Men and women differ in obvious and less obvious ways—for example, in the prevalence of certain diseases or reactions to drugs. How are these connected to one's sex? Weizmann Institute of Science researchers recently uncovered ...
May 4, 2017
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Evolution has shaped the human race, with University of Queensland researchers finding signatures of natural selection in the genome that influence traits associated with fertility and heart function.
Apr 18, 2018
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Developed countries, with greater access to healthcare, experience much higher rates of cancer incidence than the world's "worse off" countries, according to new research from the University of Adelaide.
Oct 6, 2017
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Are women who have twins more fertile? While previous studies concluded they are, a detailed analysis of more than 100,000 births from pre-industrial Europe by an international team of scientists shows they are not. The results ...
May 24, 2022
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Epigenetics – how gene expression is regulated by temporary switches, called epi-marks – appears to be a critical and overlooked factor contributing to the long-standing puzzle of why homosexuality occurs.
Dec 11, 2012
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(Medical Xpress)—For the first time, researchers have discovered that disease-causing mutations in mitochondrial DNA (mtDNA) are common in healthy individuals, according to a Cornell study published July 7 in the Proceedings ...
Jul 8, 2014
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There's nothing wrong with being a little weird. Because we think of psychological disorders on a continuum, we may worry when our own ways of thinking and behaving don't match up with our idealized notion of health. But ...
Feb 20, 2018
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Twin births aren't exactly common. In humans, they occur in one to three percent of all births.
Aug 2, 2022
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Scientists investigating the evolution of the virus that causes COVID-19 say that its mutation seems to be directed by human proteins that degrade it, but natural selection of the virus enables it to bounce back. The findings ...
Jul 22, 2020
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Scientists at Dana-Farber Cancer Institute have developed a drug that potently neutralizes SARS-CoV-2, the COVID-19 coronavirus, and is equally effective against the Omicron variant and every other tested variant. The drug ...
Dec 7, 2022
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Natural 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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