Biological variation in populations is the process by which genetic and phenotypic differences arise, are maintained, and change in frequency among individuals within a species. It results from the combined action of mutation, recombination, gene flow, genetic drift, and natural and sexual selection, acting on genomes across generations. At the population level, this variation underlies differences in traits such as morphology, physiology, behavior, and fitness-related characteristics, and is quantified using measures like allele frequencies, heterozygosity, and quantitative trait distributions. Population-level biological variation provides the raw material for adaptive evolution and influences population dynamics, speciation potential, and responses to environmental change.
For more than a century, scientists have sought to reconstruct human evolution using diverse lines of evidence, including fossils, genetic variation across populations and ancient DNA. Building on these approaches, researchers ...
Evolution
Jul 24, 2026
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100
Birds can inhabit various environments with different climates and temperatures, ranging from cold polar regions to scorching hot deserts. To survive and thrive in these very different environments, they need to effectively ...
In mammals, males are usually stronger and more competitive than females. Males also show greater inequality in reproductive success—the number of offspring they produce—than females. In spotted hyenas, the opposite is true: ...
Evolution
Jul 23, 2026
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87
Honeybees do not like cold weather. When temperatures dip, they can become sluggish and unable to fly. But no matter the conditions in the outside world, they try to keep their hives close to a comfortable 34°C–36°C (93°F–97°F). ...
Scientists have long thought humans have a uniquely difficult birth compared with other primates. And it's true that, from an evolutionary perspective, we face an obstetrical dilemma. As we evolved to walk on two feet, our ...
Plants & Animals
Jul 16, 2026
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10
For researchers on the hunt for the genetic roots of disease, the cost of deep whole-genome sequencing makes it challenging to conduct large genetic studies involving thousands of participants, which are needed to reveal ...
Molecular & Computational biology
Jul 12, 2026
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75
A new international study led by researchers at the University of Oulu, Finland, shows that wolves living in different parts of the world are not anatomically identical. Their skulls differ in shape and size according to ...
Plants & Animals
Jul 7, 2026
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11
A new study, published July 6, 2026, in the journal Nature Communications, suggests that two of the best-known trends in human evolution—brain growth and the reduction in the size of the face and jaw—may be far less attributable ...
Evolution
Jul 6, 2026
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1400
A new study of wild bats reveals that an animal's immune system is shaped by more than its need to fight infections. Researchers from the University of Maryland have found that sex, age and competition for mates influence ...
Evolution
Jul 1, 2026
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10
A new analysis supports the previously overlooked "brain lag" hypothesis—the idea that, in some primate lineages, the evolution of larger body size preceded the evolution of larger brain size—while also building on that hypothesis ...
Evolution
Jul 1, 2026
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39
