Lesson 14 (Decoding Dinosaurs) Flashcards
who was the first person to describe and illustrate a dinosaur femur?
Robert Plot in 1677
Who first identified the teeth, jaws and limbs of the megalosaurus
William Buckland, 1824
What did dinosaurs evolve from
archosaurs
Who named the group of fossils dinosaurs?
Sir Richard Owen, 1842
When did dinosaurs evolve from archosaurs
Late triassic, 230MA
what are the two groups of dinosaurs? how are they defined?
Saurischia and Ornithischia
- defined based on structure of pelvis
Qualities of saurischia
- ‘lizard hipped’ dinosaurs
- included trex and diplodocus
- pubis bone points forward
qualities of ornithischia
- ‘bird hipped’ dinosaurs
- backward pointing pubis bone
- included hadrosaurus and triceratops
What is an example of a Archosaurus
Euparkeria
What does th new theory published in March 2017 regarding dinosaur evolution suggest
Includes Traditional ornithischians and theropods with Saurischia and Ornithoscelida groups
Example and traits of eary theropod
- Eoraptor
- bipedal carnivore
- insectivore
With respect to morphology, what are the three main ways in which Coelophysis differ from their reptile ancestors?
List 3 characteristics that contributed to Coelophysis being an excellent predator.
Using a chronological list of 3 steps, explain what is believed to have happened during the rapid burial of Coelophysis at Ghost Ranch.
What approximate speed is thought to be a normal walking pace for an adult Coelophysis? (in km/hr)
What approximate speed is thought to the fastest that an adult Coelophysis could have run? (in km/hr)
What size were fully grown Coelophysis relative to most adult dinosaurs?
What size were fully grown Coelophysis relative to most adult dinosaurs?
What specific evidence suggests that Coelophysis may have been a cannibal? Why does further study bring this hypothesis in to question? (Hint: be specific)
What are some possible explanations for the ‘Predator Gap’, where there are virtually no medium sized predators in the fossil record?
How much did “small” predatory dinosaurs weigh?
How long did T. rex potentially live for?
If the two medium predator skeletons identified by some as Nanotyrannus, do end up belonging to a juvenile T. rex, what new information does this give us about T. rex?
What does this info suggest about the prey each of these different aged T. rex groups have hunted?
How might this answer help explain the gap in medium sized predators?
how can you get a better idea of the overall appearance of a dinosaur?
reconstructing skeleton and adding muscles to model
how do you find the texture of a dinosaurs skin? what do they suggest?
skin impressions have been found on dinosaur species - indicate scale like pattern
what was the original purpose of feathers?
display not flight
which dinosaur originally had feathers for display?
Caudipteryx
What produces colour?
Melanosomes
What colour does a round shaped melanosome produce?
russet
what colour do elongated melanosomes produce
black/grey
qualities of sinosaurpteryx? how did this help it
which dinosaur had a dashing ginger pattern and a striped tail?
- used potentially for mating or fighting display
qualities of anchiornis?
black white and red coloured
qualities of psittacosaur?
-small bipedal dinosaur (size of gazelle)
- common in asia in the early cretaceous
- greenish
what is the order jurassic, cretaceous, triassic
triassic, jurassic, cretaceous
Describe the color pattern called ‘countershading’.
light on underside, darker top
What does the shading on the animal’s body suggest about where it lived? Why?
environment with less light, such as a forest (better for camouflage)
Why was this type of shading likely to protect against predators?
counter illuminates shadows on the body, allowing an animal to appear optically flat
- protected psittacosaurus against predators who use shadow patterns to determine shape, like humans do
How could further research in to color patterns help us better understand predators?
examining different colour patterns in different environmentsWhen did ‘protofeathers’ likely first arise?
to see which best suits the colour pattern
what does psittacosaurus mean
parrot lizard
When did ‘protofeathers’ likely first arise?
Did some genera of the therapods include members with feathers?
Did some genera of the ornithischians include members with feathers?
What is Phylogenetic Bracketing?
Why did dinosaurs potentially develop feathers? (What are some of the potential functions of feathers?)
which dinosaur developed the ability to fly independent of birds?
microraptor
which dinosaurs burrowed underground
Oryctodromeus cubicularis
why did some dinosaurs burrow?
cold environments
- highlights that dinosaurs were not all restricted to warm environments
which marine reptiles are commonly labeled as dinosaurs? (but are not)
ichthyosaurs, mosasaurs and plesiosaurs
are there any aquatic dinosaurs?
spinosaurus is suggested to be semi aquatic
Could the sail of Spinosaurus have been used as a heat regulator or as storage for fat? Why, or why not?
What else could the sail of Spinoceras have been used for other than the functions suggested in Question 1?
What kind of environment did Spinosaurus live in, and what did the animal eat?
List THREE pieces of evidence from its skeleton that the researchers used to determine the answer to Question 3.
How do the researchers explain the presence of so many large predators in the Kem Kem beds when there are so few large terrestrial plant eaters?
How is it possible to find Spinosaurus fossils in the Sahara Dessert today?
what is one way to determine if a dinosaur is a carnivore or herbivore?
teeth (piercing flesh vs grinding plants)
what is a unique feature about apatosaurus
large - had to feed all the time
peg/spoon like teeth which would strip vegetation off plants (did not chew or swallow, instead gulped down vegetation)
what are gastroliths
polished stones found in the stomach of dinosaurs to help break down tough vegetable material
did smaller dinosaurs hunt in packs?
trackways suggest smaller dinosaurs travelled together although it is difficult to tell if they hunted in a coordinated way
difference between allosaurus and trex
allosaurus had longer arms
what was unique about allosaurus brain? what does this mean?
- similar to crocodillian brain
- large olfactory bulbs (keen sense of smell)
- small cerebrum
allosaurus probably smelled something and made a grab for it, similar to a crocodile. Not a lot of brain processing happening
how can you examine brains to discover traits
- compare and contrast to modern animals
- determine the size of certain brain sections
what is the olfactory bulbs
smell centers
how does allosaurus qualities explain the Cleveland Lloyd Dinosaur Quarry where a majority of the 79 dinosaurs found were allosaurs?
- Area was a muddy watering hole and it would attract and trap dinosaurs.
- Allosaurs would be attracted by the smell of rotting flesh and then become trapped themselves
Who is “Big Al” and in what geological period did he live?
In what type of sedimentary environment was he preserved?
Who are Big Al’s closest living relatives?
How long did it take for an allosaur to grow to full size?
Were allosaur brains more like birds or alligators?
Other than brain shape, what also suggests that allosaur feeding behavior may have been similar to that of alligators?
What do paleontologists think caused Big Al’s death?
what is egg mountain?
eggs and eggshells found in western montana
what does maiasaura mean
caring mother lizard
what evidence is there to suggest that dinosaurs cared for their young?
- egg mountain (dinosaur shells + juveniles found in nest created by Maiasaura)
- fossils (family fossil, daycare dinosaur with 40 juveniles)
what is an ectotherm
- cold blooded, requires sun to warm up
what is an endotherm
- warm blooded, generates own body heat
what factors can you use to determine an endotherm vs an ectotherm
- posture and gate
- bone structure
- oxygen isotopes
- predator prey relationships
how does posture and gate determine an endothermic vs an ectothermic creature? Is this reliable?
ectotherms have sprawling gate
endotherms have limbs tucked inside
- not necessarily, no direct link between posture and metabolism
how does bone structure determine an endothermic vs an ectothermic creature? Is this reliable?
endotherms have more channels for blood vessels than ectotherms
- not necessarily, crocodiles have endothermic bone structure but are ectothermic
how does O16:O18 isotope ratios determine an endothermic vs an ectothermic creature? Is this reliable?
it does not - it would be assumed that they would be stable and even in a warm blooded creature but this is not the case
do endotherms of ectotherms have to eat more food
endotherms to maintain high body temp
how does the predator to prey ratio determine endotherms vs ectotherms?
- ecosystem cannot sustain as much endothermic top predators as ectothermic as endothermic eat more
- predator/prey ratio can give answers to predator but not to prey
