week 12

Question 1

briefly describe the ordovician ME

Answer 1

One of the big five mass extinctions. Affected only marine organisms.

Question 2

briefly describe the devonian ME

Answer 2

One of the big five mass extinctions. Largely affected marine organisms, but also some early vertebrate clades.

Question 3

briefly describe the permian ME

Answer 3

Largest of the big five mass extinctions. Affected marine invertebrates, insects, synapsids and anapsids.

Question 4

looking at stratigraphy, what is our evidence of a meteorite impact for the cret ME

Answer 4

iridium (rare element not really found on earth)

tektites (superheated and cooled glass formed from heat of impact)

shocked quartz (form of quartz only found in extreme impacts, such as meteorites or atomic bombs)

Question 5

what do the deccan traps indicate?

Answer 5

large deposit of volcanic rock in india illustrating massive volcanic eruptions around the time of the end cret

Question 5

where did the end cret meteorite hit?

Answer 5

in the yucatan peninsula, creating the chicxulub impactor site. the crater ring had since collapsed and left us w cenotes sinkholes in a circular pattern marking the rim of the crater

Question 6

briefly describe the triassic ME

Answer 6

all archosaur that weren’t crocodylomorphs, pterosaurs, and dinos died.

lepidosaurs survived a bit but we aren’t really focused on them

synapsids were hit hard but most importantly, small mammals were still kickin

Question 7

who lived and died from the cret ME

Answer 7

all non avian dinos died, as well as the large marine diapsids (mosasaurs and plesiosaurs), the pterosaurs, and many ancestors of birds

survivors were mammals, turtles, crocs, amphibians, and fish

generally, those that died were large and survivors were small

Question 8

what three animals did we go over that got extinct by humans

Answer 8

thylacine aka tasmanian tiger, carolina parakeet, passenger pigeon

Question 9

there’s the hypoth that dinos went extinct bc mammals starting eating dino eggs. is this plausible or no?

Answer 9

not really plausible bc why did mammals all of a sudden start doing that. and also why did so many non dino organisms die at the same time (pterosaurs, mosasaurs, etc)

Question 10

theres a hypoth that the dinos went extinct bc of an ice age. is this plausible or no?

Answer 10

no bc its misguided

there was an ice age after the cretaceous, but this fall was gradual and didnt occur til millions of years after dinos were gone

Question 11

theres a hypoth that the dinos went extinct bc they made too much methane. is this plausible or no?

Answer 11

i mean.. possibly… but we can’t really test it and it relies on a lot of assumptions about dino physiology

Question 12

theres a hypoth that the dinos went extinct bc of a supernova. is this plausible or no?

Answer 12

no bc a supernova would scorch everything and nothing would survive

Question 13

theres a hypoth that the dinos went extinct bc of a viral outbreak. is this plausible or no?

Answer 13

not really bc viruses don’t affect diff species that commonly, let alone so many different organisms

Question 14

theres a hypoth that the dinos went extinct bc of volcanoes gassing the atmosphere. is this plausible or no?

Answer 14

okay now we’re getting somewhere

its plausible and we have evidence from the deccan traps dating to around the end of the cretaceous, but there’s just a stronger theory

Question 15

we think the dinos went extinct bc of a meteorite. when the meteorite hit, what would’ve happened?

Answer 15

initial impact would have caused huge tsunamis

ejecta would have been sent flying into the air, and friction from the air would have superheated it, cooking whatever it fell on

debris prob stayed in the air for a while, causing a mini winter and fucking up photosynthesis

Question 16

when the meteorite hit, why were the dinos unable to survive?

Answer 16

those that survived the initial impact would have been unable to find enough food to survive, whereas smaller animals could have found shelter underground or in the water and met their energy req by scavenging and eating leftover plant matter

Question 17

will we ever bring dinos back?

Answer 17

short answer no bc DNA is delicate and soft tissues and proteins aren’t enough

Question 18

name two dudes that survived the cret ME but didn’t make it to today

Answer 18

champsosaurs and multituberculates

Question 19

could we put dino DNA in a bird to wake up its latent dinosaur ancestor

Answer 19

i mean theoretically yeah, and we’re trying this on wooly mammoths rn, but so far dudes who go through this don’t survive more than a few days (we did this w a frog species and an ibex species already)