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Outbreeding Depression
In biology, outbreeding depression happens when crosses between two genetically distant groups or populations result in a reduction of fitness. This is particularly likely if the subspecies have different habitats or if no genetic exchange has occurred, except in the distant past. The concept is in contrast to inbreeding depression, although the two effects can occur simultaneously. The risks of outbreeding are on par with the risks of inbreeding, and these risks sometimes limits the potential for genetic rescue or augmentations. Indeed, studies that report hybridization in mammals find resulting negative consequences about 4 times more likely than positive consequences. Outbreeding depression can occur between an invasive population and a native populations; hybridization can result in extinction of the native species or the loss of native adaptations. Outbreeding depression considered post-zygotic response because outbreeding depression is noted usually in the performance of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outbreeding Depression
In biology, outbreeding depression happens when crosses between two genetically distant groups or populations result in a reduction of fitness. This is particularly likely if the subspecies have different habitats or if no genetic exchange has occurred, except in the distant past. The concept is in contrast to inbreeding depression, although the two effects can occur simultaneously. The risks of outbreeding are on par with the risks of inbreeding, and these risks sometimes limits the potential for genetic rescue or augmentations. Indeed, studies that report hybridization in mammals find resulting negative consequences about 4 times more likely than positive consequences. Outbreeding depression can occur between an invasive population and a native populations; hybridization can result in extinction of the native species or the loss of native adaptations. Outbreeding depression considered post-zygotic response because outbreeding depression is noted usually in the performance of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Recombination
Genetic recombination (also known as genetic reshuffling) is the exchange of genetic material between different organisms which leads to production of offspring with combinations of traits that differ from those found in either parent. In eukaryotes, genetic recombination during meiosis can lead to a novel set of genetic information that can be further passed on from parents to offspring. Most recombination occurs naturally and can be classified into two types: (1) ''interchromosomal'' recombination, occurring through independent assortment of alleles whose loci are on different but homologous chromosomes (random orientation of pairs of homologous chromosomes in meiosis I); & (2) ''intrachromosomal'' recombination, occurring through crossing over. During meiosis in eukaryotes, genetic recombination involves the pairing of homologous chromosomes. This may be followed by information transfer between the chromosomes. The information transfer may occur without physical exchange (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cichlid
Cichlids are fish from the family Cichlidae in the order Cichliformes. Cichlids were traditionally classed in a suborder, the Labroidei, along with the wrasses ( Labridae), in the order Perciformes, but molecular studies have contradicted this grouping. The closest living relative of cichlids is probably the convict blenny, and both families are classified in the 5th edition of ''Fishes of the World'' as the two families in the Cichliformes, part of the subseries Ovalentaria. This family is both large and diverse. At least 1,650 species have been scientifically described, making it one of the largest vertebrate families. 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. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anole Lizard
Dactyloidae are a family of lizards commonly known as anoles () and native to warmer parts of the Americas, ranging from southeastern United States to Paraguay. Instead of treating it as a family, some authorities prefer to treat it as a subfamily, Dactyloidae, of the family Iguanidae. In the past they were included in the family Polychrotidae together with '' Polychrus'' (bush anoles), but the latter genus is not closely related to the true anoles. Anoles are small to fairly large lizards, typically green or brownish, but their color varies depending on species and many can also change it. In most species at least the male has a dewlap, an often brightly colored flap of skin that extends from the throat/neck and is used in displays. Anoles share several characteristics with geckos, including details of the foot structure (for climbing) and the ability to voluntarily break off the tail (to escape predators), but they are only very distantly related, anoles being part of Igu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poison Dart Frog
Poison dart frog (also known as dart-poison frog, poison frog or formerly known as poison arrow frog) is the common name of a group of frogs in the family Dendrobatidae which are native to tropical Central and South America. These species are diurnal and often have brightly colored bodies. This bright coloration is correlated with the toxicity of the species, making them aposematic. Some species of the family Dendrobatidae exhibit extremely bright coloration along with high toxicity, while others have cryptic coloration with minimal to no amount of observed toxicity. The species that have great toxicity derive this feature from their diet of ants, mites and termites. However, other species that exhibit cryptic coloration, and low to no amounts of toxicity, eat a much larger variety of prey. Many species of this family are threatened due to human infrastructure encroaching on their habitats. These amphibians are often called "dart frogs" due to the Native Americans' use of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limnetic Zone
The limnetic zone is the open and well-lit area of a freestanding body of freshwater, such as a lake or pond. Not included in this area is the littoral zone, which is the shallow, near-shore area of the water body. The key difference between the littoral zone and the limnetic zone is the presence of rooted plant growth. The floor under the limnetic zone cannot sustain plant growth due to a lack of sunlight for photosynthesis. In extremely shallow bodies of water, light may penetrate all the way to floor even in the deepest center parts of the lake. In this situation, there is an absence of a limnetic zone and the littoral zone spans the entire lake. Together, these two zones comprise the photic zone. There are two main sources of oxygen to the photic zone: atmospheric mixing and photosynthesis. Oxygen is dissolved when air interacts with water on the surface, and is increased with wave and wind action. Unlike the profundal zone, the limnetic zone is the layer that receives suf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthic Zone
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms (e.g., bacteria and fungi) as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Description Oceans The benthic region of the ocean begins at the shore line ( intert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stickleback
The sticklebacks are a family of ray-finned fishes, the Gasterosteidae which have a Holarctic distribution in fresh, brackish and marine waters. They were thought to be related to the pipefish and seahorses but are now thought to be more closely related to the eelpouts and sculpins. Taxonomy The stickleback family, Gasterosteidae, was first proposed as a family by the French zoologist Charles Lucien Bonaparte in 1831. It was long though that the sticklebacks and their relatives made up a suborder, the Gasterosteoidei, of the order Gasterostiformes with the sea horses and pipefishes making up the suborder Syngnathoidei. More recent phylogenetic work has shown that the Gaterosteoidei is more closely related to the Zoarcoidei and the Cottoidei, which means that this taxon would belong in the order Scorpaeniformes. but in other phylogenetic classifications it is treated as the infraorder Gasterosteales within the suborder Cottoidei or as a sister clade to the Zoarcales in the orde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Largemouth Bass
The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, but widely introduced elsewhere. It is known by a variety of regional names, such as the widemouth bass, bigmouth bass, black bass, bucketmouth, largies, Potter's fish, Florida bass, Florida largemouth, green bass, bucketmouth bass, Green trout, gilsdorf bass, Oswego bass, LMB, and southern largemouth and northern largemouth. The largemouth bass is the state fish of Georgia and Mississippi, and the state freshwater fish of Florida and Alabama. Taxonomy The largemouth bass was first formally described as ''Labrus salmoides'' in 1802 by the French naturalist Bernard Germain de Lacépède with the type locality given as the Carolinas. Lacépède based his description on an illustration of a specimen collected by Louis Bosc near Charle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pink Salmon
Pink salmon or humpback salmon (''Oncorhynchus gorbuscha'') is a species of anadromous fish in the salmon family. It is the smallest and most abundant of the Pacific salmon. The scientific species name is based on the Russian common name for this species ''gorbúša'' (горбуша), which literally means ''humpie''. Description In the ocean, pink salmon are bright silver fish. After returning to their spawning streams, their coloring changes to pale grey on the back with yellowish-white belly (although some turn an overall dull green color). As with all salmon, in addition to the dorsal fin, they also have an adipose fin. The fish is characterized by a white mouth with black gums, no teeth on the tongue, large oval-shaped black spots on the back, a v-shaped tail, and an anal fin with 13-17 soft rays. During their spawning migration, males develop a pronounced humped back, hence their nickname "humpies". Pink salmon average 4.8 pounds (2.2 kg) in weight. The maxim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaiian Duck
The Hawaiian duck (''Anas wyvilliana'') or koloa is a species of bird in the family Anatidae that is endemic to the large islands of Hawaii. Taxonomically, the koloa is closely allied with the mallard (''A. platyrhynchos''). It differs in that it is monochromatic (with similarly marked males and females) and non-migratory. As with many duck species in the genus ''Anas'', Hawaiian duck and mallards can interbreed and produce viable offspring, and the koloa has previously been considered an island subspecies of the mallard. However, all major authorities now consider this form to be a distinct species within the mallard complex. Recent analyses indicate that this is a distinct species that arose through ancient hybridization between mallard and Laysan duck (''Anas laysanensis''). The native Hawaiian name for this duck is ''koloa maoli'' (meaning "native duck"), or simply koloa. This species is listed as endangered by the IUCN Red List of Threatened Species, and its population trend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Zealand Grey Duck
The Pacific black duck (''Anas superciliosa''), commonly known as the PBD, is a dabbling duck found in much of Indonesia, New Guinea, Australia, New Zealand, and many islands in the southwestern Pacific, reaching to the Caroline Islands in the north and French Polynesia in the east. It is usually called the gray duck in New Zealand, where it is also known by its Maori name, . Taxonomy The Pacific black duck was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's ''Systema Naturae''. He placed it with all the other ducks, geese and swans in the genus ''Anas'' and coined the binomial name ''Anas superciliosa''. Gmelin based his description on the "Supercilious duck" that had been described in 1785 by the English ornithologist John Latham in his ''A General Synopsis of Birds''. The naturalist Joseph Banks had provided Latham with a water-colour drawing of the duck by Georg Forster who had accompanied Jam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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