Geology exam 3 dinosaurs lecture

what makes a dino a dino (also what isnt a dinosaur)

when limbs are fully rotated under the body

acetabulum=hole in your hip socket (they cannot swing their legs out to the side, only from front to back ALL DINO HAVE THIS)

advanced mesotarsal ankle ( it pulls the ankle up to walk on toes)

sauropod

tiny head, giant body

quadrupedal

herbivores

sauropod (adaptation) for plant eating

they have very round teeth. they essentially stripped leaves from trees and swallowed them whole

gastrolith (sauropods) adaptation

gatro=stomach

lith= stone

if swallowed, they sit in your stomach and grind up plants. birds do this too

theropods

pretty small about the size of a chicken or turkey

long, sharp teeth

jaws sutured together

hollow bones

bipedal

mostly carnivorous

vegetarian theropod

claws for stripping leaves

no sharp teeth-no ability to eat meat

ornithischians (adaptation)

two types of teeth-sharp ones for grabbing, duller ones for grinding (like your molars)

they have a special jaw joint that allows their jaws to move side to side

what is sexual dimorphism

differences between male and females

egg laying tissue found in 1 theropod ever, the only proof we have at this point

the more comp. there is for mates, the more dimorphism there will be

how does sexual dimorphism vary in in organisms with different mating habits

ex. a male peacock will have very large feathers to attract females

also mating calls

why small arms in t-rex. What might this suggest

they were fearsome hunters

smaller arms are likely paedomorphic. meaning those limbs retained juevenile characteristics into adulthood

how could you survive a t-rex attack and why

run in zigzags bc/

what are some examples of defense and/or mating in dinosaurs. why the frill on triceraptops

ceratopsians (having horns)

stegosauria: row of spines along back and tail (ostederms)

thagomizer (spikey tail)

horn covered beak

stegosaurus: male and female

never found in adult pairs

have been found in parent-child fossil pairs

less sexual dimorphism (not too much differences between male and females

why did feathers likely evolve

for warmth

camouflage

protection

exaptation

when a trait develops for one purpose but is used for another

ex. feathers on birds

feathers were originally for camofaluge then were later used for flight

favorite dinosaur

her favorite dinosaur is the parasaurolophus

what is the geological evidence for the extinction? what caused it

an asteroid hit

not all dinos are extinct

layer of iridium (formed in stellar explosions) (rare earth element) (means if it were in crust, it came from a meteorite/ asteroid)

shocked quartz: forms when quartz crystals undergo a pulse of great pressure/impact, but do not melt. the shock causes unique microstructures

tektites (larger glass beads/unusual shapes/textures): formed when rocks are instantaneously melted and splashed out as big globs of molten glass and cooled while spinning in the air.

occured in north america

thick layer of all of this dating back to 65 million years ago

chicxulub crater off of the yucutan peninsula

short/ long terms effects of impact

short: acid rain, cooling from the sun being blocked out, tsunamis

long term: greenhouse gases causing intense warming