Moving Around Flashcards
What animals have a sprawling stance? Describe this stance.
Lizards, turtles, crocodiles, and salamanders
Allthe limbs are bent and their tummy likely touches the ground at some point.
What animals have a erect stance? Describe this stance.
Mammals and birds
All limbs point straight down from their girdles
Which stance is more energy effienct: sprawling or erect? Why?
Erect because it is easier to support body weight when standing while the limbs are not bent and it allows the limb to contribute to the full length of the stride.
Did dinos stand erect or did they sprawl?
They stood erect
Cursorial limbs
limbs specially adapted for fast locomotion and they tend to have long lower leg bones. Animals with these limbs tend to either stand on their toes or on hoofs
Digitigrade posture
When an animal stands on their toes
Unguligrade posture
when an animal stands on toenails that have been modified to hoofs
Plantigrade posture
When an animal stands on our toes and flat feet simutaneously (phalanges and metatarsales are all touching the ground)
How did Ornithomimids stand?
Digitigrade stance
Graviportal limbs
Specially adapted to support extreme body weight, they tend to have large feet with fleshy pads that provide solid support and help absorb impact when walking, limbs tend to be short and when walking the joints bend as little as possible
Obligate bipeds
Animals that almost always walk and run on 2 legs
Obligate quadrupeds
animals that almost always walk and run on all 4 legs
Faculatative bipeds
Walks and all 4 legs but can raise on 2 legs to run
How did the anscestor to all dinosaurs walk?
They were an obligate biped
What group(s) of dinosaurs were obligate quadrepeds?
Sauropods, stegosaurs, and ankylosaurs
What group(s) of dinosaurs were obligate and faculatative bipeds?
Ceratopsians (depending on which species your talking about)
What group(s) of dinosaurs were obligate and obliagate bipeds?
Pachycephalosaurs and theropods
Caudofemoralis
Large muscle that pulled backward on the hindleg and is important for powering birds and crocodiles when they walk and run.
Anchored to the under surface of the ilium, to the caudal vertebrae, and to the chevrons and is attached via tendon to the femur
Trochanter
A prominance bone where the caudofemoralis muscle-ligament attaches in crocodiles and birds
Where was the theropods trochanter located and how did it benifit them?
It was high on the femur which allowed the caudofemoralis to repeatedly retract quickly allowing them to swing their legs fast when sprinting
Where was the hadrosaurs trochanter located and how did it benifit them?
It was further down the femur (as well as most other herbivours) which reduced their speed the caudofemoralis could have repeatedly retracted but it would have granted better musscle endurance (each retraction would have pulled with greater leverage) which was needed for the constant movement/ grazing
Ichnofossils
Fossils that recorded traces of biological activity such as footprints, tooth marks and burrows
Trackways
Entire series of dinosaur footprints that can be assembled
How did bipedal dinosaurs hold their body relative to the ground?
In a horazontal position and their tails off the ground
How can trackways be used to determine how fast a dino moved?
Can measure the length of the dinos strides and estimate their leg length from the proportions of their footprints (most fossils are made in mud though so we mainly know walking speed)
Ectotherm
“cold-blooded”
Animals that ajust thir internal body temp. through behaviours that depend on the temp. differenes within their enviroment
Endotherm
“warm-blooded”
Animals that regulate thir own body temps. through metabolic processes such as through burning energy to generat internal heat or sweating to lower internal tempuratures.
What is more energy coastly: ectoderm or endoderm?
Endoderm
What advantages do endoderms have over ectoderms?
They can survive cold climates, they are always ready for action (not dependent on the climate/ time of day), and they do not need to take frequent stops while maintaining a high levelof activity
Histology
The technique of slicing samples of bone into very thin sections so that the bones can be ovserved under magnification
Osteons
bone cells
Gigantothermic
Theory that the large volume but small SA of dinosaurs allowed them to be ectothermic without loosing signifigant outside heat
