Evolutionary Physiology of Animal Flight

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"Peaking" Into the World of Flight

Ever wondered about what initiated the ability of flight among insects and vertebrates? About how the creatures take off and venture into their flight? Well if “yes” was an answer to one of the questions (or even if it wasn’t), Flight is the place to find the answers.

Oxygen, Forces & Flight

Oxygen? Check. Forces? Check. Ready for flight? Check.

"It's all About Oxygen"

Oxygen has a role in flight? Of course! ... A motion and a changing ability, flight in insects and vertebrates have developed and evolved for years. The amount of oxygen in the atmosphere is a significant component to the initiation of flight. Departing from the normal atmospheric oxygen concentration of 21%, oxygen concentration once heightened to a hyperoxic 35% and plunged down several times to a hypotonic 15% during the Phanerozoic Eon (around 600 MYa to 0 MYa). The time frame reflects an increase in oxygen levels of about four times enabling a stronger foundation of flight among insects and vertebrates due to oxygen’s rich abundance of energy.

“Flying Against F-O-R-C-E-S”

Fly. Flying. Flew. Flight. What comes to mind? Well, a creature with wings and some flapping is quite the possibility. Yet, there is much more to the word and motion. Through an animal’s perspective, flying is not always smooth. There are two key forces to remember: lift and drag. Lift is the pressure created and exerted vertically on a flying creature. Lift can equal or exceed the pressure of gravity and is surely achieved once a creature flies. Drag is the horizontal force acting against the creature, and it branches off to two types: pressure drag and viscous drag. Pressure drag (also known as inertial drag) is the force that is part o...

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...ding, then a more effective method of escape is to jump and glide, or fly away. An increased air density and oxygen concentration would make gliding, and therefore flight, easier. In turn, selection would favor the traits that made gliding and flight easier. This selection would perpetuate the ability to glide and fly in the species. This is currently the most feasible explanation for the evolution of flight.

Resources

"Bernoulli's Principle". Think Quest. Aug 1999. 14 Nov 2007 http://library.thinkquest.org/27948/bernoulli.html

Dudley, Robert. "The Evolutionary Physiology of Animal Flight: Paleobiological and Present Perspectives". Annual Review of Physiology. 2000. 63:135-55. 27 Aug 2007 http://arjournals.annualreviews.org

"Theory of Flight". Massachusetts Institute of Technology. 16 Mar 1997. 14 Nov 2007 http://web.mit.edu/16.00/www/aec/flight.html

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