Pterosaurs were the first animals after insects to evolve powered flight—not just leaping or gliding, but flapping their wings to generate lift and travel through the air. They evolved into dozens of species.
Although many animals can glide through the air, pterosaurs, birds and bats are the only vertebrates that have evolved to fly by flapping their wings. All three groups descended from animals that lived on the ground, and their wings evolved in a similar way: their forelimbs gradually became long, bladelike and aerodynamic.