What are the integers

April 5, 2015  Biogeography  study of the spatial distribution of organisms o Where are they o Why do we find animals and plants where they are  Paleobiogeography  spatial distribution of organisms through time  Cosmopolitan  organism has a widespread distribution o Found in a lot of places  Endemic  something has a localized distribution o Only find them in one place  How do organisms get where they are o Evolve in place  Your ancestors were there, so now you are there o Disperses there / migration  Moves there from somewhere else  Range extension  if an organism has a small or endemic range and extends that range  Environmental tracking  a lot of organisms have evolved to live in certain conditions  When conditions change, they are going to move with that condition  Sweepstakes dispersal  rare  Dispersal across a major geographic boundary o Vicariance  Separation or division of a group of organisms by the erection of a geographic boundary  Can be very large scale, can be very small scale  How did isolation of the continents effect life o Endemism  Late Triassic through Middle Jurassic  Disparate dinosaur faunas still show great similarity in taxa and faunal composition  Ocean circulation pattern o Major driver of climate o Water stores heat extremely well  Top few meters of sea water store as much heat energy as the entire atmosphere o The ocean surface stabilizes the atmospheric flow patterns  depend on heat supply o General circulation of the atmosphere is closely related to the circulation of the ocean April 7, 2016  Cenozoic o Still quite warm o Low pole-to-pole gradients o No ice at the poles  Early part of the Cenozoic  Right at the Paleocene-Eocene boundary o Warming trend  PE Thermal Maximum (PETM)  First recognized in 1990 o 56 million years ago o Lasted for 200,000 years o Temperatures increased from about 6 to 9 degrees Centigrade globally o Average global temperature is around 73 degrees Fahrenheit/ 23 degrees C o We know this from ocean cores  forams  Forams  live in the ocean, build a shell out of calcium carbonate  We can look at the shells and test the oxygen composition over time 16 18  O to O o Deep water was around 60 degrees Fahrenheit  Natural Carbon cycle on Earth o Lots of CO2 is produced and then absorbed in carbon sinks 13 12 o Huge amounts of carbon  C depleted / more C o Entering the atmosphere and entering the carbon cycle  This is what is causing the warming of the Earth  Volcanism o Centered around Greenland/Baffin Island o Opening of the North Atlantic  Rifting and volcanism going on in this part of the world o Looks at the igneous basalts  You can estimate what kinds of gases are coming out of this material  Estimated that there is 1C depleted CO2 and CH4 gases produced by volcanism o Basalts were placed out onto the sea floor  Sea floor is full of carbon rich sediment  Start warming up the atmosphere by all the greenhouse gases coming up o A lot of the CO2 in the atmosphere gets absorbed into the ocean  Trying to balance out the carbon o Result of this is that the ocean warms o If you warm the ocean up enough, you start melting methane hydrate/clathrate o Methane hydrate  Methane molecule that is enclosed in ice  Trapped on the sea floor o When the methane hydrate melts, you increase the amount of greenhouse gases  Add enough CO2 and methane into the atmosphere, the ocean absorbs more of the CO2 o Acidifies the ocean o 50% extinction of benthic forams during this PETM  Benthic  the ones that live on the bottom  CCD carbonate compensation depth o Below this, the pressure is so high that calcium carbonate will dissolve o If you have sediment below 4 km, you don’t get any fossils because all of the shelves dissolved o During PETM, the CCD rose to about 2 kilometers  A lot more of the ocean floor with no fossils in it  Because of the acidification of the ocean, more calcium carbonate shells dissolved o In a lot of places, you find red clay in the PETM area if you took a core of the sea floor o If there is a lot of CO2 in the ocean, its harder to deposit any limestone  Boundaries are named because of the big events that happened  When you look at the PE boundary, you see a huge diversification of mammals o We see the first real flourishing of primates during the PETM o Some sort of correlation between the PETM and the evolution of mammals  Multituberculates existed for 100 million years  Monotremes  alive today: platypuses and echidnas o Live only in Australia and New Guinea today  Marsupials o Southern hemisphere success story  Placentals  4000 known species alive today o Dominate everywhere except Australia