CHAPTER 4 - Moving Around Flashcards
Lizards, turtles, crocodiles, and salamanders all have what is termed a __ Stance
sprawling stance.
Mammals and birds have what is termed __ Stance
erect stance
One advantage is that an erect stance positions the limb bones directly under the body. This allows
the limb bones to passively support the body’s weight without muscles having to strain.
Another advantage of erect posture is that it allows all the limb bones to contribute
the length of a stride. This improves speed, because, if every step you take is longer, you can potentially cover ground more quickly.
Birds and mammals evolved their erect stances __ of each other
independently
An erect posture is advantageous for
fast locomotion and for supporting body weight.
Cursorial limbs are
limbs specially adapted for fast locomotion. cursorial limbs are elongated.
digitigrade posture
standing on toes
stand only on toenails that have been modified into hoofs
unguligrade posture
plantigrade posture
simultaneously on our toes, the flat of our feet, and our heels
Some dinosaurs show cursorial adaptations, in particular the
ornithomimid theropods
Ornithomimids have a __stance and long __.
digitigrade Metatarsals
adapted for supporting extreme body weight.
Graviportal limbs
Animals that almost always walk and run on two legs, like birds and adult humans, are termed
obligate bipeds.
Animals that almost always walk and run on four legs, like turtles and horses, are termed
obligate quadrupeds
walk on all four legs but rise on two legs to run
facultative bipeds ex. Basalisks, kangaroo, gorillas
The ancestor of all dinosaurs was an (what type of posture)
obligate biped
Nevertheless, we classify sauropods, stegosaurs, and ankylosaurs as
obligate quadrupeds
Both of the major groups have strong hind legs that are significantly longer than their front limbs. This indicated
bipedal stance
Ichnofossils are fossils that record traces of
biologic activity (footprint, tooth marks, burrows)
Fossil footprints, tooth marks, and burrows are all examples of
ichnofossils
an entire series of dinosaur footprints are called
trackways.
The trackways of hadrosaurs and iguanodonts have deep imprints left by their ____ ____and
show that these dinosaurs carried most of their weight on their ___ ___
hind feet, hind legs
ectotherm to refer to
“cold-blooded” animals that adjust their internal body temperatures through behaviors that depend on temperature changes in the environment