Wings Enable Glide

brown and green lizard on brown tree bark

Biological Strategy

Common flying dragon

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Move in/Through Gases

Living systems must move through gases (which are less dense than liquids and solids) such as those in the earth’s atmosphere. The greatest challenge of moving in gases is that because the living system is heavier than the gas, it must overcome the force of gravity. Moving efficiently in this light medium presents unique challenges and opportunities for living systems. As a result, they have evolved countless solutions to optimize drag and increase lift so that they can stay aloft and take advantage of variable currents. Additionally, they must overcome gravity when moving from a liquid or solid into the air. The fairyfly, the smallest known insect, is a tiny wasp that must move through the air. To the wasp, air feels like a heavy liquid and to move through it, it uses special feathery oars rather than wings.

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Reptiles

Class Reptilia (“creeping”): Lizards, crocodiles, turtles, snakes

Reptiles retain some of the key characteristics that first enabled vertebrates to live permanently on land. They have dry skin covered in scales made of keratin that help prevent water loss. (Amphibians still need to stick close to water to keep their skin moist.) Many reptiles reproduce by laying eggs that are watertight and have a yolk, so eggs can develop on land while staying moist and nourished. Reptiles are also ectotherms, meaning they don’t produce their own body heat. This means they burn through energy much more slowly than “warm blooded” creatures of the same size. It also means that they need to keep warm to keep active, which is why you might see them spending a seemingly inordinate amount of time simply basking in the sun.

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Special elongated ribs of the flying dragon lizard enable it to glide via adjustable membranes that act as 'wings'.

“The ‘wings’ of this spectacular lizard are made from membranes stretched between a series of specially elongated ribs that act as struts. The end result bears uncanny resemblance to early designs for aircraft wings, but the lizard’s version is far more sophisticated since its wings can be opened and closed at will. The lizard’s flattened body improves its aerodynamics, and its slender tail acts as a counterbalance. On average, each flight carries it roughly 25 feet (8m)” (Downer 2002:30)

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