Natural selection is the gradual, non-random process by which biological traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution. The term "natural selection" was popularized by Charles Darwin who intended it to be compared with artificial selection, what we now call selective breeding.
Variation exists within all populations of organisms. This occurs partly because random mutations cause changes in the genome of an individual organism, and these mutations can be passed to offspring. Throughout the individuals’ lives, their genomes interact with their environments to cause variations in traits. (The environment of a genome includes the molecular biology in the cell, other cells, other individuals, populations, species, as well as the abiotic environment.) Individuals with certain variants of the trait may survive and reproduce more than individuals with other variants. Therefore the population evolves. Factors that affect reproductive success are also important, an issue that Charles Darwin developed in his ideas on sexual selection, for example. Natural selection acts on the phenotype, or the observable characteristics of an organism, but the genetic (heritable) basis of any phenotype that gives a reproductive advantage will become more common in a population (see allele frequency). Over time, this process can result in populations that specialize for particular ecological niches and may eventually result in the emergence of new species. In other words, natural selection is an important process (though not the only process) by which evolution takes place within a population of organisms. As opposed to artificial selection, in which humans favour specific traits, in natural selection the environment acts as a sieve through which only certain variations can pass.
Natural selection is one of the cornerstones of modern biology. The term was introduced by Darwin in his influential 1859 book On the Origin of Species, in which natural selection was described as analogous to artificial selection, a process by which animals and plants with traits considered desirable by human breeders are systematically favored for reproduction. The concept of natural selection was originally developed in the absence of a valid theory of heredity; at the time of Darwin's writing, nothing was known of modern genetics. The union of traditional Darwinian evolution with subsequent discoveries in classical and molecular genetics is termed the modern evolutionary synthesis. Natural selection remains the primary explanation for adaptive evolution.
Other articles related to "natural selection, selection, natural":
... One theory is that because of its dark habitat, the fish embryo saves energy it would normally use to develop eyes to develop other body parts, and this developmental choice would eventually dominate the population ... This is called economical adaptation ...
... Consequently, when selection targets one allele, this automatically results in selection of the other allele as well through this mechanism, selection can have ... occur when an allele becomes more common in a population as a result of positive selection ... However, during a selective sweep, selection for a specific allele will also result in selection of neighboring alleles ...
... Darwin's own most important contribution to the theory of evolution, his theory of natural selection, is difficult to test ... in some cases, such as the famous phenomenon known as 'industrial melanism', we can observe natural selection happening under our very eyes, as it were ... Nevertheless, really severe tests of the theory of natural selection are hard to come by, much more so than tests of otherwise comparable theories in physics or chemistry ...
... With the acceptance of the natural selection idea of Charles Darwin in the 1860s, however, Lamarck's view of goal-oriented evolution, also known as a teleological process, was eclipsed ... as it is sometimes termed, is not a challenge to the theory of evolution by natural selection ... and rejecting deviations), Darwin considered variation among individuals to be natural ...
Famous quotes containing the words selection and/or natural:
“The books for young people say a great deal about the selection of Friends; it is because they really have nothing to say about Friends. They mean associates and confidants merely.”
—Henry David Thoreau (18171862)
“We do not want them to have less.
But it is only natural that we should think we have not enough.
We drive on, we drive on.
When we speak to each other our voices are a little gruff.”
—Gwendolyn Brooks (b. 1917)