The special adaptations of birds contribute to two essentials for flight: more power and less weight. Explain how each of the following contributes to one or both of these two essentials: feathers, skeleton, muscle distribution, digestive system, circulatory system, respiratory system, excretory system, reproductive system.
Feathers are very light weight and hollow, but, posses remarkable toughness which allows them to lift themselves off the ground. The skeleton is also light weight, delicate and laced with air cavities. The muscle distribution is used for power. The muscles are used in lift for flight as well as for grasping things with their talons. They have a power full digestive system which allows them to digest quickly thus allowing them to be able to get away from predators because they don't have to eat slowly. The circulatory system is a complete seperation of respiratory and systemic circulations and their heart is four chambered with a strong ventricular walls. In their respiratory system air sacs are connected the lungs in such a way that most of the inspired air bypasses the lungs and flows directly into the posterior air sacs which serve as reservoirs for fresh air, thus making their respiratory system the most efficient of any terrestrail. Birds have no urinary bladder so all the waste comes from the same place allowing them to empty their wastes all at the same time. They lay eggs instead of having live births which allows them to protect their young from a distance. This also means that they don't have to have their young by their side at all times.
