Exam IV Flashcards
Why did it take so long for oceans to recover after the Permian extinction?
severe anoxia (low oxygen levels) in water, made it hard for life to recover, especially benthic organisms
What rock do coccolith plankton form?
chalk
Mollusks common in the Western Interior Sea? (Cretaceous)
bivalves (oysters, clams, rudists) ammonites (distinct suture patterns), belemnites (cigar bitches)
Which type of coral dominated Mesozoic and Cenozoic oceans?
scleractinian
What are the reptile groups of Mesozoic life?
archosaurs (basal and flying): includes dinos, pterosaurs, crococdilians, and birds
pterosaurs (aerial reptiles),
early birds: evolved from basal archosaurs (theropod dinos)
What is a dinosaur vs. not a dinosaur?
dinos have upright stance
marine reptile, crocodiles, and and flying archosaurs (pterosaurs) don’t have this stance
Know the difference between the predatory marine reptiles: plesiosaurs, mosasaurs, ichthyosaurs
plesiosaurs: paddle swimmer boi
mosasaurs: evil whale
Ichthyosaurs: evil dolphin
Mammals: tooth structure tells them apart. How do Mesozoic mammals differ from Cenozoic ones?
Cenozoic mammals fill in niches of dinos and greatly evolved (enter placentals)
triconodons: a mesozoic early form of mammals
gymnosperms vs. angiosperms
gymno: non flowering seed plants
angio: flowering seed plants
How do angiosperms coevolve with insects/animals?
spread pollen by attracting insects and herbivores with flowers and fruit
What caused the end Triassic extinction, and who suffered/benefitted?
cause: large volcanic eruptions related to rifting of pangea
suffered: marine life, therapsids (reptiles with mammalian traits), large amphibians, most archosaurs
benefitted: basal archosaurs/aka dinos
In which period did dinosaurs evolve?
Triassic
Given a picture and name of dinosaur, identify them as lizard-hipped (Saurischians) or bird-hipped (Ornithischians).
Saurischians: brachiosaurus, T Rex, velociraptor
ornithischians: hadrosaurs (duck billed), triceratops, stegosaurs, ankylosaurs
Gimme the deets on the dinos
Saurischians
1) Sauropods (apatosaurus, brachiosaurus) 2) theropods (t rex, velociraptor, hollow bones gang)
Ornithischians
1) thyreophora (stegosaurs, ankylosaurs) 2) ornithopods, bird feet gange (hadrosaurs) 3) triceratops
What is the evidence for cold or warm-bloodedness and links dinosaurs to birds?
evidence for warm blood: bone microstructure, fast growth rate, complex chewing/slicing teeth (warm blood predators would need teeth like this to eat a lot of food to fuel themselves), feathers found on small theropods that insulated them (warm blooded trait, bird link)
Which group did birds evolve from?
What’s their key ancestor?
Saurischians-theropods
theropod ancestor: achaeopteryx
What played a role in global dinosaur dispersal and diversity?
the continued rifting of pangea into geographically isolated continents
What are the three hypotheses for the Cretaceous extinction event, and the evidence?
1) sea level regression, changed climate and ecosystem
2) increased volcanism, deccan traps
3) meteorite impact
When did the Mesozoic end and the Cenozoic begin?
66/65 ma
What caused the Himalayan Orogeny, Alpine Orogeny, and Andean Orogeny?
Himalayan: continental collision of India and Asia
Alpine: microplates slam into south europe
andean: subducting plates ocean-continent
What is the tectonic setting of the Circum-Pacific Orogenic Belt?
subduction zones, volcanoes, earthquakes
What is the evidence that the Mediterranean Sea dried up?
different marine organisms found before and after dry spell
sediment fill gorges originally made by rivers that cut down to base of sea bed
Laramide Orogeny’s intermontane basins record what ancient climate?
shows history of lakes, swamps, and coal formation…warm, wet climate
What caused the Paleocene-Eocene Thermal Maximum?
large release of undersea methane bc of rifting
What caused the Earth to cool in the Eocene?
breakup of Antarctica from Australia, forming antarctic circumpolar current
How did the South Dakota Badlands form? What climate transition is recorded there, and what caused it?
uplifted with laramide orogeny, accumulated from mountain erosion
warm subtropic forest, savanna, semi-arid
bc of uplift of black hills and formation of rain shadow
Know how these Western North America features formed: Colorado Plateau, Yellowstone hotspot, Cascade volcanoes, Basin and Range extension, San Andreas fault
C. Plateau: uploaded as single block with volcanic margins, stimulated erosion of C river and Grand C
Y Hotspot: mantle plume ig
cascade volcanoes: subduction of juan de fuca plate
basin and range: relaxing of crust following laramide uplift
San Andreas: complete subduction of Farallon plate, transforming west coast from convergent to transform
What organisms rebound in the oceans following the Cretaceous extinction?
mollusks and fish
What is the dominant marine predator in the Cenozoic?
sharks (chondrichthyes)
What are the significance of Angiosperms and grasslands in the cenozoic?
both expand and replace forests bc of cool, dry climate
co-evolve with insects and plant eaters (teeth evolution)
Why did birds become so diverse in the cenozoic?
adaptive radiation in response to varied habitats
Mammals: What are the key features of marsupials and placentals?
marsupials: young develop in pouch
placentals: young stay in womb until birth, fed by placenta
What are the differences and significance of the placental groups (edentates, rodents, carnivores, ungulates)?
edentates: toothless, armadillos, tree sloths, anteaters
rodents: gnawers and nibblers
carnivores: meat eaters
ungulates: hoofed mammals + whales and elephants
What are the trends in horse evolution?
horses went from 3-5 toes and low-crowned teeth to one toe with high crowned teeth, went from big to small
How did whales evolve?
used to have legs and come on land
transition from fish to plankton eating
vestigal hind legs and pelvis
What types of fossils are preserved in the Badlands, and why are there so many?
vertebrate fossils
flash flooding burial
What is an example of convergent evolution in mammals?
marsupial saber tooth vs placental saber tooth
(think shark and dolphin looking similar even tho they’re not related)
convergent: different ancestry, similar purpose
divergent: similar ancestry, different purpose
What happened to mammals in the western hemisphere when the Isthmus of Panama formed?
marsupials spread north
placentals spread south
What is the importance of the formation of the Isthmus of Panama in the ice ages?
blocked atlantic-pacific water interchange
formed gulf stream, directed northward which brought more warm water and humid air north, resulting in increased snow precipitation
Compare the terrestrial vs. marine (deep sea) record of the ice ages – which one is better?;
terrestrial: lack fossils, glacial erosion, porrly sorted till
marine: continuous sedimentation, fossils, oxygen isotopes
what is difference between O-16 and O-18 and what do they mean regarding Earth’s temperature?
O-16 trapped in glacier ice during cold times
more O-18 in ocean during glacial times
Milankovich cycles – What is the difference between Earth’s wobble (precession), eccentricity of orbit, and axial tilt?
precession: wobble of axis, changes timing of seasons
eccentricity of orbit: elliptical vs circular, affects amount of solar radiation
axial tilt: obvious, affects length of seasons
What features are the result of the ice age
glacial moraines, sea level change, crust depression and rebound, river redirection, kettle lakes, glacial retreat lakes, pluvial lakes,
Why did catastrophic floods happen in Washington state at the end of the ice age?
ice dams blocked rivers and formed lakes, but when ice melted, dam destabilized and floods happened
What part of South Dakota was influenced by glaciers?
east river
What are some examples of Pleistocene megafauna, including the mammoths?
beavers, mammoths, mastodons, sloths
What caused the Pleistocene extinctions, and who suffered?
hunting, climate and vegetation change
megafauna suffered most (overhunted and couldn’t reproduce fast enough)
What was the climate of the Holocene like until recently?
warm, stable
How have changes in climate impacted people?
fertile crescent, medieval warm period, little ice age
What has caused climate change to occur on Earth naturally over time?
plate tectonics, milankovitch cycles, changes in greenhouse effect, solar variability (sun spots), volcanic eruptions
What are the roles of plate tectonics, Milankovitch cycles, the Greenhouse Effect, the Sun, and volcanic eruptions? Over what time scales do these act to alter the climate?
plate tectonics: millions of years milankovitch cycles: tens of thousands greenhouse: thousands of years solar variability: 11 year cycles eruptions: who tf knows
what are greenhouse gases, and how does the carbon cycle work?
gases that absorb and emit infrared energy, causing warming (CO2, methane, water vapor)
carbon cycle: carbon transfer between atmosphere, ocean, rock, biosphere
What is causing climate change to occur now? Why isn’t the sun or volcanic eruptions responsible?
humans: fossil fuel burning, bogs, farm animals, rice, burning grasslands, combustion
What is the evidence that Humans are causing climate change now?
human added CO2 has no C-14 (it’s how we track what we contribute)
What will happen if warming continues?
melting glaciers and permafrost
rising seas
altering weather patterns
habitat impacts
What is the difference between weather and climate?
weather: current changes
climate: long term averages
What is the Anthropocene Epoch?
A new proposed epoch characterized by overwhelming human influence eon earth’s systems (most support it for starting with the Atomic Age)
