Page 128 - The Origin of Birds and Flight

126 The Origin of Birds and Flight

THE PERFECT FLIGHT TECHNOLOGY IN LIVING THINGS
In many ways, it is impossible to account for birds’ ideal structure for
flight in terms of evolution. The structure of the wing as described in the
last chapter is just one of these impossibilities. Flight is based on a very
complex system, and to control it, the bird must have a nervous system ca-
pable of controlling its muscles flawlessly. In this nerve-muscle control, aft-
er the muscles contract with commands they receive from the nerve cells,
they transmit back signals that report their position. When a bird rises,
glides in the air or descends to earth, this feedback system goes into action
to create the required aerodynamics.
When we examine how animals adapt to their environments, we real-
ize that the mechanisms’ in many creatures’ bodies go far beyond the tech-
nological achievements that we humans are so proud of. Flight is one of
the most striking examples. If a small airplane were as efficient as a plov-
er, it could fly for 56 kilometers (34.796 miles) on a single liter of petrol. At
present, however, such economical flight is no more than a designers’ and
engineers’ dream.
Birds’ perfect aerodynamic structure, which amazes scientists, can be
seen in every detail of their bodies:
* Feathers which, in proportion to their weight have a very strong but
also flexible and light structure,
* Powerful wings controlled by powerful muscles,
* Flexible, strong but also light and hollow bones,
* A unified skeletal structure,
* A large, powerful heart and a circulatory system with high levels of
blood pressure and the pigment myoglobin, which facilitates respiration,
* A respiratory system with air sacs extending as far as the bones,
* A digestive system that ensures high body temperature and sugar
accumulation,
* The collection of waste fluids in the body for the purpose of prevent-
ing water and weight loss,
* A navigation system, the secrets of which have still not been under-
stood,