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Cogradient Variation
Countergradient variation is a type of phenotypic plasticity that occurs when the phenotypic variation determined by a biological population's genetic components opposes the phenotypic variation caused by an environmental gradient. This can cause different populations of the same organism to display similar phenotypes regardless of their underlying genetics and differences in their environments. To illustrate a common example known as countergradient growth rate, consider two populations. The two populations live in different environments that affect growth differently due to many ecological factors, such as the temperature and available food. One population is genetically predisposed to have an increased growth rate but inhabits an environment that reduces growth rate, such as a cool environment, and thereby limits the opportunities to take full advantage of any genetic predisposition. The second population is genetically predisposed to have a decreased growth rate but inhabits an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotypic Plasticity
Phenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompasses all types of environmentally induced changes (e.g. morphological, physiological, behavioural, phenological) that may or may not be permanent throughout an individual's lifespan. The term was originally used to describe developmental effects on morphological characters, but is now more broadly used to describe all phenotypic responses to environmental change, such as acclimation (acclimatization), as well as learning. The special case when differences in environment induce discrete phenotypes is termed polyphenism. Generally, phenotypic plasticity is more important for immobile organisms (e.g. plants) than mobile organisms (e.g. most animals), as mobile organisms can often move away from unfavourable environments. Nevertheless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Silverside
The Atlantic silverside (''Menidia menidia''), also known as spearing in the northeastern United States, is a small species of fish that is one of the most abundant fish species present in estuarine habitats along the Atlantic coast of North America. It is a common subject of scientific research because of its sensitivity to environmental changes. According to the IUCN Red List, this species is stable and has no major threats to its populations, so it is marked Least Concern. Despite being an extremely common species, most individuals die after one year once they migrate offshore, but a few will make it to two years. The fish is mostly translucent, with white coloring on the anterior end of the body and brown speckling on the top of the head, posterior scales on the back, and near the jaw. A distinctive silver band runs the length of the fish, next to the lateral line. Their mouths are large compared to other ''Menidia'' species, and their first dorsal fins are placed more post ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cogradient Variation
Countergradient variation is a type of phenotypic plasticity that occurs when the phenotypic variation determined by a biological population's genetic components opposes the phenotypic variation caused by an environmental gradient. This can cause different populations of the same organism to display similar phenotypes regardless of their underlying genetics and differences in their environments. To illustrate a common example known as countergradient growth rate, consider two populations. The two populations live in different environments that affect growth differently due to many ecological factors, such as the temperature and available food. One population is genetically predisposed to have an increased growth rate but inhabits an environment that reduces growth rate, such as a cool environment, and thereby limits the opportunities to take full advantage of any genetic predisposition. The second population is genetically predisposed to have a decreased growth rate but inhabits an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spartina Anglica
''Sporobolus anglicus'' (common cordgrass) is a hybrid-derived species of cordgrass that originated in southern England in about 1870 and is a neonative species in Britain. It was reclassified as ''Sporobolus anglicus'' after a taxonomic revision in 2014, but but its previous name, ''Spartina anglica'' is still in common usage. It is an allotetraploid species derived from the hybrid ''Sporobolus × townsendii'', which arose when the European native cordgrass '' Sporobolus maritimus'' (small cordgrass) hybridized with the introduced American '' Sporobolus alterniflorus'' (smooth cordgrass). Common cordgrass is a herbaceous perennial plant growing tall. Its foliage consists of round stems that are yellowish green in spring and summer, and turns light brown in autumn and winter. The leaves are long, and broad at the base, tapering to a point. It produces flowers and seeds on only one side of the stem. The flowers are a yellowish-green, turning brown by the winter. Invasive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carex Aquatilis
''Carex aquatilis'' is a species of Carex, sedge known as water sedge and leafy tussock sedge. It has a Circumboreal Region, circumboreal distribution, occurring throughout the northern reaches of the Northern Hemisphere. It grows in many types of mountainous and arctic habitat, including temperate coniferous forest, alpine tundra, alpine meadows, tundra, and wetlands. There are several varieties of this species, and it is somewhat variable in appearance. It produces triangular stems reaching heights between and , and generally does not form clumps as some other sedges do. It grows from a dense rhizome network which produces a mat of fine roots thick enough to form sod, and includes aerenchyma to allow the plant to survive in low-oxygen substrates like heavy mud. The inflorescence bears a number of spikes with one leaflike bract at the base which is longer than the inflorescence itself. The fruits are glossy achenes, and although the plant occasionally reproduces by seed, most of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saccharina Latissima
''Saccharina latissima'' is a brown alga (class Phaeophyceae), of the Family (biology), family Laminariaceae. It is known by the common names sugar kelp, sea belt, and Devil's apron, and is one of the species known to Japanese cuisine as kombu. It is found in the north Atlantic Ocean, Arctic Ocean and north Pacific Ocean. Description ''Saccharina latissima'' is a yellowish brown colour with a long narrow, undivided blade that can grow to long and wide. The central band is dimpled while the margins are smoother with a wavy edge, this is to cause greater water movement around the blades to aid in gas exchange. The frond is attached to the rock by stout rhizoids about 5 mm in diameter in the Intertidal zone, intertidal and sublittoral zones by a claw-like holdfast (biology), holdfast and a short, pliable, cylindrical stipe. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Fence Lizard
The eastern fence lizard (''Sceloporus undulatus'') is a medium-sized species of lizard in the family Phrynosomatidae. The species is found along forest edges, rock piles, and rotting logs or stumps in the eastern United States. It is sometimes referred to as the prairie lizard, fence swift, gray lizard, gravid lizard, northern fence lizard or pine lizard. It is also referred to colloquially as the horn-billed lizard. One of its most notable behaviors is that of its escape behavior when encountering fire ants, which have been known to invade and negatively affect many of their populations. Taxonomy The generic name, ''Sceloporus'', is derived from the Greek ''skelos''/σκελος, meaning "leg", and the Latin ''porus'', meaning "hole", referring to the enlarged femoral pores found in this genus of lizards. The specific name, ''undulatus'', is Latin for "wave", referring to the transverse dark crossbars on the backs of these lizards. Liddell HG, Scott R (1980). ''Greek-Englis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood Frog
''Lithobates sylvaticus'' or ''Rana sylvatica'', commonly known as the wood frog, is a frog species that has a broad distribution over North America, extending from the boreal forest of the north to the southern Appalachians, with several notable disjunct populations including lowland eastern North Carolina. The wood frog has garnered attention from biologists because of its freeze tolerance, relatively great degree of terrestrialism (for a ranid), interesting habitat associations (peat bogs, vernal pools, uplands), and relatively long-range movements. The ecology and conservation of the wood frog has attracted research attention in recent years because they are often considered "obligate" breeders in ephemeral wetlands (sometimes called " vernal pools"), which are themselves more imperiled than the species that breed in them. The wood frog has been proposed to be the official state amphibian of New York. Description Wood frogs range from in length. Females are larger tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila Melanogaster
''Drosophila melanogaster'' is a species of fly (an insect of the Order (biology), order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly", "pomace fly", or "banana fly". In the wild, ''D. melanogaster'' are attracted to rotting fruit and fermenting beverages, and are often found in orchards, kitchens and pubs. Starting with Charles W. Woodworth's 1901 proposal of the use of this species as a model organism, ''D. melanogaster'' continues to be widely used for biological research in genetics, physiology, microbial pathogenesis, and Life history theory, life history evolution. ''D. melanogaster'' was the first animal to be Fruit flies in space, launched into space in 1947. As of 2017, six Nobel Prizes have been awarded to drosophilists for their work using the insect. ''Drosophila melanogaster'' is typically used in research owing to its rapid life cycle, relatively simple genetics with on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properties, and its behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code (its genotype) and the influence of environmental factors. Both factors may interact, further affecting the phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and again in his 1982 book '' The Extended Phenotype'' suggested that one can regard bird nests and other built structures such as caddisfly larva cases and beaver dams ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithobates Clamitans
''Lithobates clamitans'' or ''Rana clamitans'', commonly known as the green frog, is a species of frog native to eastern North America. The two subspecies are the bronze frog and the northern green frog. These frogs, as described by their name, typically have varying degrees of green heads. These frogs display significant acts of territoriality, with males being the primary actors. Male green frogs use this technique against other male frogs in addition to other intruders that might have interest in nearing their territory. Territoriality also plays a role in mating, as females favor males who are strong in this field and exhibit strong mating calls. Male green frogs use four different types of breeding calls to attract potential female mates. Predators of the eggs of green frogs include beetles, water bugs, and water scorpions. Adult frogs are typically threatened by several types of birds. Taxonomy ''Lithobates clamitans'' is a member of the true frog family Ranidae and ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Levins
Richard Levins (June 1, 1930 – January 19, 2016) was a Marxist biologist, a population geneticist, biomathematician, mathematical ecologist, and philosopher of science who researched genetic diversity, diversity in human populations. Until his death, Levins was a university professor at the Harvard T.H. Chan School of Public Health and a long-time activism, political activist. He was best known for his work on evolution and complexity in changing ecosystem, environments and on metapopulations. Levins also had written on philosophical issues in biology and scientific modelling, modelling. One of his influential articles is "The Strategy of Model Building in Population Biology". He has influenced a number of contemporary philosophers of biology. Levins often boasted publicly that he was a 'fourth generation Marxist' and often had said that the methodology in his ''Evolution in Changing Environments'' was based upon the introduction to Marx's ''Grundrisse'', the author's notes (n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
