How fast does evolution occur

By looking at global studies of our DNA, we can see evidence that natural selection has recently made changes and continues to do so. Though modern healthcare frees us from many causes of death, in countries without access to good healthcare, populations are continuing to evolve.

Survivors of infectious disease outbreaks drive natural selection by giving their genetic resistance to offspring. Our DNA shows evidence for recent selection for resistance of killer diseases like Lassa fever and malaria. Selection in response to malaria is still ongoing in regions where the disease remains common. Humans are also adapting to their environment. Mutations allowing humans to live at high altitudes have become more common in populations in Tibet , Ethiopia , and the Andes. The spread of genetic mutations in Tibet is possibly the fastest evolutionary change in humans, occurring over the last 3, years.

This rapid surge in frequency of a mutated gene that increases blood oxygen content gives locals a survival advantage in higher altitudes, resulting in more surviving children.

Diet is another source for adaptations. Evidence from Inuit DNA shows a recent adaptation that allows them to thrive on their fat-rich diet of Arctic mammals. Materials provided by McGill University. Note: Content may be edited for style and length. Science News. Bell and Gonzalez discovered that a population was more likely to adapt quickly through evolutionary rescue if: There was slow environmental deterioration, i.

These populations were then able to adapt to environmental stress that would have been sufficient to eradicate their ancestors. It was connected by dispersal, i. This population then had a much greater probability of avoiding extinction after a rapid and severe perturbation.

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