b
Pterosaurs, birds, and bats may have developed similar structures independently of each other. All of the forces are consistent in the development of flight.
Scientists are using fossil evidence of prehistoric animals called pterosaurs and the principles of Newton's second law to help develop robots with wings. These robots, called ornithopters, assist with tasks like package delivery and victim rescues during natural
disasters. The forces acting on an object in flight can be seen in Figure 1.
Figure 1: Free Body
Diagram During Flight
Lift Figure 2: Forces
Involved in Flight
Lift i
1 Resulting Force
Drag <
→ Thrust
Drag
Thrust
Weight
Direction of Flight
Weight
(pigeon: 2.94 N) Lift is the force that allows both animals and ornithopters to overcome their weight and take off from the ground. Thrust is the force that allows animals and planes to move forward horizontally while overcoming the opposing force of drag. The actions of these forces on animal flight can be seen in Figure 2. This second figure shows forward movement aboveground as a combination of lift and thrust. The "Resulting Force"
labeled in the figure is the total force that the air pushes on the bird as it flaps its wings. Pterosaurs, modern birds, and bats all had to overcome the same forces that artificial objects must overcome to achieve flight. Paleontologists know that the largest species of
pterosaur had a wingspan of more than 9 meters and weighed over 227 kilograms.
Pterosaurs flew at 113 kilometers per hour over hundreds of kilometers. Scientists have applied the principles of Newton's laws to the forces involved in flight through evolutionary studies of various pterosaur species and the analysis of the flight
patterns of modern birds and bats. The bone structures of a pterosaur, a seagull Figure 3: Bone Structures of Three Organisms
Pterosaur
Seagull
Bat
Key
• Upper arm bone
Lower arm bone
Wrist bones
Metacarpals
Fingers Which implication might be drawn from the fact that allprehistoric and modern flying vertebrates developed similar structures to support their successful flight capabilities?
a
Pterosaurs, birds, and bats evolved directly from a single species of reptile. Their identical flight structures developed sequentially from the pterosaur to the bat.
b
Pterosaurs, birds, and bats may have developed similarstructures independently of each other. All of the forces are consistent in the development of flight.
c
Pterosaurs, birds, and bats developed over time in identical ecosystems and environments. These environments influence the forces of flight for these animals
d
Pterosaurs, birds, and bats developed flight at the same time. Thiswas their single effective adaptation for locating and trapping prey.
1 answer