Birds take wing

Found at Solnhofen in 1861, two years after On the Origin of Species, Archaeopteryx immediately became the single most important piece of evidence for evolution by natural selection. Later finds from Liaoning in China have shown that feathers were widespread among theropods long before flight, and probably arose for insulation or display. Flight was therefore a repurposing of something that already existed. Birds are the only dinosaur group to survive the impact, and with around 11,000 species are today more diverse than mammals.