There and back again: a natural selection tale Fledgling Theories

We usually think about natural selection making small changes, generation by generation, over long time spans. But during extreme weather events, high mortality means natural selection acts fast. How do these extreme events drive evolution? At a long term study site in Nebraska, researchers took advantage of continuous Cliff Swallow monitoring to look at the effects of three extreme weather events in the last 30 years, finding opposite selection pressures for similar climatic events. Check out the article here: "Changing patterns of natural selection on the morphology of Cliff Swallows during severe weather" (Brown et al 2018). To learn more about the long term monitoring project, check out their nice website here: https://www.cliffswallow.org/