Urban ecologists have demonstrated that cities are functioning ecosystems. It follows then that species living in these contexts should participate in and experience the same suite of biological processes, including evolution, that have occupied scientists for centuries in more "natural" contexts. In fact, urban ecosystems with myriad novel contexts, pressures, and species rosters provide unprecedentedly potent evolutionary stimuli. Here, we present the case for studying adaptive evolution in urban settings. We then review and synthesize techniques into a coherent approach for studying adaptive evolution in urban settings that combines observations of phenotypic divergence, measurements of fitness benefits of novel genetically based phenotypes, and experimental manipulations of potential drivers of adaptation. We believe that studying evolution in urban contexts can provide insights into fundamental evolutionary biology questions on rate, direction, and repeatability of evolution, and may inform species and ecosystem service conservation efforts.

Hurricanes are catastrophically destructive. Beyond their toll on human life and livelihoods, hurricanes have tremendous and often long-lasting effects on ecological systems. Despite many examples of mass mortality events following hurricanes, hurricane-induced natural selection has not previously been demonstrated. Immediately after we finished a survey of Anolis scriptus-a common, small-bodied lizard found throughout the Turks and Caicos archipelago-our study populations were battered by Hurricanes Irma and Maria. Shortly thereafter, we revisited the populations to determine whether morphological traits related to clinging capacity had shifted in the intervening six weeks and found that populations of surviving lizards differed in body size, relative limb length and toepad size from those present before the storm. Our serendipitous study, which to our knowledge is the first to use an immediately before and after comparison to investigate selection caused by hurricanes, demonstrates that hurricanes can induce phenotypic change in a population and strongly implicates natural selection as the cause. In the decades ahead, as extreme climate events are predicted to become more intense and prevalent, our understanding of evolutionary dynamics needs to incorporate the effects of these potentially severe selective episodes.

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Summary Body size often varies among insular populations relative to continental conspecifics – the ‘island rule’ – and functional, context‐dependent morphological differences tend to track this body size variation on islands. Two hypotheses are often proposed as potential drivers of insular population differences in morphology: one relating to diet and the other involving intraspecific competition and aggression. We directly tested whether differences in morphology and maximum bite capacity were explained by interisland changes in hardness of both available and consumed prey, and levels of lizard‐to‐lizard aggression among small‐island populations. Our study included 11 islands in the Greek Cyclades and made use of a gradient in island area spanning five orders of magnitude. We focused on the widespread lizard Podarcis erhardii. We found that on smaller islands, P. erhardii body size was larger, head height was larger relative to body size, and maximum bite capacity became proportionally stronger. This pattern in morphology and performance was not related to differences in diet, but was highly correlated with proxies of intraspecific aggression – bite scars and missing toes. Our findings suggest that critical functional traits such as body size and bite force in P. erhardii follow the predictions of the island rule and are changing in response to changes in the competitive landscape across islands of different sizes.