Geography Exam 3

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  1. Describe how snow transforms into glacial ice.
    Heavy snow falls during winter 

    Snow does not completely melt during the summer– takes hundreds to thousands of years

    snow accumulates annually in layers • equivalent to layers of sediment in sedimentary rock
  2. Know how glaciers form
    • Formation
    • 1: Snow falls, 80% air, new snow piles on top of old snow.
    • 2. Snow compacts, melt and freezing cycles, becomes firm
    • 3. Air is almost completely squeezed out, more than 40m deep, begins to flow
  3. How glaciers change in size (glacial mass budget)
    Inputs - Snowfall

    Outputs - Melting, evaporation and sublimation
  4. Inputs
    • Annual snow fall exceeds melting, evaporation and sublimation

    • Accumulation of ice from snow fall

    • Zone of accumulation
  5. Outputs
    • • Higher temperatures down the valley
    • • Melting and evaporation exceeds snowfall
    • • Zone of ablation
    • • The boundary between the zones of accumulation and ablation is called the equilibrium line– Inputs and outputs are in balance
  6. Know the 2 ways that Glaciers can move
    Plastic Flow: Glaciers flow under their own weight.

    Basal Sliding - Pressure from weight of glacier melts small amount of water under the glacier
  7. Cirque Glacier (Alpine)
    Form in bowl-shaped depressions high on mountains

    Feed into larger glaciers
  8. Valley Glaciers(Alpine)
    Glacier flows in steep-sided valleys that were originally carved by streams
  9. Piedmont Glacier(Alpine)
    Glacier extends entirely out of the valley into the lowland in front of the mountain

    Leaves narrow valley for flat lowlands so spreads out
  10. Tidewater Glacier(Alpine)
    Glaciers that terminate at the ocean or sea
  11. Continental Glaciers
    • • Huge ice mass that covers a large part of a continent or large island – Also called ice sheets • Once covered much of North America and Europe
    • • Now confined to Greenland and Antarctica
    • • Several thousand meters thick
  12. Explain how glaciers erode the landscape and the different landscape features formed by
    • 1. Abrasion (like sandpaper) - Sand or fragments of bedrock frozen to the bottom of the glacier – Fragments grind down the underlying bedrock
    • • Creates glacial striations– Scratches that indicate the direction of glacial movement

    •  2. Plucking -
    • • Glaciers loosen, pick up, and remove parts of larger blocks of rock
    • • Rocks or boulders that are picked up are dropped later in random locations – Known as glacial erratics– E.g. Sioux Quartzite (bedrock from SW Minnesota) now found in Nebraska and Kansas
  13. Glacial Moraines
    • Ridge-like feature that forms at the front, side, or in-between glaciers

    • Forms only when a glacier is stationary for a while – Internal movement of the ice continually brings forth sediment for a ridge to grow

    • Sediment is unsorted
  14. Know the most recent periods of glaciation on Earth.
    • PreIllinoisan– Numerous glacial advances and retreats that are difficult to separate so lumped together as PreIllinoisan

    • Illinoisan– 300,000 years ago

    • Wisconsin– 35,000 to 10,000 years ago – covered 30% of Earth’s land surface, vs. 11% today
  15. Lateral Moraines
    Forms along the edge of a glacier • Most easily seen along the edge of alpine troughs
  16. End Moraines
    Form at the front of the ice

    Mark the furthest advance of the glacier where it was stationary
  17. Ground Moraines
    • Form when retreat of ice is slow but steady (warm and melting)

    •Irregular pattern of deposition

    • Landscape is hummocky (small hills and depressions)
  18. Drumlins
    • Developed by a range of glacial processes • Composed of till

    • Show the direction of ice flow
  19. Outwash Plain
    • Flat landscape created by deposition of sediments carried by glacial melt water flowing in front of the glacier

    • Glacial streams are full of coarse sediment – braided streams
  20. Kettle Lakes
    • Large blocks of ice melted and fell of the front of glaciers

    • Ice buried by glacial outwash sediment as glacier retreats

    • Ice melts and outwash sediments sink --> forms a lake – Lake will remain if it intersects the water table
  21. Describe what soil is
    • Uppermost layer of the Earth’s surface capable of supporting plants, formed from minerals (weathered rocks) and organic matter
  22. 4 main components of soil
    1. Inorganic Material -Minerals that come from weathered rocks – Crystalline structures depending on the rocks they originated fro, Minerals contain different elements that are essential for plant growth – Released via weathering and absorbed by the plants.

     2. Organic Matter 

    Formed from living and decayed organisms, accumulates in the upper part of the soil as humus. 

    Increases soil material because microbes decompose plant material – Release essential plant nutrients

    Decays faster when there is oxygen present (aerobic decomposition), and slower when there is no oxygen because the soil is saturated (anaerobic decomposition)

    • 3. Soil Water - Fill with water – At capacity = saturated– Drains to groundwater under gravity – Water drawn upwards via capillary action
    •  • Water held to soil pores due to surface tension 

    4. Air
  23. Describe how soil is formed over time
    Organisms, relief, time, climate, parent material.
  24. Four major processes that influence soil development
    Additions - Organic matter, Precipitation Minerals and sediments solar radiation, O2 and CO2

    Depletions - Sediment, Soil water, Organic matter and Soil minerals

    • Transformations - Organic matter -> humus Minerals -> other minerals
    • Minerals -> smaller sizes
    • Soil particles clump together
  25. What is a soil profile?
    a vertical section of the soil from the ground surface downwards to where the soil meets the underlying rock.
  26. what do the different soil horizons represent?
    Distinct, genetic layers.
  27. Entisols
    Soils of recent origin 

    • Contain no horizons except A horizon

    • Reasons for lack of development – Climate is very dry – Parent material is quartz sand, which is very resistant to weathering – Parent material has been recently deposited, so little time for soil forming processes
  28. Mollisols
    • From Latin mollis, "sok”

    • Soils of grassland ecosystems

    • – Great Plains of the Midwestern U.S.
    • – Broad region of Eurasia, including Russian steppe – Pampas of South America
  29. Alfisols(Forest Soils)
    • • Cooler climates
    • • Clay-enriched B horizons (illuviation)
    • • High concentra<ons of Al and Fe ions
    • • Thinner A horizon than mollisols
  30. Histosols
    • • Soils that are composed mainly of organic materials – at least 20-30% organic matter by weight and are more than 40 cm thick
    • • Form in wet sites – Organic matter decomposes slower under water (anaerobic decomposition)
  31. Vertisols
    • - Very high clay content
    • – Swell when they are wet and shrink when they are dry
    • – Strong structure
    • – Constant mixing of soil horizon when cracks form
  32. Gelisols
    • Occur in very cold climates—high latitudes or high elevations
    •  Contain permafrost within 2 m of surface and large quantities of organic carbon
    • Low soil temperatures cause soil-forming processes such as decomposition of organic materials to proceed very slowly              
    • Poorly formed B horizon
  33. What is the major soil order in the Midwest
    and in Illinois?  How has that impacted
    land use in this region?
    Mollisols; it has made the production of agriculture skyrocket.
  34. Understand what controls the distribution of plants and animals on Earth
    Tolerance to the environment - CAN it survive here?

    Competition - WILL it survive here?

    History / seed sources / migration

    If out-competed… organism cannot survive to reproduction age or it cannot reproduce even if old enough

    Main things animals compete for: food, shelter

    Main things plants compete for: nutrients, water, light
  35. Two types of Succession
    Primary Succession:no soil (and hence, no previous plants either)

    Secondary succession: after a disturbance(disturbance destroys previous plant community)(soil remains)
  36. Understand pioneer communities and characteristics
    Pioneer species = wind dispersed seeds

    Characteristics: light, wind, soil, moisture, temperature, seeds. Replaced by other species. 

    Aspen: common tree species
  37. Climax forest
    • -Shady 
    • -net change in species number or type is minimal
    • -diverse (many species)
    • -seldom attained (takes too long), disturbance is the rule
    • -Light
    • -Wind tolerance
    • -Moisture needs
    • -Temperature tolerance
    • -How are seeds dispersed?
  38. Plant Succession
    • Changes during succession
    • -increasing numbers of plants that can tolerate -low light
    • -more diversity
    • -more layering/stratification
  39. BIOMES
    Biomes are the world's major communities, classified according to the predominant vegeta1on and characterized by adaptations of organisms to that particular environment.
  40. How does climate influence plant type?
    Temperature & Moisture.
  41. Tropical Rainforest
    Appears very dense from overhead

    • –Relatively open and dark near forest floor
    • –Only dense vegetation on the floor

    • near rivers and on slopes because light can get in
    • soils: red, nutrient-poor Oxisols 

    • -Most nutrients are tied up in biomass, not soils
    • -Extremely rapid nutrient cycling
  42. Savanna
    -too dry for forest
  43. Desert
    • -not a function of temperature
    • -high annual moisture deficit combined with low actual evapotranspiration
    • -There are many COLD deserts!
    • -Most deserts are dominated by woody shrubs/scattered grasses
  44. Tundra
    • -Temp of warmest 3 months averages less than 45 degrees F 
    • -Too cold for trees
    • - lowest diversity:mosses, lichens, grasses, sedges dominate
  45. Plant Adaprations
    • -low growth habit (already discussed)
    • -Perennials
    • -can photosynthesize at -10C
    • -seeds may take 2 years to produce (flower one year, produce seeds the next)
    • -underground food storage
    • -dark colors and pigmentation,raises temperature by absorption
Card Set:
Geography Exam 3
2014-12-04 08:00:29

Geography 101
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