Selection
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In evolution, the selection of traits that aid an organism's competitive capability when the population is at or near its carrying capacity.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ...
Clonal Selection
Index to this page
How B cells and T cells meet antigens
Immunological Memory and The Secondary Response
Immunological Memory in Cell-mediated Immunity
Immunological Memory and Vaccines ...
Natural Selection
Natural selection operates to produce individuals that are better adapted to their environment. It is important to keep in mind as you read below that natural selection does not act on individuals; it acts on populations.
NATURAL SELECTION
We were just talking about that. Sometimes you've got a skill that helps you survive; sometimes you don't. If you were a 500 pound bird with little tiny wings and little tiny legs, chances are you wouldn't move around too well.
natural selection
a process of differential fertility in which some genotypes, under a specific set of conditions, are more successful in producing progeny than others ...
After spending time on the islands, he soon developed a theory that would contradict the creation of man and imply that all species derived from common ancestors through a process called natural selection.
selection -- Process which favors one feature of organisms in a population over another feature found in the population.
Selection
Conditions where only mutant or recombinant cells with a particular phenotype grow and divide.
selection
The process by which the forms of organisms in a population that are better adapted to the environmental conditions increase in frequency relative to less well-adapted forms over a number of generations.
selection coefficient ...
Selection The imposition of an external force onto an organism either naturally (Natural selection) or experimentally so that some genotypes survive (and reproduce) better than others.
Jury selection. Lawyers are often criticized for using their peremptory challenges to "dumb down" the jury.
3 Selection on Courtship Behavior in Drosophila melanogaster
Crossley (1974) was able to produce changes in mating behavior in two mutant strains of D. melanogaster. Four treatments were used.
natural selection The process of differential survival and reproduction of ?tter genotypes; can be stabilizing, directional, or disruptive.
Natural selection: The concept developed by Charles Darwin that genes which produce characteristics that are more favorable in a particular environment will be more abundant in the next generation.
Natural selection. The differential survival and reproduc- tion of organisms with genetic characteristics that enable them to better utilize environmental resources.
Natural Selection: The main mechanism of evolutionary change. In a given population of organisms, there are heritable traits that enable some members to contribute a larger number of offspring than others.
Natural selection the differential reproductive success of individuals within a population‚ the ability of individuals to survive and leave the most reproducing offspring
(nata = born‚ produced) ...
Selection
Natural or artificial process that results or tends to result in the survival and propagation of some individuals or organisms but not of others with the result that the inherited traits of the survivors are perpetuated.
Selection. A change in allele frequency over time in a population
Sequential hermaphrodite. An individual that sequentially produces male and then female gametes or vice versa
Sessile. Immobile because of an attachment to a substratum ...
Selection acts on individuals, not their individual genes. Sexual reproduction increases variation by reshuffling the genetic information from parents into new combinations in their offspring. Mutations produce new alleles.
Selection favors the individuals that have the restored interaction. As a result, you have the reciprocal change in B increasing in the population, and you have a co-evolutionary step completed.
selection pressure The tendency for natural selection to occur; natural selection occurs whenever some genotypes are more fit than other genotypes.
- Selection at the cellular or callus stage of individuals possessing certain traits, such as herbicide resistance.
In vivo
- In the living organism.
Bulk selection
Selection method for self-pollinating species in cross breeding. After making the initial cross the segregating progenies are propagated till F4 to F6 without selection.
Sexual selection by a mate, fertility, and the production of sufficient progeny to replace the parents are other adaptive traits necessary for the survival of a population. Attraction to and by a mate is essential and quite varied among species.
Natural selection acts to propagate beneficial genetic traits and eliminate weaknesses. However, it is sometimes possible for a deleterious mutation to be spread throughout a population through the effect of genetic drift.
Natural selection of a population for dark coloration.
Main article: Evolution ...
The clonal selection theory of antibody diversity says:
A.
B cell precursors randomly rearrange variable coding parts of antibody genes.
Balancing selection: Selection involving opposing forces in which selective advantages and disadvantages cancel each other out.
Negative selection A selection process in T-cell development in which T cells that bind with high affinity to MHC complexes of antigen-presenting cells displaying self-peptides undergo apoptosis.
A broad definition of genetic engineering also includes selective breeding and other means of artificial selection. Genetic linkage map. A linear map of the relative positions of genes along a chromosome.
Hardy-Weinberg Law -- the concept that both gene frequencies and genotype frequencies will remain constant from generation to generation in an infinitely large, interbreeding population in which mating is at random and there is no selection, ...
Selectable markerA gene which is usually constitutively expressed and allows the selection of cells which carry it through growth on a selective medium.
Gene pool: the totality of genetic information in a given population at a given time Genetic drift: allele frequency changes in populations caused by random events rather than by natural selection, ...
Charles Darwin established evolution as a viable theory by articulating its driving force: natural selection. (Alfred Russell Wallace is commonly recognized as the co-discoverer of this concept).
This ability to provide effectively irreversible inhibition explains the selection of the serpins to control the proteolytic cascades of higher organisms. The conformational mechanism provides another advantage in its potential to modulate activity.
Biologists believe that the something that directed evolution is what is known as Natural Selection. This law says that the strongest life forms live, while those that are weaker die, and is often referred to as survival of the fittest.
Objective: To simulate the process of natural selection using various backgrounds and different colored beans.
Materials: 50 black beans
50 lima beans ...
English walnut. The walnut species (Juglans regia) used for the selection of commercial scion cultivars; origin believed in Persia (= Persian walnut).
entomophagous nematodes. Nematodes that eat insects.
Vectors are vehicles for cloning DNA. A vector provides essential sequences for replicating DNA in a host and selection antibiotic markers. Non-essential sequences are deleted to allow room for the cloning of foreign DNA.
Related ...
The study of improving a species by artificial selection; usually refers to the selective breeding of humans.
Eukaryote ...
And then third, and very important, natural selection operates upon, over those long time periods, the changes that occur, to result in emergence of species that have particular abilities to survive in a niche that the environment has provided.
evolution - a scientific theory that animals and plants originated from other preexisting types, with distinguishable differences being due to modifications in successive generations resulting from natural selection acting on variable characters ...
A change in the frequency or amplitude of the applied radio signal leads to a change in the wavelength and intensity of the diffracted light. As the radio signal can be altered rapidly, the intensity and wavelength selection are rapidly altered ...
 See also: Organ, Human, Trans, Biology, Evolution
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