Natural selection
hideNatural selection is the process by which heritable traits that make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations. It is a key mechanism of evolution.
The natural genetic variation within a population of organisms means that some individuals will survive and reproduce more successfully than others in their current environment. For example, the peppered moth exists in both light and dark colors in the United Kingdom, but during the industrial revolution many of the trees on which the moths rested became blackened by soot, giving the dark-colored moths an advantage in hiding from predators. This gave dark-colored moths a better chance of surviving to produce dark-colored offspring, and in just a few generations the majority of the moths were dark. Factors which affect reproductive success are also important, an issue which Charles Darwin developed in his ideas on sexual selection.
Natural selection acts on the phenotype, or the observable characteristics of an organism, but the genetic (heritable) basis of any phenotype which gives a reproductive advantage will increase in frequency over the following generations (see allele frequency). Over time, this process can result in adaptations that specialize organisms 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.
Natural selection is one of the cornerstones of modern biology. The term was introduced by Darwin in his groundbreaking 1859 book On the Origin of Species, in which natural selection was described by analogy to artificial selection, a process by which animals 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.
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News tagged with natural selection
Caught in the act: Scientists find butterflies splitting into two species
Nov 05, 2009 |
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(PhysOrg.com) -- Breaking up may actually not be hard to do, say scientists who've found a population of tropical butterflies that may be on its way to a split into two distinct species.
Genes drive behaviour, but culture can select genes: study
Oct 28, 2009 |
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Culture, not just genes, can drive evolutionary outcomes, according to a study released Wednesday that compares individualist and group-oriented societies across the globe.
Are humans still evolving? Absolutely, says new analysis of long-term survey of human health
Oct 19, 2009 |
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Although advances in medical care have improved standards of living over time, humans aren't entirely sheltered from the forces of natural selection, a new study shows.
Time in a bottle: Scientists watch evolution unfold
Oct 18, 2009 |
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A 21-year Michigan State University experiment that distills the essence of evolution in laboratory flasks not only demonstrates natural selection at work, but could lead to biotechnology and medical research ...
High mortality rates may explain small body size
Oct 05, 2009 |
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A new study suggests that high mortality rates in small-bodied people, commonly known as pygmies, may be part of the reason for their small stature. The study, by Jay Stock and Andrea Migliano, both of the University of Cambridge, ...
Why Female Water Buffalo Have Horns but Impala Do Not?
Sep 17, 2009 |
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(PhysOrg.com) -- The reason some female hoofed animals have horns while others do not has long puzzled evolutionary biologists, even the great Charles Darwin. But now a survey of 117 bovid species led by Ted Stankowich, professor ...
Robots Reveal Insights into Evolution
Sep 16, 2009 |
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(PhysOrg.com) -- In an ironic twist to our understanding of life, robots may offer a greater degree of realism for studying some of the intricacies of natural selection and evolution than real organisms offer. ...
Study examines the evolutionary fate of 'useless' traits
Sep 08, 2009 |
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What happens when traits no longer give creatures a competitive edge?
Ego City: Cities organized like human brains
Sep 03, 2009 |
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(PhysOrg.com) -- Cities are organized like brains, and the evolution of cities mirrors the evolution of human and animal brains, according to a new study by researchers at Rensselaer Polytechnic Institute.
Anthropologist researches evolution of Darwin’s theory
Sep 02, 2009 |
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(PhysOrg.com) -- New research by University of Notre Dame anthropologist Agustin Fuentes, published recently in the European journal Anthropology Today, states that although Darwin’s basic ideas still form t ...
Mice living in sandy hills quickly evolved lighter coloration
Aug 27, 2009 |
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In a vivid illustration of natural selection at work, scientists at Harvard University have found that deer mice living in Nebraska's Sand Hills quickly evolved lighter coloration after glaciers deposited ...
Researchers find first-ever 'wanderlust gene' in tiny bony fish
Aug 05, 2009 |
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(PhysOrg.com) -- A gene previously associated with physical traits is also dictating behaviour in a tiny fish widely regarded as a living model of Darwin's natural selection theory, according to a University ...
After dinosaurs, mammals rise but their genomes get smaller
Jul 27, 2009 |
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(PhysOrg.com) -- Evidence buried in the chromosomes of animals and plants strongly suggests only one group -- mammals -- have seen their genomes shrink after the dinosaurs' extinction. What's more, that trend continues today, ...
All of us -- from slime mould to MPs -- are born to cheat
Jul 24, 2009 |
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(PhysOrg.com) -- Organisms are genetically programmed to cheat the system and have to be policed to stop them putting their needs ahead of society and thus threatening its survival, say scientists.
'Invisible hand' guides evolution of cooperative turn-taking, research shows
Jul 09, 2009 |
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It's not just good manners to wait your turn -- it's actually down to evolution, according to new research by University of Leicester psychologists.
