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Directional Selection
In population genetics, directional selection is a type of natural selection in which one extreme phenotype is favored over both the other extreme and moderate phenotypes. This genetic selection causes the allele frequency to shift toward the chosen extreme over time as allele ratios change from generation to generation. The advantageous extreme allele will increase in frequency among the population as a consequence of survival and reproduction differences among the different present phenotypes in the population. The allele fluctuations as a result of directional selection can be independent of the dominance of the allele, and in some cases if the allele is recessive, it can eventually become fixed in the population. Directional selection was first identified and described by naturalist Charles Darwin in his book ''On the Origin of Species'' published in 1859. He identified it as a type of natural selection along with stabilizing selection and disruptive selection. These types ...
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Genetic Distribution
Genetic diversity is the total number of Genetics, genetic characteristics in the genetic makeup of a species. It ranges widely, from the number of species to differences within species, and can be correlated to the span of survival for a species. It is distinguished from ''genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral su ...
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Ecuador
Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contains the Galapagos Islands in the Pacific, about west of the mainland. The country's Capital city, capital is Quito and its largest city is Guayaquil. The land that comprises modern-day Ecuador was once home to several groups of Indigenous peoples in Ecuador, indigenous peoples that were gradually incorporated into the Inca Empire during the 15th century. The territory was Spanish colonization of the Americas, colonized by the Spanish Empire during the 16th century, achieving independence in 1820 as part of Gran Colombia, from which it emerged as a sovereign state in 1830. The legacy of both empires is reflected in Ecuador's ethnically diverse population, with most of its million people being mestizos, followed by large minorities of Europe ...
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Anadromous
Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear. Fish migrations involve movements of schools of fish on a scale and duration larger than those arising during normal daily activities. Some particular types of migration are ''anadromous'', in which adult fish live in the sea and migrate into fresh water to spawn; and ''catadromous'', in which adult fish live in fresh water and migrate into salt water to spawn. Marine forage fish often make large migrations between their spawning, feeding and nursery grounds. Their movements are associated with ocean currents and with the availability of food in different areas at different times of the year. The migratory ...
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Salmon
Salmon (; : salmon) are any of several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the genera ''Salmo'' and ''Oncorhynchus'' of the family (biology), family Salmonidae, native to tributary, tributaries of the North Atlantic (''Salmo'') and North Pacific (''Oncorhynchus'') basins. ''Salmon'' is a colloquial or common name used for fish in this group, but is not a scientific name. Other closely related fish in the same family include trout, Salvelinus, char, Thymallus, grayling, Freshwater whitefish, whitefish, lenok and Hucho, taimen, all coldwater fish of the subarctic and cooler temperate regions with some sporadic endorheic populations in Central Asia. Salmon are typically fish migration, anadromous: they hatch in the shallow gravel stream bed, beds of freshwater headstreams and spend their juvenile fish, juvenile years in rivers, lakes and freshwater wetlands, migrate to the ocean as adults and live like sea ...
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Sockeye Salmon Swimming Right
The sockeye salmon (''Oncorhynchus nerka''), also called red salmon, kokanee salmon, blueback salmon, or simply sockeye, is an anadromous species of salmon found in the Northern Pacific Ocean and rivers discharging into it. This species is a Pacific salmon that is primarily red in hue during spawning. They can grow up to in length and weigh . Juveniles remain in freshwater until they are ready to migrate to the ocean, over distances of up to . Their diet consists primarily of zooplankton. Sockeye salmon are semelparous, dying after they spawn. Some populations, referred to as kokanee, do not migrate to the ocean and live their entire lives in fresh water. Classification and name origin The sockeye salmon is the third-most common Pacific salmon species, after pink and chum salmon. ''Oncorhynchus'' comes from Ancient Greek ὄγκος (''ónkos''), meaning "bend", and ῥύγχος (''rhúnkhos''), meaning "snout". The specific name ''nerka'' is the Russian name for the anad ...
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Zebra Mbuna
The zebra mbuna (''Maylandia zebra'') is a species of cichlid endemic to Lake Malawi in Africa. This species can reach a length of . It feeds on aufwuchs, a surface layer of mostly algal material that grows on rocks. This cichlid is a mouthbrooder and the female broods the eggs in her mouth for about three weeks. This fish can sometimes be found in the aquarium trade. Description The zebra mbuna has a single dorsal fin with sixteen to nineteen spines and seven to ten soft rays. The anal fin has three to four spines and six to nine soft rays. It grows to a maximum length of SL. The male fish varies in colour in different parts of its range, in some locations having a dark head, throat and belly and in others a blue head, whitish throat and grey/blue belly. In both cases the body is bright blue with up to eight grey/black bars, the dorsal fin is blue and the anal fin is blue to grey, with one to five orange to yellow spots. The female zebra mbuna is polymorphic, that is to say ...
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Blue Mbuna
The blue mbuna (''Labeotropheus fuelleborni'') is a species of cichlid found in Lake Malawi where it inhabits areas with rocky substrates. This species can reach a length of SL. This species is important to local commercial fisheries as well as being found in the aquarium trade. Some of its mottled forms are sometimes known as marmalade cat. The specific name honours the German German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ... parasitologist and military physician Friedrich Fülleborn (1866-1933). See also * List of freshwater aquarium fish species References Labeotropheus Fish described in 1926 Fish of Lake Malawi Taxa named by Ernst Ahl Taxonomy articles created by Polbot {{Pseudocrenilabrinae-stub ...
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Morphology (biology)
Morphology (from Ancient Greek μορφή (morphḗ) "form", and λόγος (lógos) "word, study, research") is the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, color, pattern, size), as well as the form and structure of internal parts like bones and organs, i.e., anatomy. This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of the overall structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Fried ...
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Cichlid
Cichlids () are a large, diverse, and widespread family of percomorph fish in the family Cichlidae, order Cichliformes. At least 1,760 species have been scientifically described, making it one of the largest vertebrate families, with only the Cyprinidae being more speciose. New species are discovered annually, and many species remain undescribed. The actual number of species is therefore unknown, with estimates varying between 2,000 and 3,000. They are native to the Neotropics, Africa (including Madagascar), the Middle East, and the Indian subcontinent, although some species have been introduced worldwide. Many cichlids, particularly tilapia, are important food fishes, while others, such as the '' Cichla'' species, are valued game fish. The family also includes many popular freshwater aquarium fish kept by hobbyists, including the angelfish, oscars, and discus. Cichlids have the largest number of endangered species among vertebrate families, most in the haplochrom ...
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Metriaclima Zebra
The zebra mbuna (''Maylandia zebra'') is a species of cichlid endemic to Lake Malawi in Africa. This species can reach a length of . It feeds on aufwuchs, a surface layer of mostly algal material that grows on rocks. This cichlid is a mouthbrooder and the female broods the eggs in her mouth for about three weeks. This fish can sometimes be found in the aquarium trade. Description The zebra mbuna has a single dorsal fin with sixteen to nineteen spines and seven to ten soft rays. The anal fin has three to four spines and six to nine soft rays. It grows to a maximum length of SL. The male fish varies in colour in different parts of its range, in some locations having a dark head, throat and belly and in others a blue head, whitish throat and grey/blue belly. In both cases the body is bright blue with up to eight grey/black bars, the dorsal fin is blue and the anal fin is blue to grey, with one to five orange to yellow spots. The female zebra mbuna is polymorphic, that is to say ...
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Labeotropheus Fuelleborni In Botanic Garden In Teplice (2)
''Labeotropheus'' is a genus of fish in the family Cichlidae endemic to Lake Malawi in eastern Africa. It includes at least 11 species, each with a number of subspecies or races. Further taxonomic work is required to determine how many species exist. These cichlids are popular ornamental fish and are ideally suited to the cichlid aquarium. Like many Malawi cichlids, these species are algal grazers. Like all cichlids from Lake Malawi these cichlids are best maintained in hard, alkaline water. This genus are best kept in aquariums with volumes greater than 120 L (31.5 gallon). The aquarium should be decorated with rocks, although caves can also be easily created from terracotta Terracotta, also known as terra cotta or terra-cotta (; ; ), is a clay-based non-vitreous ceramic OED, "Terracotta""Terracotta" MFA Boston, "Cameo" database fired at relatively low temperatures. It is therefore a term used for earthenware obj ... pots. Species There are currently 11 recognized specie ...
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Industrial Revolution
The Industrial Revolution, sometimes divided into the First Industrial Revolution and Second Industrial Revolution, was a transitional period of the global economy toward more widespread, efficient and stable manufacturing processes, succeeding the Second Agricultural Revolution. Beginning in Kingdom of Great Britain, Great Britain around 1760, the Industrial Revolution had spread to continental Europe and the United States by about 1840. This transition included going from craft production, hand production methods to machines; new Chemical industry, chemical manufacturing and Puddling (metallurgy), iron production processes; the increasing use of Hydropower, water power and Steam engine, steam power; the development of machine tools; and rise of the mechanisation, mechanised factory system. Output greatly increased, and the result was an unprecedented rise in population and population growth. The textile industry was the first to use modern production methods, and textiles b ...
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