Exam 3 Flashcards by devon barclay

Dryptosaurus, discovered in Mantua Township NJ in 1866, was the first known member of which theropod clade?

Tyrannosauroidea

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[T/F] a group of theropods is still alive today

true

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What is a probable function of the extremely long, thin claws on the hands of therizinosaurian theropods?

They used them to grab onto branches/food

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it suggests that dinosaurs may have died due to blindness caused by cataracts or the explosion of a nearby star in a supernova event. Why are these ideas not viable scientific hypotheses?

It would suggest that it affected every living dinosaur and not the other mammals living during that time which caused only the dinosaurs to die of blindness and no other mammals. It also is not testable or parsimonious.

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A spike in enrichment of the element iridium has been found in the K/Pg boundary layer around the globe. How is this iridium important toward resolving what caused the extinction of non-avian dinosaurs?

This accumulation in the layer of rock indicates dust from an extraterrestrial source, an asteroid.

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[T/F] extinction can only be caused by a rapid, catastrophic event

false

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What defines a feather as a “flight feather”?

it is strong due to interlocking barbules within its structure

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[T/F] Most dinosaur skeletons mounted in museums are complete skeletons of single individuals.

false

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How are most feathers preserved in the fossil record?

as flat, carbonized films

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[T/F] Several dozen news stories are published every day about dinosaurs.

true

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Scientific evidence supports which of these behaviors in some dinosaurs?

burrowing, flight, cannibalism, migration

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What percentage of species are extinct?

99.9%

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Extinction of the dinosaurs Categories Medical problems example?

disease, parasite epidemic, blindness, senility
(scientific thinking…)
is it testable? is it parsimonious

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Extinction of the dinosaurs Categories Caused by other lifeforms (mammals or plants) example?

starvation, deforesation, outcompeted by mammals

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Extinction of the dinosaurs Categories atmospheric changes example?

extreme climate change / fluctuations. wildfires, high C02

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Extinction of the dinosaurs Categories geological causes example?

global cooling

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Extinction of the dinosaurs Categories extraterrestrial causes example?

sunspots, comet/ asteroid impact, cosmic radiation

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Extinction of the dinosaurs Categories Caused by other lifeforms (mammals or plants) example?

starvation, deforestation, outcompeted by mammals

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Extinction of the dinosaurs Categories Caused by other lifeforms (mammals or plants) example?

starvation, deforestation, outcompeted by mammals

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What is an impact of the crater?

Acid rain globally, bust blocks sunlight

What was the primary killer in the mass extinction of the dinosaurs?

starvation - the base of the food chain (plants) was taken out
dead

How do we know its from the crater? (evidence it was astroid)

shocked minerals, iridium anomaly, glass spherules, tsunami deposits

What is shocked metamorphism?

crossing patterns of fractures or deformation lines

what is iridium anomaly?

a metal common in asteroids but rare in earth’s crust
accumulation in a layer of rock suggests dust from an extraterrestrial source
a spike in iridium concentrations at the K/pg found worldwide (including fossil park)

what are glass spherules?

heat of impact liquifies asteroid and the impacted rock - molten rock launched out of the crater - cools and solidifies rapidly as it’s falling through the atmosphere as tiny glass beads called spherules

What are the taphonomic requirements for 3D preservation?

1.) burial very soon after death 2.) shallow burial limits crushing 3.) (usually) mineralization

what is change in form/ anatomy through your life

ontogeny

what is tiny bones encasing the eye

Sclerotic ring

what is protein that makes up beaks claws, horns, feathers (& your fingernails)

Keratin

why are museum dinosaurs smaller than how they were in real life?

because they forget to account for cartilage

how is skin preserved?

through mineralization

how is color preserved?

preserved melanosomes identified by microscopy? = pigment cells

what should you do when you can't identify what it looks like?

go to Phylogenetic Inference - inferring probable anatomy based on phylogenetic relationships - example - Though not preserved, the skull of Dreadnoughts probably looked like that of other tiranosauriform

why is it inferred there was theropod pack hunting?

their high EQ/"intelligence" - mass-death bonebeds of multiple individuals

what evidence of predator-prey relationships are there?

1.) Teeth embedded in bones 2.) Gut contents or coprolites

which types of dinosaurs used herding?

Ceratopsians, Sauropods, Hadrosaurs, Ornithomimids

what evidence of herding is there?

1.) parallel trackways on the same plane of rock 2.) Large mass-death bonebeds of the same species

what evidence of migration is there?

1.) same species found over large areas 2.) tooth chemistry records change in drinking water source through life 3.) can determine type of dinosaur and its speed from trackways

what evidence of parental care is there?

1.) Brooding Parents 2.) Hatchlings without teeth 3.) close association of adult skeletons with young hatchlings

how can they use to approximate age?

bone microstructure, generate growth curves

what is the only way to distinguish between male/female

Can only tell if "its a girl, and she’s pregnant" - medullary bone =

what is medullary bone?

erratic layer of bone tissue inside mother’s limb bones formed by buildup of calcium reserves (to form eggshells and bones of the embryo(s)) — this means female and pregnant

what is a reason to think dinosaurs are warm blooded?

1.) dinosaurs walked upright —> most upright walkers today are warm blooded 2.) sauropods would need a strong heart to pump blood up to head —> warm blooded hearts are more efficient 3.) deinonychosaurians were clearly active predators —> active animals today are usually warm blooded 4.) Some dinosaurs lived in cold regions —> need to be warm blooded to live there 5.) Modern birds are warm blooded, so warm bloodedness had to arise at some point in the theropod lineage 6.) Dinosaurs grew fast —> similar to mammals which are warm blooded

what are the two paleontologists that changed the worlds perception?

Jack Horner and Robert Bakker

what did Robert Bakker do?

- 1960’s to 1970’s proposed dinosaurs were warm blooded - "dinosuars were active, fast, and agile"

what did Jack Horner do?

- 1979 discovery of Maiasaura (hadrosaurine) nests with hatchlings teens, and adults - "Dinosaurs were social animals and good parents"

what has been recovered from dinosaur fossils so far

1.) lipids (fats) 2.) carbohydrates 3.) proteins (no DNA yet)

what is applying biology techniques to the study of original molecules preserved in fossils

Molecular Paleontology