Biological evolution is the heritable change in characteristics of biological populations over successive generations, driven by mechanisms such as mutation, recombination, genetic drift, gene flow, and natural and sexual selection. It operates through changes in allele frequencies within gene pools, constrained and shaped by developmental, physiological, and ecological contexts. Evolutionary processes generate adaptation, diversification, and extinction, producing hierarchical patterns from microevolutionary shifts within populations to macroevolutionary dynamics among lineages. At the molecular level, evolution involves sequence variation, genomic rearrangements, and changes in gene regulation, which collectively underlie phenotypic diversity and the emergence of complex biological organization.
When cells proliferate, genomic DNA is precisely duplicated once per cell cycle. Abnormalities in this DNA replication process can cause alterations in genomic DNA, promoting cellular aging, cancer, and genetic disorders. ...
Cell & Microbiology
Dec 2, 2025
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The dental development of modern bears does not follow the typical pattern seen in most mammals. The reason lies millions of years ago in the history of bear evolution. SNSB zoologists have identified two phases in bear evolution ...
Evolution
Dec 1, 2025
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Dogs were the first of any species that people domesticated, and they have been a constant part of human life for millennia. Domesticated species are the plants and animals that have evolved to live alongside humans, providing ...
Evolution
Nov 27, 2025
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The same brain cells linked to disorientation in Alzheimer's disease have been preserved—and even slightly increased—across millions of years of evolution.
Evolution
Nov 26, 2025
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Flight is a rare skill in the animal world. Among vertebrates, it evolved only three times: in bats, birds, and the long-extinct pterosaurs. Pterosaurs were the pioneers, taking to the skies more than 220 million years ago, ...
Evolution
Nov 26, 2025
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A collaborative study by scientists at the University of California, Riverside, and University of Southern California reports on how a process known as alternative splicing, often described as "editing" the genetic recipe, ...
Plants & Animals
Nov 24, 2025
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In nature, it is not usual for animals to be deceptive, as evolution has typically favored communication that benefits both the sender and receiver by conveying reliable information. But, there are exceptions, particularly ...
Retroviruses are viruses that have evolved the ability to write their genetic code into a cell's own DNA. The most ancient known lineage of retroviruses, foamy viruses, emerged around 450 million years ago, before animal ...
Evolution
Nov 20, 2025
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In most narratives, the story of evolution is the story of organisms emerging from the ocean and eventually populating the land. But for some species, that evolution also involved a return trip. Dozens of major mammal and ...
Evolution
Nov 20, 2025
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In most developing tissues, signals called morphogens act like lighthouses, guiding nearby cells toward their fate and telling them what to become. Each cell relies on such signals for organized structures like organs and ...
Evolution
Nov 18, 2025
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