Learning Objective 4.1
describe a sprawling stance?
animal’s humerus and femur project horizontally, with elbows and knees strongly bent
eg. turtles, salamanders, lizards, and crocdiles
Learning Objective 4.1
describe an erect stance
animal’s humerus and femur project vertically, sucha that all limbs point straight down from their girdles
Learning Objective 4.1
what are the 2 advantages of an erect stance?
- passively support body weight
- animals who do a sprawling stance often rest on their belly
-active animals like mammals and birds need a more efficient stance - allow for all limbs to contribute to the length of the stride
- improves spped and the longer step you take, you can potentially cover ground more quickly
Learning Objective 4.1
what stance is the stance of the ancestor that all modern tetrapod share?
what is the stance of dinosaurs
- sprawling ancestors
- birds and mammals evolved their erect stances independently of each other
- dinosaurs stood erect
Learning Objective 4.2
describe cursorial limbs
define: digitigrade and unguligrade
- are specially adapted for fast locomotion
tend to have very long lower leg bones - they often stand on their toes - digitigrade posture
- or stand on toenails that have been modified into hoofs - unguligrade
- example dino is ornithomimid theropods
Learning Objective 4.2
describe graviportal limbs
adapted for supporting extreme body weight
- limbs have bones that are robust and heavy, large feet, short and joints bend as little as possible
Learning Objective 4.2
define: obligate bipeds, obligate quadrupeds and facultative bipeds
- aniamls that almost always walk and run on two legs
- animals that almost always walk and run on four legs
- animals that walk on all four but rise on two legs to run
Learning Objective 4.2
The ancestor all dinosaurs was an? and classify the groups of dinosaurs to each category
obligate biped, obligate quadrupeds or faculative bipeds
obligate biped
- obligate quadrupeds: stegosaurs, sauropods, ankylosaurs, older ceratopsians
- obligate biped: theropods, pachycephalosaurs, small ornithopods
- faculative and obligate biped - smaller ceratopsians
- facultative biped - Hadrosaurs and iguanodonts
learning objective 4.3
define ichnofossils
fossils that record traces of biologic acitivty
- fossil footprints, tooth marks, and burrows
learning objective 4.4
define warm and cold-blooded; ectotherms and endotherms
ectotherms - animals that adjust their internal body temperatures through behaviours that depend on the temp differences within their environment
- ex. lizards bask in the sun or on top of hot rocks
endotherms- regulat their own body temps through metabolic processes
- ex. sweating or panting
learning objective 4.3
what are the 3 advantages of being an endotherms
- can survive in cold climates
- alwasy ready for action; function the same throughout the day in comparison to extotherms that may be sliggish and easy predators to avoid or easy prey to catch
- do not need to take frequent stops and can maintain high activity levels
