Arthropods were the first animals to venture onto land and spread over the earth. Their body plan allowed them to diversify and adapt to every environment, including the air, inventing new ways to extract oxygen from air rather than water. Some arthropods, like dragonfly larvae, live in freshwater, and then through metamorphosis, develop wings and take to the air. Flight was a major adaptation for arthropods opening up new realms: three-fourths of all the animals on earth are flying insects. And spiders evolved an ingenious method for catching the flying insects. Arthropods provide essential services to ecosystems and humans both as recyclers and pollinators.