Evolution: development of flying not understood (Introduction)

by David Turell , Wednesday, October 24, 2018, 15:33 (2009 days ago) @ David Turell

Flying close to surface helps:

https://cosmosmagazine.com/biology/flying-close-to-ground-saves-energy

"Flying animals save energy – and lots of it – by flying close to the ground, researchers have found, adding evidence for one of two competing theories of the evolution of flight.

"A group of scientists led by Christoffer Johansson, a biologist at Lund University in Sweden, have demonstrated that Daubenton’s bats (Myotis daubentonii) save 29% of their aerodynamic power through the so-called “ground effect”, suggesting that flight developed as an extension of surface-based activities.

"The ground effect occurs when the land or water below a flying object increases the air pressure beneath its wings, thus reducing the amount of energy needed to stay aloft.

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"Our measurements show that the ground effect saves animals twice as much energy as models have suggested,” Johansson says.

"The research could shed light on the evolution of flight, which is still a mystery to scientists. One theory, known as trees-down, suggests that animals began flying by jumping through the air between branches and trees. Another theory, known as ground-up, holds that animals began flying first by running and jumping along the ground (or, for insects, along water), and that wings evolved to help elongate the distances thus covered.

"The new research supports the latter theory.

“'This is obviously speculation,” says Johansson, “but if flapping animals save more energy than we previously believed by flying close to the ground, then the ground up theory becomes more probable: animals began to fly by first running and jumping on the ground with flapping precursors to wings.”

"The study points out that flying is the most energy-expensive form of locomotion in the animal kingdom, so any savings would be evolutionarily favoured.

"Many species of bats specialise in flying low, or skimming, over water to feed on insects, which researchers now see is a “sweet spot” of behaviour."

Comment: Certainly flying is a great way to get around, and from an eating standpoint, from the air is a great way to spot prey. Flying is done differently in bats, in birds and in insects indicating it appeared at different times in different ways and represents the concept of 'convergence', which in some minds is another word for design.