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50 Cards in this Set

  • Front
  • Back
Red Queen model
evolution driven by biotic factors - species diversity depends on things like body size, adaptation to hard times
Court Jester model
evolution driven by abiotic factors - species diversity depends on climate change, food supply
Alfred Wegener
Continental drift! Argued that sea floor spreading, mid ocean ridges, and supercontinents happen
Period + time?
Period + time?
Late Permian (~260 Ma)
Period + time?
Period + time?
Late Jurassic (152 Ma)
The supercontinent of Pangea began to break apart in the Middle Jurassic. In the Late Jurassic the Central Atlantic Ocean was a narrow ocean separating Africa from eastern North America. Eastern Gondwana had begun to separate form Western Gondwana.
Period + time?
Period + time?
Cretaceous (94 Ma) During the Cretaceous the South Atlantic Ocean opened. India separated from Madagascar and raced northward on a collision course with Eurasia. Notice that North America was connected to Europe, and that Australia was still joined to Antarctica.
Period + time?
Period + time?
Neogene (specifically Miocene, 14 Ma)
20 million years ago, Antarctica was covered by ice and the northern continents were cooling rapidly. The world has taken on a "modern" look, but notice that Florida and parts of Asia were flooded by the sea.
period + time?
period + time?
Early Jurassic (195 Ma)
South-central Asia had assembled,. Tethys ocean separated the northern continents from Gondwana. Pangea intact.
How do you measure life?
Find a lot of specimens and count up the species
quantifying first and last occurrences: sample a lot and project forwards and backwards.
Confidence interval: confidence interval as a fraction of stratigraphic range - look in ppttttt
When have you measured enough life?
Accumulation curves and rarefaction curves are good for looking at this.
Plots total of new species found against the total number of specimens collected or observed. S shaped curve - reaches asymptote where you're finding very few new species with more sampling.
rarefaction= = means of repeated re-sampling of all pooled individuals or all pooled sample = statistical expections for corresponding accumulation curves. taxa on y axis, specimens on x-axis
Problems at extinction boundaries with measuring species
Signor-Lipps effect: 1. With bigger/rarer things – it looks like you’re losing them along the way as you get to the boundary, but really you just don’t have enough specimens. Just cause you don’t find it up to the boundary doesn’t mean it went extinct before the boundary.
ii. Also drops familial diversity used to calculate drops in species diversity in mass extinctions underestimates overall decrease in species diversity
iii. Bioturbation
1. Reworking of soils – makes it harder to use stratigraphy to tell when something’s from
2. Sediment mixing
(important for boundaries b/c use stratigraphy to tell when boundary is)
Is it all just counting taxa?
1. richness v diversity:
richness = total number of species
diversity = total number of species combined with relative abundance of those species
2. functional ecology: what's happening in the ecosystem, roles species have in the ecosystem, how ecosystems were structured
3. morphospace occupation - morphological diversification, maybe what had what new morphological characteristics when
4. extinction and convergence
What are the biases?
Rock record (preservation bias, how much rocks you have from the time)
pull of the recent - a. Recent biota are better sampled – artificially inflate the diversity in younger time periods. But accounts for like only 5% of Cenozoic increase in bivalve diversity.
d. Nonlinear relationship between # of families and # of species → drop in family diversity at mass extinctions tends to underestimate the overall declines in species diversity
e. Ratio of species to families increases over geologic time – increases in familial diversity underestimate the increase in species diversity
1) What was Gerry Vermeij’s observation? What did he then hypothesize?
a. Vermeij’s observation in 1977 was that less sturdy shells, with open coiling, planispiral coiling, and umbilici, were more common in Paleozoic and Early Mesozoic gastropods, and strong external sculpture, narrow apertures, and apertural dentition were more common among younger (post-Jurassic) gastropods. He also observed that gastropod predator diversity radiated during the same time. Vermeij hypothesized that this was the result of top-down forcing during the Mesozoic – changes in the predators of gastropods caused changes in the gastropods – e.g. “evolution of powerful, relatively small, shell-destroying predators such as teleosts, stomatopods, and decapod crustaceans.”. Together with more grazing, this brought about huge changes in Late Mesozoic benthic populations, termed the Mesozoic Marine Revolution. MMR mostly happened (most evolutionary innovation) during late Cretaceous
What is the evidence for and (sometimes) against this idea from bivalves,
gastropods, crabs, fish, crinoids, urchins, and skates and rays?
The late Mesozoic = Triassic+Jurassic+Cretaceous
Decapods – more durophagy during late Mesozoic, also more nrg use, narrower apertures, fewer umbilici
Crinoids = more motile genera, more bite marks
Fish – not so much, no real trends for duraphagy for fish during Mesozoic?? There’s a genera richness spike of osteichthyans
Skates and rays – diversified
Arms race hypothesis
2) How would you describe the various patterns in terms of the ideas of Red Queen vs. Court Jester?
a. The patterns generally fit into the Red Queen model – at least Vermeij’s view of top-down forcing is a variety of the Red Queen model. ABIOTIC FORCING?????
What is the major change in the carbon cycle in the Mesozoic? Which two organisms drove it? Why does it matter for things like
i) the resilience of ocean environments to sudden greenhouse gas release?
The major change in the carbon cycle in the Mesozoic was that the ocean became carpeted in carbonate. Open ocean carbonate producers appeared during Mesozoic →
1) Major divisions of land plants (slide 6) and when angiosperms rose to dominance (slide 7)
Land plants are divided up into bryophytes, pteridophytes, gymnosperms, and angiosperms. Within land plants there are vascular plants, which includes the pteridophytes, the gymnosperms and the angiosperms. Within the vascular plants there are seed plants, which includes gymnosperms and angiosperms. Cladogram:
b. Angiosperms developed and rose to dominance during the Cretaceous: big spike in angiosperms during Albian during Cretaceous.
a. What makes angiosperms distinct? 5-key traits discussed in class. Need not know all the details, but basic ideas. Also be able to link the vegetative traits to water flow/use, and the reproductive traits to the relative timing of investment in nutritive tissues for seeds.
(more explanation in study guide)
1. reticulate venation
2. xylem with vessels
3. flowers with carpels and stamen
4. double reproduction/endosperm
5. very reduced male and female gametophytes
b. How did they evolve? What evidence lead to the Gnetifer hypothesis replacing the Anthophyte hypothesis for relationships among extant seed plants? What is ancestral state reconstruction and how is it being used to make a hypothesis of the first angiosperm flowers? What is one hypothesis for environment of early angiosperms and how does this effect their preservation potential?
a. numerous characters seemed to show that anthophytes close to angios – share micropylar tube and a lot of other traits
i. BUT w/ DNA sequencing found that anthophytes weren’t like angiosperms at all, even though had similar traits
so anthophyte hypothesis no good, even though supported morphologically. gnetifer (acrogymnospermae) hypothesis arose from dna sequencing
1. Basically just puts angiosperms all by themselves
2. Found caytonia (seed fern) most closely related to angiosperms
3. Found fossils of caytonia reproductive structure in Yorkshire
b. Vascular plants → angiosperms
c. Environment – dark and disturbed
i. Disturbed environment not so hot for plant preservation
How did they relate to Mesozoic global change? Be able to discuss the basic idea of Boyce & Lee and how this ties in to the previous lecture on changes in ocean ecosystems.
angiosperms have larger transpiration capacities (they can cycle more water cause more leaves and the xylem) and recycling of transpiration feeds rainfall, esp in the tropics
f. More rain = more rock chemical weathering → so if angiosperm-dominated ecosystem have more chemical weathering, so NUTRIENT LOAD of terrestrial runoff may have increased, even if runoff VOLUME remained constant, and remember increased nutrient load in terrestrial runoff is important cause it makes things easier for marine stuff- they can be more productive cause more nutrients
What are birds?
Avian synapomorphies: feathers (global), endothermy (local), enlarged brains (local), flight (local), reduced manual digits (local), no teeth (local), – global means only arose once in history of life, and local means arose separately. Local means other things can share it, a. Reptilian origin
b. Saurischians → so saurischians have a non-inverted hip, BUT then it inverted again w/ birds, so have inverted hips like ornithiscians and some saurischians – convergent evolution
c. Vertebral pneumaticity (air pockets in vertebrae → also saurischian trait)
d. Promaxillary fenestra
e. Furcula (wishbone) – basal most therapod feature
f. Def related to theropods
g. Most closely related to crocodiles
What are feathers
a. Sinosauropteryx (Theropod saurischian) had feathers
b. So feathers evolved with theropods (which are saurischians) –theropods evolved around 230 Ma (during Late Triassic)
c. T-rex had feathers, as did Beipiaosaurus
How did powered flight evolve
a. Modern birds have enlarged sternum for powered flight
b. Relationship between shoulder joint and body mass allowed them to separate flying birds from flightless birds – need sufficiently large shoulder joint COME BACK TO THIS
c. Confusciornis and archaeopteryx probably incapable of powered flight
d. First flyer was iberomesornis romerali (enantiornithes – part of ornithoraces)
Archaeopteryx is a key fossil for birds: what are the characters that make Archaeopteryx a transitional fossil?
a. Didn’t fly BUT DID have:
1. Retroversion of the pubis
2. Reduction of long bony tail (evolution of pygostyle – fused final vertebrae)
3. Loss of teeth
4. Acquisition of sternal keel (important for flight)
b. Did Archaeopteryx have powered flight? What is the evidence?
a. Probs Nah. Had feathers and wings, but for one thing body mass was too high compared to coracoid HAF length
b. For another thing wings had multiple layers of feathers – limits flight ability
c. multi-layered wing lacks a distally slotted configuration, a feature that reduces induced drag during flight [15]and is particularly important at slow speeds
3) What happened at the K-Pg boundary and how do we know? (RE BIRDS)
a. Major mass extinction of Archaic birds at K-Pg (Cretaceous Paleogene)
4) unclear whether archaic birds became extinct gradually over the course of the Cretaceous or whether they remained diverse up to the end of the Cretaceous and perished in the K-Pg mass extinction. (Signor-Lipps effect!)
disappearance of fossil evidence of birds except Neorthines. None of these groups are known to survive into the Paleogene, and their persistence into the latest Maastrichtian therefore provides strong evidence for a mass extinction of archaic birds coinciding with the Chicxulub asteroid impact. Most of the birds described here represent advanced ornithurines, showing that a major radiation of Ornithurae preceded the end of the Cretaceous, but none can be definitively referred to the Neornithes. Neornithes made it through Cretaceous → Enantiornithes, Apsaravis clade, Hesperonithes, Ichthyornithes, laceornis clade didn’t make it through K-Pg boundary – asteroid??
. What happened at the K-Pg boundary?
K-T boundary – Cretaceous-Tertiary. Mass extinction. 66 Ma. Lost a lot of megafauna on land and sea, as well as key groups like pterosaur, rudist bivalve, belemnites, ammonites, planktonic forams.. About 75% species loss on average, generally greater loss in pelagic, selective extinction. KT boundary in Italy shows abrupt loss of fossils
2) What killed the dinosaurs and how do we know?
i. Asteroid impact
ii. How do we know?
1. There’s a crater! Chicxulub Crater in Yucatan peninsula
2. Too much iridium (from space!)
3. Slumping along N. Am margin
4. Tsunami deposits
3) What was the Alvarez hypothesis?
a. That there was an extraterrestrial event at the K-Pg boundary causing a mass extinction (first off just planktonic forams, then later dinos and everything)
a. What evidence did they give?
a. 30x too much iridium in K-Pg boundary line – global phenomenon
b. wasn’t supernova because there wasn’t the plutonium 244 spike that should accompany a supernova
c. so concluded it had to be an asteroid
b. What lead them to ask the question in the first place? And how does this tie into the ideas of Uniformitarianism versus Catasotrophism?
a. They were looking at the Scaglia Rosa to do some stratigraphy/tectonics research
b. Scaglia Rosa is a sedimentary rock, made of fossils → lots of planktonic forams. And noticed major extinction in planktonic forams at K-Pg boundary. So fast! To make sure it wasn’t an unconformity, or a very small amount of deposition in a long time or something, decided to use iridium dating! But the iridium dating showed wayyy too much iridium. Paleomag data indicated it was a short boundary.
c. Catastrophism is old view of Earth’s geology – that stuff happened in fast, cataclysmic events.
d. Uniformitarianism says geologic events are slow and gradual and constantly happening. Uniformitarianism is mostly right, but of course there ARE catastrophic events
4) There are women in this story! What did Helen Michel do? What about Isabella Premoli-Silva?
a. Helen Michel was on the research team with Walter and Luis Alvarez, and Frank Asaro – did a lot of the key measurements, like ruling out the plutonium hypothesis.
b. Isabella Premoli-Silva – identified forams – showed extinction
5) Besides iridium, what lines of evidence support the impact of a very large asteroid at the K-Pg boundary?
a. Shocked quartz – highly, rapidly metamorphosed from high pressure, low T → structure deformed
b. Microtektites – glassy particles formed from molten rock ejecta
c. Tsunami deposits
d. Deformation along N. Am margin – slumping where expected
e. Distribution of ejecta – more ejecta near crater
6) What are the immediate and long term kill mechanism from the impact?
a. Immediate
i. Massive earthquakes
ii. Tsunamis
iii. Ejecta
iv. Wildfires
v. Acid rain
vi. Darkness

b. More long term:
i. Productivity loss from darkness
ii. Acidification
a. Know the Strangelove ocean hypothesis & how this ties to the carbon pump
a. Minimal export production cause collapse of food chain after K/Pg mass extinction
b. Ocean became more anoxic and sulfidic → extinction → collapse of food chain
Shuts down carbon pump -biological pump, in its simplest form, is the ocean’s biologically driven sequestration of carbon from the atmosphere to the deep sea.[
c.
d. Surface to deep carbon 13 gradient collapses
1. “Strangelove ocean” – collapse of bottom of food chain
2. CaCO3 of shell reflects the water they leave in – isotopic composition different in shallow ocean and deep ocean
3. Algae preferentially take up C12, and when they die they take it to the deep ocean
4. Surface ocean forams has relatively heavy carbon CaCo3 (C13), and benthic forams have relatively light CaCO3
5. At K-Pg boundary, have forams with same carbon composition
6. This could have also been produced by same amount of life but it doesn’t export the carbon
7.
e.
what is the evidence for acidification?
you need to answer this
1) What are mammals? Know synapomorphies
a. Fur/hair
b. Endothermy
c. Mammary glands
d. (1 fenestra per side)
e. (live young)
f. muscular diaphragm
g. single bone in lower jaw, remaining three jaw bones for middle ear bones
h. epiphyses on long bones and girdles
i. erythrocytes lack nuclei at maturity
j. complex dentition
k. double occipital condyle
2) What are the modern lineages, their general characteristics, and diversity?
Monotremata vs. Theria (Marsupials vs Placentals)
There are monotremata and therans, and within therians there are marsupialia and placentalia
Monotremata:
• Milk fields
• Lay eggs
• Cloaca (one opening for reproduction, urination, and excretion)
• Reduced teeth (derived)
• Electroreceptors in snout (derived)
• Low body temp (90˚ F)
echidnas and platypus

Theria:
• Nipples
• Penis in males, vagina in females
• Reduced eggshell and egg to amniotic sac
• Eggs hatch in uterus
• Tribosphenic molars
Marsupials
• Pouched
• Males have 2 pronged penis and females have 2 pronged vagina
• Have tiny young that are nourished in pouch, relatively low body temp
• Kangaroo, opossum (not Australian, but most of em are)
Placentals
• Separate opening for reproduction, urination and excretion
• Young nourished by placenta
• Long gestation, large young
• High metabolic rate
most diversity
3) Mammal ancestry – synapsid lineages from Carboniferous to present
a. Carboniferous – start of synapsids
b. Permo-Triassic radiation of synapsids (one hole) (down with therapsids – more radiation)
c. Triassic radiation of cynodonts and mammaliaforms
d. Jurassic-Cretaceous radiation of true mammals
e. Rise of mammals after dinosaur extinction
Soooo – synapsids → therapsids → theriodonts → cynodonts -→ mammals
a. Who is Morganucodon, when did it live,& why do we care?
a. 6 inch long insectivorous cynodont, late Triassic, major shift in evolution → well-preserved, shows completion of dentary-squamosal jaw joint, and differentiation in dentition (cheek teeth divided into premolar and molars)
4) Who is Juramaia and what age is it? Why is this fossil important for understanding mammalian evolution?
a. Earliest placental – small, insectivorous, middle Jurassic. Climbing specializations, so maybe Therians evolved in trees
5) Multituberculates are important, diverse, Cretaceous & Paleocene lineage of mammals. What are they defined by? And how do they related to modern mammals?
a. Thrive after K-Pg
b. Longest of any mammal lineage
c. They are defined by their teeth – which have a lot of cusps – tubercles in a row – different from tribosphenic molars
6) What was the hypothesis for the radiation in mammal body size and dominance in the Cenozoic? (hint: had to do w/dinosaurs)
a. Dinosaurs went extinct, mammals came in and filled the niche
Icehouse-Greenhouse Climates (22)

1) What are they? And which one dominates in earth history?
a. Greenhouse dominates, and refers to a climate too warm to sustain substantial continental glaciation. Icehouse climate refers to Earth w/ substantial glaciation (like Antarctica). Our icehouse climate has lasted since the Oligocene (no more than 35 Ma), previous Ice-House climates were Carboniferous-Permian, Late Ordovician, and Neo-Proterozoic
2) What is the evidence for large-scale climate change in the past?
a. Coals – show wet warm/wcool environment
b. Ice deposits – cold environment!
c. Evidence of glaciers – erratics, striations, till
d. Fossils – generally warm to termperate environement
e. Evaporates – warm and dry
f. Specific clays – warm and wet
3) What factors control earth’s climate history?
a. Solar radiation (increasing over time)
b. Atmospheric condition (greenhouse gases – carbon dioxide, water vapor, methane)
i. Carbon cycle: atmospheric CO2 controlled by:
1. Sea floor spreading and volcanic outgassing
2. Mountain building
3. Silicate chemical weathering

4. Evolution of plants etc

c) boundary conditions, like the gulf stream I guess??
4) Know key characteristics of the most recent icehouse/greenhouse climates (Mesozoic-Cenozoic). When did the earth switch from a greenhouse to an icehouse?
a. High concentrations of CO2, H2O, CH4
b. Higher sea level
i. Volume of ocean basin decreased – rifting creates young ocean crust, less dense, floats higher on asthenosphere
ii. Water less dense → rifting increased subduction, CO2 emissions → higher global temperatures, water volume greater with higher temp
c. Enhanced hydrologic cycle
d. Reduced meridional temp gradient
e. Expanded tropical belt
f. Eocene – palms at North Pole, and alligators. Arctic lake!
g. PETM
widening of oceanic passages --> thermal isolation of Antarctica
5) What are the abrupt events that characterized the most recent greenhouse?
PETM, hyperthermals, ocean anoxia (READ PAPER. THAT IMPORTANT PAPER.) THE PAPER WILL TELL ALL FOR THIS SECTION I THINK .
orbital processes and climate:
precession, obliquity, eccentricity
precession: earth's wobble of axis of rotation - climate change effect highest at equator
obliquity: earth's tilt, exaggerates seasons when greater, higher at lower latitudes?
eccentricity - shape of earth's orbit, not really that big of a deal on its own