Flight Flashcards
How is lift created
Air flowing around the wing creates low pressure on the upper surface. This sucks the wing upwards generating lift
What is drag
Force exerted on an object moving through a fluid
Which way is drag orientated
Direction of fluid flow
How is drag minimised
Streamlining
What is thrust
Force induced in the direction of flight, opposing the drag force
How is thrust created
Wing flapping
Why are large flight muscles needed
To create thrust to overcome the drag force - this is done by the flapping of wings
What four groups has flight evolved in
Insects
Pterosaurs
Birds
Bats
What structures are the wings of birds and bats
Analogous
Why are bird and bat wings analogous
Evolved through convergent evolution
What is convergent evolution
Process whereby organisms not closely related independently evolve similar traits as a result of adapting to similar environments or niches
Explain the ground up scenario
Walking animals evolved to fly
Trees down scenario
Walking animals could climb trees
Jumped from tree to tree
Evolved to fly instead
Why did flight evolve
Avoid predators Eat flying prey Move between places Access to new niches Hind legs used as weapons
What implies that flight is advantageous
Diversity of insects birds and bats that use it
How did the pterosauria evolve to fly
Ground up
When did the pterosauria live
200-65 MYA
Describe the anatomy of the pterosauria
Keeled sternum
Preroid bone
Wing supported by elongated 4th digit
Describe the anatomy of pteranodon ingens
7k wingspans Wing bones thick but hollow Large brain and optic nerves Large crested head Comparatively small body 12kg
How did the pteranodon ingens fly
By soaring
What modern day bird is the pteranodon ingens related to
The pelican
What did the pteranodon ingens use it’s beak for
Scooping fish
How did flight in aves evolve
Ground up
Similarities between aves and pterosaurs
Hollow bones
Stout humerus
Keeled sternum
Differences between aves and pterosaurs
Bird wing supported by radius
Ulna
Modified wrist bones
What are the modified wrist bones in birdrs called
Carpometacarpus
Describe the avian skeleton
Keeled sternum Unicinate processes on ribs Bones of pelvis fused Limbs moved by muscles near centre of body Beak and gizzard Tail vertebrate reduced
Describe the structure of flight feathers in aves
Stiff
Flint
Interlinked by barbules to form an efficient areofoil
Why are flight feathers of aves interlinked by barbules
To form an efficient aerofoil
What’s the oldest bat fossil
Eocene
How old is the oldest bat fossil
55 MYA
How did flight in bats evolve
Tree down
What are bats related to
Dermoptera (flying lemurs)
What do bats have a close affinity with
Primates
What are Chiroptera
Bats
Describe the anatomy of a Chiroptera
Membranous wing supported by the arm and digits 2-5
Keeled sternum - fused clavicles, scapula and sternum
Calamari which supports the uropatagium from the heel
Why do bats have high camber
To generate lift
Why do bats have low stall speed and high manoeuvrability
Due to high camber and low wing loading
What is wing
loading
Mass/area of wing
How much do bats weigh
5-10g
Disadvantages of flight
Costs lots of energy
Constrains body size and morphology
What struthiformes
Ostrich emus etc
What are the 4 convergent adaptations obtained by pterosaurs birds and bats
Arefoil
Light body weight
Keeled sternum
Reduction/fusion of bones
What are the wings of bats homologous to
Human arms
What is the pendactyl limb inherited from
Common ancestor of all tetrapods
Pterosaur bird and bat wings are analogous as wings but homologous as
Forelimbs
Which forces need to be overcome to achieve flight
Drag and weight
