenuata'', '' Banksia coccinea'' and ''Adenanthos cuneatus''. Taxonomy The first description of the diprotodont species was published by Paul Gervais and Jules Verreaux on 3 March 1842, referring to a specimen collected by Verreaux. The lectotype nominated for this species, held in the collection at National Museum of Natural History, France, was collected the Swan River Colony. A description of a second species ''Tarsipes spenserae'', published five days later by John Edward Gray and current until the 1970s, was thought to have been published earlier by T. S. Palmer in 1904 and displaced the usage of ''T. rostratus''. A review by Mahoney in 1984 again reduced ''T. spenserae'' to a synonym for the species, as was t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
