Moving Around Flashcards
Name for modern animals that have a sprawling stance.
lizard, turtle, crocodile, salamander`
Name 2 (types of) animals that have an erect stance.
mammals, birds
Describe the sprawling stance.
humerus and femur project horizontally; elbows and knees strongly bent
Describe an erect stance.
humerus and femur project vertically (i.e. all limbs point straight down from their girdles)
Is it more advantageous to have an erect stance or a sprawled stance? Why? (I.e. what are the advantages?)
more advantageous: erect stance
- having the limb bones directly under the body allows the limb bones to passively support the body’s weight (without muscle strain)
- having straight limbs contributes to stride length, which increases speed (b/c stride is longer)
Why does it make sense for a lizard to have a sprawling stance?
relatively inactive; only rise to walk and run infrequently
What stance did the ancestor of all modern tetrapods assume?
sprawling stance
TRUE or FALSE: Birds and mammals evolved their erect stances independently of each other.
TRUE
What stance did dinosaurs assume?
erect stance
What are cursorial limbs specifically adapted for? Describe their strcture.
fast locomotion; long lower leg bones (below elbows and knees)
What posture describes cursorial animals that stand on their toes?
digitigrade posture
What posture describes cursorial animals that stand on their toenails/hoofs?
unguligrade posture
Name 2 modern animals with cursorial limbs and digitigrade posture.
Cheetahs and ostriches
Name 2 modern animals with cursorial limbs and unguligrade posture.
horses and antelopes
TRUE or FALSE: humans are cursorial.
FALSE
What posture do humans assume? Describe this posture.
plantigrade posture - standing simultaneously on our toes, flat of our feet, and our heels
Which dinosaurs show cursorial adaptions? What are the indications?
ornithomimid theropods; digitigrade stance and long metatarsals
What are graviportal limbs specially adapted for? Describe the bones and feet of these limbs. Are these limbs short or long? Do the joints bend a lot or very little?
adapted for: supporting extreme body weight
bones: robust and heavy
feet: large and padded
limbs: short
joints: bend very little
What is an example of a modern animal with graviportal limbs?
elephant
What is the term for an animal that walks and runs on 2 legs?
obligate bipeds
What is the term for an animal that walks and runs on 4 legs?
obligate quadrupeds
What is the term for an animal that walks on 4 legs but rises on 2 legs to run? What are some modern animal examples?
facultative bipeds; basilisk lizard, primates, kangaroos
TRUE or FALSE: The ancestor of all dinosaurs was a facultative biped.
FALSE: The ancestor of all dinosaurs was an OBLIGATE BIPED.
Which dinosaurs were obligate quadrupeds? Select all that apply
a) prosauropods
b) small ornithopods
c) sauropods
d) stegosaurs
e) pachycephalosaurs
f) hadrosaurs
g) iguanodonts
h) ankylosaurs
i) theropods
j) small ceratopsians
k) large ceratopsians
c) sauropods
d) stegosaurs
h) ankylosaurs
k) large ceratopsians
Which dinosaurs were obligate OR facultative bipeds? Select all that apply
a) prosauropods
b) small ornithopods
c) sauropods
d) stegosaurs
e) pachycephalosaurs
f) hadrosaurs
g) iguanodonts
h) ankylosaurs
i) theropods
j) small ceratopsians
k) large ceratopsians
a) prosauropods
Which dinosaurs were obligate AND facultative bipeds? Select all that apply
a) prosauropods
b) small ornithopods
c) sauropods
d) stegosaurs
e) pachycephalosaurs
f) hadrosaurs
g) iguanodonts
h) ankylosaurs
i) theropods
j) small ceratopsians
k) large ceratopsians
small ceratopsians
Which dinosaurs were obligate bipeds? Select all that apply
a) prosauropods
b) small ornithopods
c) sauropods
d) stegosaurs
e) pachycephalosaurs
f) hadrosaurs
g) iguanodonts
h) ankylosaurs
i) theropods
j) small ceratopsians
k) large ceratopsians
b) small ornithopods
e) pachycephalosaurs
i) theropods
Which dinosaurs had strong hind legs that were significantly longer than their front limbs, but despite this indication of a bipedal stance, did not actually assume a bipedal stance? Select all that apply
a) prosauropods
b) small ornithopods
c) sauropods
d) stegosaurs
e) pachycephalosaurs
f) hadrosaurs
g) iguanodonts
h) ankylosaurs
i) theropods
j) small ceratopsians
k) large ceratopsians
f) hadrosaurs
g) iguanodonts
(i.e. large ornithopods)
What is the caudofemoralis? What is its function?
what: large muscle that pulls backward on the hind leg –> ANCHOR POINT
function: power animals when they walk and run (e.g. crocodiles and birds)
Describe where in the body the caudofemoralis is anchored?
anchored to:
- the under surface of the ILIUM
- CAUDAL VERTEBRAE
- CHEVRONS
note: attached by a tendon to the FEMUR
What is the trochanter?
what: prominence of bone where caudofemoralis muscle-ligament attaches (MUSCLE ATTACHEMENT)
What can we infer about a dinosaur that has large anchor points, like the caudofemoralis?
- this dinosaur is adapted for greater hindlimb power
- probably a strong runner
What can we infer about a dinosaur whose trochanter is located high on the femur?
- high trochanter = high muscle attachment; allows caudofemoralis to repeatedly retract quickly
- probably carnivorous b/c legs can swing fast when hunting prey
What can we infer about a dinosaur whose trochanter is located low on the femur?
- low trochanter = low muscle attachment; does NOT allow caudofemoralis to repeatedly retract quickly
- probably herbivorous b/c legs don’t need to move fast (as they do not hunt prey)
- legs have much greater endurance b/c each retraction of the leg pulls with greater endurance
Why is it advantageous for herbivorous dinosaurs to have a low trochanter?
low trochanter –> greater leverage with each leg retraction –> greater endurance for moving and grazing from one patch of vegetation to the next
what is the name of fossils that records biological activity
ichnofossils
what are some examples of ichnofossils
burrows, fossil footprints and tooth marks
true or false - tooth marks are the best evidence of how a dinosaur moved
false - it is fossil footprints
what are the steps for how a footprint can be fossilized
- footprint must be made in soft mud
- mud has to dry and harden
- the footprint must be buried to protect it
true or false - dinosaur footprints are common fossils
true
what are trackways
it is an entire series of dinosaur footprints
what do trackways tell us
posture, stride length and walking speeds
true or false - bipedal dinosaurs hold their body in a vertical position
false - horizontal
briefly explain the trackways left behind by hadrosaurs and iguanodonts
they leave deep imprints by their hindfeet and shallow tracks made by front feet
true or false - longer strides enhance speed
true
how can leg lengths of dinosaurs be estimated
from the proportions of their footprints
true or false - trackways tell us about the dinosaur’s walking and running speed
false - only walking speed
_____ are animals that adjust their internal body temperature through behaviors that depend on temperature differences
ectotherms
_____ are also known as warm blooded animals
endotherms
how do endotherms warm themselves up and cool themselves down
they burn energy to generate internal heat
they sweat/pant to cool down
what is a disadvantage of being an endotherm
they must expand large amounts of energy , therefore having to consume a lot more food than ectotherms
what are the four advantages of being an endotherm
- can survive in cold climates
- they can function the same as they could in the middle of the day; not sluggish like ectotherms
- they can be out all day and night; sunny or cold
4 maintains high activity levels
why do people believe that dinosaurs are mostly endotherms
they have hair like feathers that help them hold in body heat which they gain from burning energy
briefly explain histology
a technique used to slice samples of bones into thin sections so that the internal structure of bone can be magnified
bone cells are called
a) osteoclasts
b) osteons
c) stem cells
b) osteons
do endotherms or ectotherms grow their bones more quickly
endotherms
true or false - larger dinosaurs are endothermic
false - they are gigantothermic
explain the cubic square law
when the shape increases in size, its surface area increases more slowly than the volume
using the cubic sqaure law , is this a false statement -> smaller animals have a large surface area compared to large animals
it is true
