Comparative Aspects of Locomotion Flashcards
Bipedal Hopping Energy Efficiency
* Energy efficient (use tail when they are going slow)
* once it starts hopping, energy needed actually decreases (especially as speed increases!)
Why is bipedal hopping so efficient energy wise?
Can increase stride length without increasing hop frequency.
What acts to create bipedal hopping?
Active contraction of the muscles
Pull from extension of the stifle
CALLED POWER TRANSFER
What are some adaptations to bipedal hopping?
* Tibia to femur ratio
* Long and strong tail
* Short forelimbs
*Short cervical vertebrae and long thoracic vertebrae (compared)
What are some changes in the stifle joint in kangaroos and the foot?
* Fibrocartilaginous (she called it fibrous) patella because there are so many forces pulling on it all the time
* Cushions in the middle of the stifle joint- in the middle of the menisci- they help to observe shock from the epicondyles of the femur pushing and turning on it
* Their foot- highly keratinised skin on palmar foot and fat pads
What is the most important contributor to energy efficiency in bipedal hopping?
Ability to increase stride length without increase in stride frequency
Flying vertebrates- quick discussion of the physics of flying
Life must overcome weight and propulsion must overcome drag
Adaptations to fly?
* Light skeleton: birds and bats have short tails AND small light legs…. birds have hollow bones, reduced digits, short tail, no teeth (not bats)
* Firm trunk- wobbling produces extra drag: fused vertebrae- synsacrum- caudal thoracic, lumbar, and sacrum AND Notarium. Sacrum occurs in all birds. (not in bats). Birds and bats have reduced sternum and they both have broad flat ribs…. birds- coracoid, bats have a clavical
* efficient in how you produce and use power- because flying has a high energy cost- in birds if they flex and extend elbow- it flexes and extends their carpus at the same time, in bats- when their shoulder flexes or extends- same thing happens to their elbow and carpus (AUTOMATION OF MOVEMENT). Increased SURFACE AREA on sternum. On birds called a carina (latin for the keel of the ship).
Structure of bird wings
Discuss structure of bat wings
What are the main two muscles for flight in a bird?
Pectoral muscle (downward stroke)
Supracoracoid muscle (upward stroke)
How many muscles do bats use in flowing? And what is the second big difference?
17 muscles
Point of rotation during flight in the wing. Bats have the pectoral muscle and same insertions (sternum and proximal humerus). But serratus, clavodelt and subscapularis. Rather than scapula firmly attached and still- moves down against the body wall- point of rotation NOT in the shoulder in the STERNUM. WHERE THE CLAVICAL JOINS THE STERNUM. (vs. birds which is shoulder joint)
primary vs. secondary swimmer examples
Fish (pretty much all they do) vs. mammals
Otarids vs. Phocids seals
Otarid seals- sea lions as an example. They have external ears. You can see their ears.
Phocids- true seals- no external ears
Physics of swimming
Overcome weight and drag of the water (less things sticking out- shorter external appendages, the better- the ones you do have- nice and flat…. also nice and slippery– slimey surface on scales of fish… marine mammals- no hair or very short hair)
Undulatory Swimmers
Undulatory- wave like swimming- Nemo and Dory
***In fish-
* spinal column is in the center (not dorsal) in fish
* segmented muscles- series of them. They contract sequentiall
***In mammals-
*they use axial and apaxial muscles to create propulsion
Oscillatory Swimming
Paired appendages- wide and flat- move them up and down, little or no body movement
