Part IV: Multiple Choice - 2 points each 1. The Mid-Atlantic Ridge is an example of A) Convergence B) Divergence C) Subduction D) Folding 2. Tectonic plate motion is driven by A) Conduction B) Convection C) Compression D) Magma plumes 3. The lowest layer of the atmosphere, the troposphere, extends to about 10 km (except at the poles). Half of the atmosphere's mass is above you if you are at about A) 4.0 km B) 5.5 km C) 7.0 km D) 8.5 km 4. Temperature is a measurement of A) Heat capacity B) Average heat capacity C) Kinetic energy D) Average kinetic energy 5. Chinook winds are always A) Warm B) Cold C) Long-lasting D) Fast 6. True alpine vegetation covers about how much of Earth's land? A) 1% B) 3% C) 10 % D) 14 % 7. Alpine plants exhibit seasonal phenology, which means that they exhibit temporal control of A) Seed maturation B) Sprouting C) Flowering D) All of the above 8. Most avalanche-related deaths are caused by A) Sluff avalanches B) Slush avalanches C) Slab avalanches D) Earthflows Part V: Short Answer – 5 points each 1. Give at least two reasons why the "local" perspective might be important for defining a mountain? There is no universal definition for a mountain, so the local impression may be the single defining factor. Peattie wrote that a mountain should “…enter into the imagination of the local people." What defines a mountain (in terms of height) might be relative to the local, surrounding landscape/topography. Mountains may be defined according to local traditions or to religious or cultural practices. 2. Marine fossils have been found on top of Mt. Everest. How might this be possible? As the Indo-Australian slammed into the Eurasian plate (two continental plates), great amounts of compression and folding occurred. The continental plates were originally located below sea-level, however the boundary between the two plates was compressed and thrust upward, eventually becoming part of the mountaintop. 3. Describe major differences between continental and oceanic plates. Continental plates are older, thicker, and less dense than oceanic plates. Continental plates are also made predominantly of silica and aluminum while oceanic plates are made predominantly of silica and magnesium. 4. Describe three different processes by which mountains can form and give examples of each. Possible processes include… Convergence - continent/continent – compression, folding Convergence - continent/oceanic (subduction okay too) Volcanic Activity Hotspots 5. How do oceanic and continental hotspots form? Give an example of each. Hotspots form when stationary magma plumes are hot enough to break through the crust. 6. Why does temperature generally decrease with elevation? Temperature decreases with elevation because pressure decreases. Air masses rising into areas of lower pressure expand, and in expanding they do work. By doing work, the air loses kinetic energy and cools down. 7. Why is there more precipitation at higher elevations? Because temperatures are cooler at higher elevations, an air mass will reach saturation more quickly (cold air holds less moisture than warm air). When the temperature cools to the dew point, water vapor in the air mass condenses and may eventually precipitate. 8. Imagine elevated ozone (smog) levels have been recorded in Colorado's high country and the Denver region is believed to be the source. Explain how this might be possible and say whether the ozone problem is diurnal, nocturnal, or continuous. A valley breeze forms when sun rises and begins to heat the Front Range’s mountain slopes. This differential heating causes the warmed air to rise upwards, creating an upslope circulation. This circulation carries pollution from the valley/plains up into mountains. The problem is diurnal. 9. Describe at least 5 challenges plants face in the alpine zone. Low temperatures Extreme temperature fluctuations Limited water availability High winds Less CO2 than at lower elevations High UV radiation Low nutrient concentrations in the soils stunted growth Very short growing season 10. Name and describe three specific ways alpine plants adapt to low water conditions Stomatal control – plants open their stomates at night only, preventing evapotranspiration during the day Succulence – plants have developed thick waxy leaves that store water CAM – plants produce acids to carry out photosynthesis without the need to open stomates for gas exchange during the day, when evapotranspiration is high Dessication tolerance Extensive below-ground biomass and root systems 11. In what ways does snow affect vegetation patterns in the alpine zone? Snow insulates against low or fluctuating temperatures. Snow protects against high winds and high radiation. Snow retains moisture for the soil and plants. 12. Describe osmotic adjustment To avoid the freezing of exposed tissue, plants increase the solute concentration in their cells. This allows them to lower the freezing point of the cells. 13. Give three reasons why frost action is likely to occur in mountain areas. Mountain environments experience extreme temperature fluctuations (rain can fall, trickle into cracks, and then freeze). There is a lot of exposed rock. The rock, because it has likely been folded, twisted, or upturned in some way, is composed of fractures, which facilitate frost wedging. (Lots of precipitation also accepted as an answer.) 14. Explain how vegetation (or revegetation) inhibits avalanching. Vegetation anchors snow and prevents sliding. If sliding does occur, vegetation can barricade the moving snow mass and prevent extensive drifting.