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Who was Andrew Carnegie and what did he do for science?
He was a major industrialist of his time, and one of the wealthiest men in the world. He gave much of his fortune away to develop centers for science and the arts, including the Carnegie Institution of Washington.
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Where is Tumamoc Hill and what types of studies are done there at the Desert Laboratory?
Tumamoc Hill is in Tucson. Long-term ecological projects on desert plant ecology, archeological and plant-climate work is done at the Desert Laboratory.
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What are packrat middens and why are they important to understanding the vegetational history of Arizona
and the Southwest in general?
They are assemblages of plant remains: twigs,leaves, etc. that were collected by the pack rat Tecoma, and used in nest building. The pack rats urinate on the middens, which preserves them in the desert. They demonstrate that the modern zonation in Arizona today was not as strict as it was in the past, and that plants of cooler clines today had more southerly distribution.
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Why did Paul Martin, who was used to studying Pleistocene pollen cores, start studying packrat middens when he came to Arizona?
The packrat middens contained pollen profiles, since AZ didn't have a lake he could core for pollen.
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When did radiocarbon dating develop and why is it valuable for packrat midden studies?
- It allowed for an independent dating of sediments that in turn helped pinpoint the ages of archeological
- digs, packrat midden sites etc. in order to understand more of the environmental and human prehistory of the Pleistocene and Quaternary of the Southwest. Developed in the late 1940s
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Merriam’s Life Zones and modern vegetation zones in the West are based on what factors?
elevation and precipitation are important factors in western vegetation
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How did the vegetation change in SW Arizona throughout the Pleistocene, and how different it is there today than at previous times in the Pleistocene?
during the Pleistocene, there were more conifer forests, alpine and subalpine woodlands, and they reached much further south than today. Deserts and grasslands expanded.
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What is the Overkill Hypothesis and what is the evidence for it?
- the arrival of humans in the new world coincided with Pleistocene megafauna
- ...extinctions run from N to S
- ...climatic change too gradual and at the wrong time
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Where and what is Head-Smashed-in-Buffalo-Jump?
It is in Alberta, Canada
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What did the isthmus of Panama change with regard to North and South American mammals? in regard to the climate in Florida, Alabama, and Mississippi? How were these changes observed in the pollen and marine record of western Florida? (see Willard paper) How about the differences in plants of the Citronelle Formation in relation to what grows there today?
the isthmus allowed mammals to migrate into north and south america. The isthmus caused the climate in FL AL and MI to become much warmer due to ocean currents. White pines (citronelle formation) were there and are no longer present today.
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What are softwoods and hardwoods, which plants produce them and how do they differ?
- soft woods have very uniform wood. (gymnosperms: conifers)
- hard woods have large vessels and lots of fibers (woody dicots)
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In the Northwest, how did the vegetation change from the time of the Deschutes flora to the Tulelake flora to the modern Palouse Prairie flora?
started as deciduous hardwoods and shrublands, went to mixed conifers, and today we have grasslands
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How did the flora in the Bering Strait change during the Pleistocene?
it becomes much more diverse in the Pleistocene?
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Grass morphology and growth
- Rhizome: horizontal stem of a plant found underground
- Stolon: horizontal connections between organisms found above ground
- Tiller: a stem produced at the base of grass plants; segmented, each producing its own two part leaf
- Crown: the totality of a plant's above-ground parts
- Blade: the plane of the leaf
- Intercalary meristems: allow for rapid regrowth; stem elongation
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What is C4 metabolism and what is its advantage for C4 plants growing in hot, dry places?
- CO2 is incorporated into organic acids (carbon fixation) in the mesophyll cells, and the organic acids release CO2 to the calvin cycle in the bundle sheath cells.
- Rubisco gets a steady supply of CO2 which allows for a high rate of photosynthesis in hot dry environments.
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Bundle sheath
in C4 plants, use carbon fixation to carry out photosynthesis when normal conditions arent present; photosynthetic; arranged around the veins of a leaf
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Mesophyll
Most of the interior of the leaf; primary location of photosynthesis
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Rubisco
an enzyme that catalyzes the first major step of carbon fixation
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Malic acid
a source of CO2 in the calvin cycle; important in causing stoma to open
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PEP carboxylase
metabolizes CO2 into a 4-carbon product in the mesophyll
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What are phytoliths and why study them in fossil grasslands? Why not just use pollen?
they are silicate bodies produced by grasses. they have a variety of shapes and are of taxonomic use. Pollen cant be used because it doesnt preserve that well and makes relatively small amounts of sporopollenin.
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When do grasses first appear as a group compared to when they become a major vegetation type?
Grasses first appear in the paleocene. they become a major vegetation type in the miocene and pliocene
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What is the difference between regular short (bunadont) teeth like we have and the high crown (hypsodont) teeth of horses? How do these teeth function for herbivores compared to how carnivore teeth work? How are these teeth an advantage to grassland animals?
High crowned teeth allow for more wear since there is more tooth exposed. Animals that feed on abraisive substances need higher crowns. these teeth are used for pulverizing and breaking food down. carnivorous teeth are for shredding, rather than breaking down. grassland animals need high crowns with flat tops to chew grass.
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How did locomotion and foot morphology change in horses from their ancestors in the mesic woodlands to animals that live in grasslands? What other changes occurred in ungulates such as cows?
Foot morphology progressively moved from 5 ties to fewer toes. This allows for faster turnover of the foot and thus faster running.
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When was the maximum extent of the deciduous forest in the Northern Hemisphere? What are some of the groups that were around then that still occur in the eastern deciduous forest?
The maximum extent of the deciduous forest was in the middle of the Miocene, 15mya. White oak still occurs today, sycamore, and sassafrass as well.
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How are the fossil leaves preserved at Clarkia, Idaho and what kinds of structural and biochemical information can be obtained from them?
Leaves were preserved in anoxic conditions in lake deposits. We can obtain chloroplasts, DNA, and even cuticles of these leaves.
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How did the permineralized fossil fruits and seeds and ferns form in the Yakima Canyon flora?
the same way as any other permineralization. supersaturated groundwater.
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What plants lived in this swamp that still live in swamps in the Southeast today?
the bald cypress, sweet gum, pine, royal fern, virgina chain fern
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What is homospory? How do ferns reproduce?
Ferns use spores to reproduce, and homospory means that they use the same size and type of spore to do so.
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Sporophyte
produces spores by meiosis
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Sporangium
the structure that produces and contains spores
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Sorus (plural: sori)
a cluster of sporangia
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Gametophyte
the multicellular phase or structure that contains a single set of chromosomes
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