directional selection

Definition and meaning of directional selection:

directional selection - a type of natural selection that removes individuals from one end of a phenotypic distribution and thus causes a shift in the distribution. The frequency of an allele is changed in a constant direction, either toward or away from fixation for that allele. Directional selection occurs when individuals at one phenotypic extreme have an advantage over individuals with more common phenotypes

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Natural selection - By effect on phenotypic composition of the population. Balancing selection - acts to maintain allelic diversity Directional selection - selects for phenotypes that depart from the mean in one direction Disruptive selection - selects for phenotypes that depart from the mean in either direction Stabilizing selection or purifying selection - selects against ...

See also:

Natural selection, Natural selection - Overview, Natural selection - Mechanisms of natural selection, Natural selection - History of the principle, Natural selection - Scope and role of natural selection, Natural selection - Impact of the idea, Natural selection - Classification, Natural selection - By effect on phenotypic composition of the population

Read more here: » Natural selection: Encyclopedia II - Natural selection - Classification

Load may be caused by selection and mutation. Genetic load - Mutational load. Load caused by mutations is known as mutational load. Genetic load - Selectional load. Selection occurs when the fitnesses of particular alleles are inequal, hence selection always exerts a load. With directional selection, the allele frequencies will tend towards an equilibrium position with the fittest allele reaching a frequency in mutation-selection balance. As mutations are rare, th ...

See also:

Genetic load, Genetic load - Definition, Genetic load - Mathematics, Genetic load - Causes of genetic load, Genetic load - Mutational load, Genetic load - Selectional load, Genetic load - Creationist criticism

Read more here: » Genetic load: Encyclopedia II - Genetic load - Causes of genetic load

Natural selection is the name Charles Darwin gave to the principal process through which new species emerge, or evolve. Combined with Gregor Mendel's theory of genetic inheritance it forms the basis for modern evolutionary theory. Darwin developed this theory by reconsidering the fact that individual members of a population or species tended to vary slightly from one other. Earlier natural scientists viewed variation negatively, as deviation from an ideal exemplar of the species. Darwin, however saw such variation as being, in princip ...

Including:

• Natural selection - Overview
• Natural selection - Mechanisms of natural selection
• Natural selection - History of the principle
• Natural selection - Scope and role of natural selection
• Natural selection - Impact of the idea

Read more here: » Natural selection: Encyclopedia - Natural selection

Vastu Shastra

Vastu Shastra is an ancient science energy flow throughout the house/office/factory that allows inflow of fresh air and natural light that promotes health, wealth, peace and happiness.

The most ancient science of architecture that goes back to the Vedic ages, it is composed of specific rules and regulations, set down by sages of those times, that an architect / builder / owner was expected to religiously follow to avoid coming under negative or evil influences. Today, it is looked upon as a highly evolved, comprehensive building philosophy in which directions and shapes are the most vital aspects of designing.

Right from the selection of site to correct slope of land down to the shape of the building, this oldest form of architecture covers nearly every aspect of construction. Not only for houses but temples, palaces, forts, offices...just about every possible form of construction. Often providing relief if not cures to physical or emotional problems simply by relocating an entrance, window or room.

Some of the important points made therein are:

• Directional Alignment
• Shape Of The Site
• Slope Of The Land Surface
• Impact of Gates At Various Locations
• Brahmasthan (Central Zone of the Building)
• The Staircase
• Inner Planning of a House
• Inner Planning of an Office
• Internal Planning of any Industrial Building

See also: Vastu Shastra

(See also: Vastu Shastra , Ayurveda, Ayurvedic Dictionary, Alternative Health, Body Mind and Soul)

The controversy often takes the tone of creationists attacking various aspects of natural history (or evolution, within this context) with proponents of mainstream science claiming that there is evidence and theoretical infrastructure in sufficient amounts to answer creationist claims. The following disciplines and observations often appear in the context of the controversy: Articles related to the creation-evolution controversy - Cosmology. The Age of the universe is disputed by many Young Ea ...

See also:

Articles related to the creation-evolution controversy, Articles related to the creation-evolution controversy - Origins, Articles related to the creation-evolution controversy - Evolution in context, Articles related to the creation-evolution controversy - Natural history, Articles related to the creation-evolution controversy - Cosmology, Articles related to the creation-evolution controversy - Geology, Articles related to the creation-evolution controversy - Evolutionary Biology, Articles related to the creation-evolution controversy - Creationism, Articles related to the creation-evolution controversy - Intelligent design, Articles related to the creation-evolution controversy - Philosophy of science, Articles related to the creation-evolution controversy - Philosophy of religion, Articles related to the creation-evolution controversy - Creation-evolution controversy

Read more here: » Articles related to the creation-evolution controversy: Encyclopedia II - Articles related to the creation-evolution controversy - Natural history

Perhaps the most radical claim of Darwin's theory of evolution through natural selection is that "elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner" have evolved out of the simplest forms of life and according to a few simple principles. It is this fundamental claim that has inspired some of Darwin's most ardent supporters—and that has provoked the most profound opposition. In addition, many theories of Artificial selection have been proposed to suggest that economic or s ...

See also:

Natural selection, Natural selection - Overview, Natural selection - Mechanisms of natural selection, Natural selection - History of the principle, Natural selection - Scope and role of natural selection, Natural selection - Impact of the idea

Read more here: » Natural selection: Encyclopedia II - Natural selection - Impact of the idea

Behavioral ecology is the study of the ecological and evolutionary basis for animal behavior, and the roles of behavior in enabling an animal to adapt to its environment (both intrinsic and extrinsic). Behavioral ecology emerged from ethology after Niko Tinbergen (a seminal figure in the study of animal behavior), outlined the four causes of behavior. These four causes can be grouped into two larger classes (ultimate causes and proximate causes). The two causes that contribute to ultimate causation are phylogenetic contingencie ...

Including:

• Behavioral ecology - References

Read more here: » Behavioral ecology: Encyclopedia - Behavioral ecology

Neurofeedback (NFB), also called neurotherapy, neurobiofeedback or EEG biofeedback, enables an individual to train brainwave activity, as measured by electrodes on the scalp, via feedback of EEG information in the form of a video display, sound or vibration. If brain activity changes in the direction desired by the therapist, a positive "reward" feedback is given to the individual, and if it regresses, either a negative feedback or no feedback is given (depending on the protocol). Rewards can be as simple as a cha ...

Including:

• Neurofeedback - History and application
• Neurofeedback - Low Energy Neurofeedback System LENS
• Neurofeedback - Scientologists Parapsychologists and Less Mainstream Users of Neurofeedback

Read more here: » Neurofeedback: Encyclopedia - Neurofeedback

The study of writing systems has developed along partially independent lines in the examination of individual scripts, and as such the terminology employed differs somewhat from field to field. The generic term text may be used to refer to an individual product of a writing system. The act of composing a text may be referred to as writing, and the act of interpreting the text as reading. In the study of writing systems, orthography refers to the method and rules of observed writing structure (literal meaning, "correct writing"), and in particular for alphabet ...

See also:

Writing system, Writing system - General properties, Writing system - Basic terminology, Writing system - History of writing systems, Writing system - Types of writing system, Writing system - Logographic writing systems, Writing system - Syllabic writing systems, Writing system - Alphabetic writing systems, Writing system - Featural writing systems, Writing system - Directionality

Read more here: » Writing system: Encyclopedia II - Writing system - Basic terminology

This is a sitemap for Oceanography - D . Click on a link and you will find multiple definitions and articles related to the word. The sitemap(s) covers over 5.184 different Oceanography terms.

dacriform, dactyloid, dactylozooid, dalton's law, damselfish, dark-field microscope, dark-spots disease, dart, darwin, darwin mounds, darwin point, darwinian evolution, data, data and information service, data management, data management and observing system interoperability, data management services, data mining, data stewardship, data warehouse, database, database management system, daughter cell, day-night sst, dbms, de facto, dead ahead, decadal, decalcification, decapod crustacean, decibel, deciduous, decomposer, decomposition, decompression, decompression chamber, decompression dive, decompression diving, decompression sickness, decompression stop, deductive reasoning, deep fore reef, deep scattering layer, deep water, deep-sea corals, definitive host, deforestation, degeneracy, degenerate character, degenerate code, degeneration, degradation, degree heating week, degree heating week accumulation, degrees of freedom, deimatic behavior, delayed fertilization, delta, delta notation, delta plain, deme, demersal, demography, demospongiae, denaturation, denatured alcohol, denaturing gradient gel electrophoresis, dendriform, dendrite, dendritic, dendrogram, denitrification, denitrify, denitrifying bacteria, dentate, denticle, denticulate, deoxyribonucleic triphosphates, deoxyribosenucleic acid, depauperate, dependent species, dependent variable, deposit, deposit feeder, depressed, depth contour, derived character, dermal, dermal flap, dermis, desalinization, designated use, desmocyte, desmoneme, determinate cleavage, detritus, detrivore, deuterostome, developed country, developing country, development, developmental response, deviation, dewlap, dextral, dgge, dhw, diadromous species, diagenesis, diagnostic characters, diapause, diaphanous, diastema, diatom, diatomaceous, dichopatric, dichopatric speciation, dichotomous key, diel, diffusion, digestion, digital versatile disc, digitiform, dimorphism, dinghy, dinoflagellate, dioecious, diopter, dioxin, dip net, diphycercal, diploid, directed fishing, directional asymmetry, directional selection, disaccharide, disciform, discoidal, discrimination, disease, disease vector, disjunct, disjunct distribution, dispersal, disphotic zone, displacement behavior, display, disputed island, disruptive coloration, disruptive selection, dissepiment, dissociation, dissolved organic carbon, dissolved oxygen, distal, distinct, distinct population segment, distributed oceanographic data system, distribution, disturbance, disulfide bond, diurnal, dive computer, dive computer algorithm, dive table, divergent evolution, diversity index, diverticulum, diving bell, division, dna, dna annealling, dna barcode, dna chip, dna fingerprinting, dna hybridization, dna library, dna ligase, dna marker, dna polymerase, dna probe, dna replication, dna sequence, do, doc, dods, dolioform, doliolaria larva, dolomite, dome shaped, dominant species, domoic acid, doppler radar, doppler shift, dorid nudibranch, dormancy, dorsal, dorsal fin, dorsoventral, dot grid, double helix, double stranded rna, doubling time, download, downstream, downwelling, dredge, dredging, drift net, drop net, drop root, drowned river, drupella, dry weight, dsrna, duct, duplex dna, dvd, dvd-ram, dychotomic growth, dynamic optical demarcation, dyne,

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The basic concept of natural selection is that "nature" (the physical and biological environment) "selects" individuals that are endowed with variant traits which improve survival and reproduction (adaptive traits) and selects against individuals burdened by traits that are unfavorable (maladaptive traits). Individuals disadvantaged by maladaptive traits might not survive until reproduction and/or reach reproduction in bad condition and only be able to produce fewer and/or lower-quality progeny, while individuals carrying favorable traits mi ...

See also:

Natural selection, Natural selection - Overview, Natural selection - Mechanisms of natural selection, Natural selection - History of the principle, Natural selection - Scope and role of natural selection, Natural selection - Impact of the idea

Read more here: » Natural selection: Encyclopedia II - Natural selection - Overview

Consider a single gene locus with the alleles , which have the fitnesses w1...wn and the allele frequencies p1...pn respectively. Ignoring frequency-dependent selection, then genetic load (L) may be calculated as: Where wmax is the maximum value of the fitnesses wSee also:

Genetic load, Genetic load - Definition, Genetic load - Mathematics, Genetic load - Causes of genetic load, Genetic load - Mutational load, Genetic load - Selectional load, Genetic load - Creationist criticism

Read more here: » Genetic load: Encyclopedia II - Genetic load - Mathematics

In biology, evolution is the process by which populations of organisms acquire and pass on novel traits from generation to generation. Its action over large stretches of time explains the origin of new species and ultimately the vast diversity of the biological world. The living species of today are related to each other through common descent, products of evolution and speciation over billions of years. The phylogenetic tree at right represents these re ...

Including:

• Evolution - Overview of evolution
• Evolution - Evidence of evolution
• Evolution - History of evolutionary thought
• Evolution - Misconceptions of modern evolutionary biology
• Evolution - Social and religious controversies
• Evolution - Science of evolution
• Evolution - Academic disciplines
• Evolution - The Modern Synthesis
• Evolution - Heredity
• Evolution - Mechanisms of evolution
• Evolution - Speciation and extinction
• Evolution - Notes and references

Read more here: » Evolution: Encyclopedia - Evolution

Balancing selection refers to forms of natural selection which work to maintain genetic polymorphisms (or multiple alleles) within a population. Balancing selection is in contrast to directional selection which favor a single allele. A balanced polymorphism is a situation in which balancing selection within a population is able to maintain stable frequencies of two or more phenotypic forms. Note balancing selection will not always result in an observable phenotypic difference beca ...

Read more here: » Balancing selection: Encyclopedia - Balancing selection

Charles Darwin's discovery of the principle of natural selection, as his explanation for the origin of species, occurred in about 1837. Over the next twenty years, he shared it with only a very small number of acquaintances, while he amassed evidence in its favor. He first outlined his theory in two unpublished manuscripts, written in 1842 and 1844. In 1858, Alfred Russel Wallace independently discovered the principle, and wrote a letter to Darwin, explaining his hypothesis. This prompted a reading, at the Linnean Society, of tracts from bot ...

See also:

Natural selection, Natural selection - Overview, Natural selection - Mechanisms of natural selection, Natural selection - History of the principle, Natural selection - Scope and role of natural selection, Natural selection - Impact of the idea

Read more here: » Natural selection: Encyclopedia II - Natural selection - History of the principle

In Chapter 4 of The Origin of Species, Darwin wrote: It may be said that natural selection is daily and hourly scrutinising, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life. We see nothing of these slow changes in progress, until the hand of time has marked the lon ...

See also:

Natural selection, Natural selection - Overview, Natural selection - Mechanisms of natural selection, Natural selection - History of the principle, Natural selection - Scope and role of natural selection, Natural selection - Impact of the idea

Read more here: » Natural selection: Encyclopedia II - Natural selection - Mechanisms of natural selection

Whether or not selection takes place depends on the conditions in which the individuals of a species find themselves. Adults, juveniles, embryos, and even eggs and sperm may undergo selection. Factors fostering selection include limits on resources (nourishment, habitat space, mates) and the existence of threats (predators, disease, adverse weather). Biologists often refer to such factors as selective pressures. Natural selection is the most familiar type of selection by name. The breeding of dogs, cows and horses, however, rep ...

See also:

Selection, Selection - Overview, Selection - Types and subtypes, Selection - Patterns of selection, Selection - Mechanisms of selection

Read more here: » Selection: Encyclopedia II - Selection - Overview

Evolution - Evidence of evolution. Main article: Evidence of evolution The process of evolution has left behind numerous records which reveal the history of different species. While the best-known of these are the fossils, fossils are only a small part of the overall physical record of evolution. Fossils, taken together with the comparative anatomy of present-day plants and animals, constitute the morphological record. By comparing the anatomies of both modern and extinct species ...

See also:

Evolution, Evolution - Overview of evolution, Evolution - Evidence of evolution, Evolution - History of evolutionary thought, Evolution - Misconceptions about modern evolutionary biology, Evolution - Social and religious controversies, Evolution - Science of evolution, Evolution - Academic disciplines, Evolution - The Modern Synthesis, Evolution - Heredity, Evolution - Mechanisms of evolution, Evolution - Speciation and extinction, Evolution - Notes and references

Read more here: » Evolution: Encyclopedia II - Evolution - Overview of evolution

Evolution - Evidence of evolution. The process of evolution has left behind numerous records which reveal the history of different species. While the best-known of these are the fossils, fossils are only a small part of the overall physical record of evolution. Fossils, taken together with the comparative anatomy of present-day plants and animals, constitute the morphological record. By comparing the anatomies of both modern and extinct species, biologists can reconstruct the lineages of those species with ...

See also:

Evolution, Evolution - Overview of evolution, Evolution - Evidence of evolution, Evolution - History of evolutionary thought, Evolution - Misconceptions of modern evolutionary biology, Evolution - Social and religious controversies, Evolution - Science of evolution, Evolution - Academic disciplines, Evolution - The Modern Synthesis, Evolution - Heredity, Evolution - Mechanisms of evolution, Evolution - Speciation and extinction, Evolution - Notes and references

Read more here: » Evolution: Encyclopedia II - Evolution - Overview of evolution