World Geography Midterm Review Guide

Transcription

1 1 World Geography Midterm Review Guide Land and Waterforms Compressional and Tensional Forces Compressional forces are caused when two tectonic plates are pushed together. Tensional forces are caused when two tectonic plates are pulled apart. Compressional forces force two plates together which form fold mountains because the lighter plate is pushed up over the heavier plate due to the folding and bending of the mountains. Tensional forces cause the plates to pull apart which makes one of the plates drop below the other which is known as a normal fault. Compressional forces cause the plates to be pushed together which makes one of the plates rise above the other which can be a part of an over thrust fault (folding occurs before the fault) or a reverse fault. Anticline = arch (upward fold) Syncline= sink (downward fold) Volcanoes A volcano erupts when thermals driven by the heat below the earth s surface force the magma up through the earth s crust causing an eruption or lava flow. Ridge Zones (areas where plates pull apart) and subduction zones (areas where plates push together) are the areas where volcanoes are prominent. Ash and Cinder Cones - very steep sides -violent eruptions - very tall -lava thrown high in air - ash and cinder falls back to earth

2 2 Shield Cones - fairly flat and broad - caused when molten lava flows out slowly - gently sloping - not usually very high Composite Cones -layers of lava mixed with layers of Ash and Cinder -intermediate height -explosive activity followed by quiet periods - ex: Mt St Helens Physical and Chemical Weathering Physical Weathering: the splitting of a rock without chemical change Chemical Weathering: rocks breakdown because of chemical reactions Physical Weathering Frost Fracture-water seeps into cracks, freezes, expands and break rocks Fluctuating Temperature- hot rock which leads to expansion, cold rock which leads to contraction Exfoliation- (flaky) internal pressure or external rain or dew causes rock to peel off Plant growth- rocks are forced apart by roots Animals Burrowing under ground- dig holes Chemical Weathering Solution(Corrosion) - rainwater absorbs chemicals from: A) Cars (Nitrous oxide) B) Industrial plants (Sulfur Oxide) C) Decaying plants and animals (organic acids) *Chemicals and rainfall= weak carbonic acid *Carbonic acid breaks down limestone and marble Hydrolysis -Carbonic Acid (water) reacts with silicate, sodium, magnesium and potassium ions and are dissolved and washed away and a soft clay is left behind Oxidation - Oxygen + Water + Iron-> yellow, brownish stain - Oxygen + Water + Copper -> Pale greenish color Stages of a River

3 3 Rivers change over time and seem to go through three stages: 1. Youth 2. Maturity 3. Old Age Youth (figure 2.7 p.28) o Are usually found in highland or mountain regions. o They tend to have a steep slope (high gradient) o Usually have a small volume of water o They have a rapid flow of water o There is usually very rapid erosion especially vertically o A narrow V shaped valley is characteristic o Waterfalls and rapids are common Maturity (figure 2.7 p.28) o Most high relief is eroded o Gentler slope o Many well developed tributaries o Broad flat river valley o Well developed flood plain o More lateral erosion than vertical o Meandering results o Late maturity occurs when these characteristics are all well displayed Old Age (figure 2.7 p.28) o Almost no slope o Very little relief o Elaborate meandering o Oxbow lakes develop o Often swampy areas around river o Very muddy due to slow speed o Most susceptible to flooding because of large flood plain. o Evaluating Evidence to Determine the Age of Rivers

4 4 There are six common pieces of evidence you can look for to determine the stage of a river. 1. Slope of the river (steeper = younger) 2. Relief of the banks (steeper = younger) 3. Width of the valley (wider = older) 4. Meandering (more = older) 5. Size of flood plain (wider = older) 6. Rapids or water falls (more = younger) Types of Erosion Vertical Erosion: downward erosion A) Hydraulic Pressure: force of water removes bedrock B) Corrosion: pollutants such as acids in water breakdown rocks C) Abrasion: Rock fragments scrape against and gouge one another Lateral Erosion: side erosion - rivers erode their sides or banks -meandering (bending occurs) Deltas Deltas are a low lying area found at the mouth of a river and are formed from deposits such as silt which has been laid down by rivers and settles there. Arcuate Delta: fan shaped or bow shaped (Nile Delta) Digitate Delta: finger shaped or birdsfoot (Mississippi Delta) Estuarine Delta: -Impacted by sea tides so that mud flats are left behind -formed when rivers run into a bay or estuary -tidal mud flats form which can be seen at low tide -sediment deposited from river outflow and from tidal inflow -ex: Notre Dame Bay Glaciation Alpine glaciation occurs in mountainous regions whereas continental glaciation occurs in continental areas (situated over large area of continent) Continental and Alpine Glaciation Terms Outwash Plain: Water flows from a melting glacier, these little rivers drop sediment with the larger rocks being dropped closer to the glacier. Terminal Moraine: End Debris, hills and lumps of debris at the end of a glacier which marks the glaciers last stationary point. Erratic: a large boulder which has been transported by a glacier and does not fit in with its new surrounding landscape. Drumlins: an egg shaped hill which was created by the glaciers bulldozing and debris being left behind as it re-advances. (Tapered end= direction)

5 5 Eskers: rocks that were deposited by a melting glacier, it resembles a raised river bed and a snake formation Cirque: A horseshoes shaped depression in the side of a mountain carved by a glacier Arête: the ridge where two cirques meet. Its very sharp. Hanging valley: high level tributary valley which has been cut off by another glacier Lateral Moraine: Side debris which is built up between sides of a mountain and a glacier. Fiord: A valley which has been created from a glacier and becomes flooded with sea water in between two high mountains. Drowning of a glaciated valley Coastal Erosion Sea Cave: A large hollow in the headland of a coast which is formed from waves attacking the rock and carving a hollow Sea Arch: Two caves on either side of a headland. It forms when the wall between the two caves breaks through creating an archway. Sea Stack: A pillar of rock in the water which is formed when a sea arch collapses Spit: a ridge of sand running away from the coast, usually with a curved seaward end. Bay Bar: a ridge of sand that runs from one side of a bay to the other Bay Beach: an accumulation of sediment deposited by waves and longshore drift along a bay An irregular coastline is straightened by wave erosion and the processes of abrasion, hydrolic action, and solution. Through longshore drift an irregular coastline can become straight over a period of time. Waves attack the headlands, eroding them and through longshore drift the sediment is deposited along the coast evening it out. Unit 2: World Climate Patterns Rotation-vs.-Revolution Rotation: The Earth rotates 360 o on its axis every 24 hours, giving us day and night Revolution: The Earth revolves around the sun, and makes a full trip round every days, this gives us our seasons combined with the earth s tilt (23.5 o )

6 6 Cloud Cover-vs.-No Cloud Cover When cloud cover is found in an area, it reduces the amount of sunlight and heat radiation that reaches the ground in the day, and also reduces the amount of heat that escapes into the atmosphere in space. Thus, the temperature does not have any dramatic changes in the run of a day. When there is no cloud cover, the sun intensely heats the ground in the day making it very hot, and at night all this heat escapes making it very cold. Therefore, an area with no cloud cover has a significant change in temperature between day and night. Equinox-vs.-Solstice Equinox: means equal day, equal night. It occurs on Sept 22 nd, and March 22 nd, and gives us the beginning of fall and spring. The sun shines directly on the equator on these two days. Solstice: means sun stop. It occurs on June 22 nd, the summer solstice in NH, and December 22 nd, the winter solstice in NH (opposite for SH). On June 22 nd, the sun shines directly on the Tropic of Cancer, whereas, on December 22 nd, it shines directly on the Tropic of Capricorn.] The Earth s Seasons The Earth s seasons are based upon the Earth s revolution around the sun and the tilt of its axis. The Earth is tilted at a 23.5 o angle, and when it tilts towards the sun we get summer, away from sun we get winter, and when its not tilting away nor towards we receive fall and spring. The revolution dictates which way the Earth will be in relation to the sun, and therefore the seasons. Difference in Seasons The Earth is tilting towards and away from the sun, the more it is tilted towards the longer the day because the sun shines on this region for longer times where is it more direct, whereas when the Earth is tilted away the sunlight only barely lights an area for a short period of time The angle at which the sun reaches the earth, and how direct it gets there affects temperature. This angle is depicted by location and the tilt of the Earth s Axis. More direct angle- more energy. Greenhouse Effect the capacity of certain gases in the atmosphere to trap heat emitted from Earth s surface, thereby insulating and warming the planet. Without the thermal blanketing of the natural greenhouse effect, Earth s climate would be about 33 C cooler too cold for most living organisms to survive. Temperature and Latitude

7 7 The further you are from the equator the lower the temperature. This is because the sun shines less directly on these areas and does not heat them as well, nor shine there as much. Earths Shape and Temperature The shape of the Earth allows for differences in temperatures as you go higher up in the latitudes due to its curvature. The curved Earth s surface makes the sun s energy shine at a more oblique angle at the higher latitudes making it spread its intensity across a larger area. Prevailing Winds A prevailing wind is the most dominant wind in a large area. Air always move from high to low regions Polar Easterlies(N AND S), Westerlies (N AND S), North and South East Trade winds The prevailing winds play a large part in what type of air mass is found in an area. For example, the North East Trade winds bring warm air from the equator where as the Polar Easterlies bring cold air to a region from the poles. Land Breezes and Sea Breezes A Land Breeze occurs during the night. Air cools and blows off the land towards the ocean. (water is warmer than land) A Sea Breeze occurs during the day. Air cools and blows off the water towards the land. (Land is warmer then water) Coriolis Effect The Coriolis effect is the tendency for objects or fluids to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere due to the earth's rotation (CCW) Types of Rainfall Orographic Rainfall: Warm moist air sweeps in over the ocean. It runs into mountains and is forced to rise over them. As it rises it cools and forms condensation and rain results. The cooler air passes over the mountain and down the other side creating extreme dry conditions. The rainy side of the mountain is called windward. The dry side of the mountain is called leeward. The rainy side of the mountain is called windward. The dry side of the mountain is called leeward. The dry side is also known to have a rain shadow because the clouds just pass over and drop little to no precipitation. Frontal Precipitation: Warm, moist air is forced to rise as it encounters a denser, colder air mass. The rising warm air reaches the condensation point clouds form and rainfall results. Convectional Rainfall: Precipitation caused on hot summer days, when heated land causes the air above it to rise by convection. As the warm air rises it cools

8 8 and condensation occurs. Rain or hail may fall from the thunderstorms that build up. Ocean Currents An ocean current is a permanent or semi-permanent horizontal movement of surface water (top 100m) Cold currents: colder air temps above land in nearby regions (normally less precip) Warm currents: warmer, wetter above land in nearby regions (normally more precip) Temperature Range and Continentality Temperature range is the difference in the highest and lowest temperatures The further in land a place is the less it is affected by the ocean and therefore has a greater temperature range. Continentality occurs in inland areas away from large bodies of water. In these areas there temperature ranges are very large, and they generally receive less precipitation. They generally have very hot summers, and very cold winters. This is due to not having the moderating effects of the ocean. The closer you are to the ocean, the more precipitation, and vice versa. Monsoons A Monsoon is the seasonal change in the direction of the prevailing wind. (summer breeze sea to land=wet, winter breeze land to sea=dry) Summer seasons are hot and wet in monsoonal areas because of the moisture being brought in by the prevailing wind over the ocean, and the winter season is very dry because the prevailing wind blows from the land. Elevation Elevation is the height above sea level Colder the air gets as it rises, the less capable it is of holding water therefore more rain. However, warm air near land is more likely to bring precipitation because of convection. Human Impact on Climate Global Warming Global warming is the gradual increase of the earth's average temperature since the i ndustrial revolution. It is a fact that the earth's average temperature is increasing. The negative effects associated witglobal warming is also factual. However, it is important to note that some scientists dispute the fact that it is due to human activity. Some scie ntists believe the recent increase in temperature is a part of the normal rhythms of cha nge in the earth's atmosphere. Global warming vs. Greenhouse effect It is also important to draw a distinction between global warming and the gree nhouse effect. The greenhouse effect is a good thing and moderates our tempe ratures here on earth. It operates by specific gasses like carbon dioxide and me thane. Global warming is due to the human activity that has increased the level of these greenhouse g asses and consequently increased the earth's temperature.

9 9 Human Impact on Greenhouse Gasses It is believed that humans have changed the balance of greenhouse gasses in th e atmosphere in two ways: 1.Increased carbon dioxide emissions: result from the combustion of fossil fuels. Coal, Gasoline, Furnace oil, Propane, diesel, and jet fuel are all examples of fossil fuels we bu rn and result in carbon dioxide emissions. 2.Cutting forests: results in fewer trees. Trees and all plants recycle carbon dioxide into carbohydrates consequently reducing atmospheric carbon dioxide. When these trees a re removed the level of carbon dioxide in the atmosphere increases. Global warming & Climate change Obviously global warming results in temperature changes. However that temperature ch ange affects precipitation as well. In some areas it increases precipitation and in other ar eas it reduces precipitation. Climographs A climograph is a graph that depicts the monthly temperatures (the line) and the precipitation (bars) for a particular place. Much info can be determined about a climate based on a climograph Keys to Understanding a Climograph: - line is temperature - Bars are precipitation - If temp line dips its SH - If temp line rises its NH - If flat temp line its near equator Climates Tropical Climates: - Always have temperature above 18 o C - Tropical Wet (Consistent Rain) -Tropical Wet and Dry (Seasonal Rain or Monsoonal) Dry Climates: - Less than 500mm of annual precipitation -More evaporation than precipitation -Arid: Less than 250mm -Steppe: mm, transitional zone Temperate Mild Winter Temperature varies with seasons Mid Latitudes Mild winter

10 10 Summer temperatures vary but winters are warmer than 3 Temperate Cold Winter Temperature varies with seasons Mid high Latitudes cold winters Summer temperatures vary but winters are colder than 3 Polar Climates Polar climates are distinguished by their extremely low winter temperatures and low s ummer temperatures. (not much vegetation) Tundra: summer temperature never above 10 C Ice Caps: summer's average monthly temperature is never above 0 Highland Climates These climates are only characterized by their elevation and decreased temperature because of that. However the climates vary with latitude of the mountain, closeness to the ocean etc. Some alpine regions can be like the tundra and the ice cap of a mountain is like the po lar ice caps. - For every 300m of increase in elevation the temperature decreases by 2 o C Unit 3: Ecosystems Ecosystems the relationship between living and non-living aspects of an environment. Ecosystems can very large(forest) or very small (under a rock) Food Chains and Food Webs Food Chain: A linear sequence which shows how various animals get their food energy Food Web: A series of overlapping and interconnected food chains Parts of a Food Chain:

11 11 How energy flows through an ecosystem The energy in any ecosystem comes from the sun. Producers in every ecosystem use this energy for their own purposes (85-90%) to create food, heat etc. When a primary consumer consumes a producer it receives approximately 10% of that producers energy, as we move up the trophic levels approximately 10-15% is passed on from one level to the next. Food Pyramid a diagram used to represent energy flows in a food chain or food web. Each level is called a trophic level. Why are their fewer organisms in each trophic level as we move up? There are fewer organisms in each trophic level as we move up because as we increase the trophic level, the organisms found in each are becoming increasingly bigger and need more energy to survive. In order for these organisms to survive they need to intake a significant amount of lower level organisms to meet their quota. Biological Amplification: It occurs when a toxin, chemical or pollutant is taken in by an animal in the lower trophic levels in a food pyramid and becomes amplified as it is passed up the food chain due to bigger organisms eating huge amounts of smaller organisms. A rat may intake 1 pesticide, and then a snake eats 4 rats (4p total) and finally a hawk may eat 4 snakes (16p total). It is clear, that due to the fact that these harmful substances are fat soluble (meaning the body can t break it down) toxins move very easily up a food pyramid. A Vegetation Climax Vegetation is the natural vegetation in the last possible stage of vegetation development. Climax vegetation is stable and in balance with the climatic conditions. It should change very little if left undisturbed. Ecosystems are largely defined by the climax vegetation that grows in it. The type of vegetation is largely determined by the climate. We will look at three major type of ecosystems found in high latitude regions. Look at figure 6.8 on page 102 of your text book and you will see the variety of ecosystems in the world. Coniferous (Boreal) Forests The climax vegetation in coniferous forest is Evergreen trees with: needle-like leaves; thick bark; conical shape; dense growing which blocks sun.

12 12 The location of the Boreal forest can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found only in the northern hemisphere and is located in a broad band across Northern North America and Northern Eurasia. Coniferous trees are well adapted to lack of water in winter (it is all frozen): needle leaves reduce surface area for transpiration; drooping branches and conical shape allow heavy snow to fall off relieving the pressure; thick bark reduces water loss. The climate in the boreal forest is temperate cold winter. Look at figure 6.8 on page 102 and locate the boreal forest; then turn to page 75 and locate the temperate cold winter (subarctic) climate region. The two match very closely. Tundra The climax vegetation in the Tundra is grasses, shrubs and low plants with: shallow roots; fast reproduction/flowering cycles. The location of the Tundra can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found only in the northern hemisphere and is located north of the Boreal forest across Northern North America and Northern Eurasia. The shrubs and bushes are well adapted to the extreme climate of the north where winter is long and summer is very short: shallow roots are needed because 1-3 meters below the surface the soil is completely frozen (Permafrost); the fast flowering and reproduction cycle is needed because the growing season is very short, lasting only 1-2 months. Animals have a variety of adaptations to the harsh Tundra climate. hibernation from the cold winter; migration in for the summer season and out for the winter season is a common strategy for Birds and even larger animals like caribou; the development of insulating features like thick fur & fat insulation is common among polar bears and other mammals; white fur/feathers to help with camouflage is another common adaptation. The climate in the Tundra is so definitive of the tundra that it is called Tundra climate. Look at figure 6.8 on page 102 and locate the Tundra; then turn to page 75 and locate the Polar (Tundra) climate region. The two match very closely. Polar Ice Caps The climax vegetation in the Polar Ice Cap is Phytoplankton beneath the ice. The location of the Polar Ice Caps can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found only in both hemispheres and is located only in the extremely high latitudes. The adaptation of producers to this ecosystem is extreme. There is no land for the producers to grow in so there are only small phytoplankton to form the base of the food chain.

13 13 Animals have a variety of adaptations to the harsh Polar ice cap climate. migration in for the summer season and out for the winter season is a common strategy for Birds and even larger animals like caribou; the development of insulating features like thick fur & fat insulation is common among polar bears and other mammals; white fur/feathers to help with camouflage is another common adaptation. The climate in the Polar ice cap is so definitive of the Polar ice cap that it is called Polar (ice cap) climate. Look at figure 6.8 on page 102 and locate the Polar ice cap; then turn to page 75 and locate the Polar (Ice cap) climate region. Temperate Grasslands The climax vegetation in Temperate Grasslands is grass with: shallow roots; a small water requirement. The location of the Temperate grassland can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found in North America, South America, Australia and Eurasia. Grasses are well adapted to lack of water: the small size of the plant means that it requires less water. The climate in the Temperate grassland is semi-arid in most locations but in some regions it is temperate cold winter. Look at figure 6.8 on page 102 and locate the Temperate grassland; then turn to page 75 and locate the semiarid climate region. The two match very closely. Temperate Deciduous Forests The climax vegetation in Temperate forests is deciduous trees like oak, birch and maple which: lose leaves in summer The location of the Temperate Forests can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found predominantly in North America and South America but is present in Australia and Europe and Asia. Deciduous trees are well adapted to lack of water in winter. losing their leaves in winter helps them reduce water loss. Most water loss occurs through the leaves. The climate in the Temperate Forest is temperate mild winter. Look at figure 6.8 on page 102 and locate the Temperate forests; then turn to page 75 and locate the temperate mild winter climate region. The two match very closely. Tropical Rain Forests

14 14 The climax vegetation in The Tropical Rain Forest is Tall Evergreen Broadleaf Trees with: Buttress roots. The location of the Tropical Rainforest can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found in South America, Africa, Australia and South East Asia and is contained within the tropics. The tall trees are well adapted to the thin soil with buttress roots (figure 6.15 on page 108) to help support their height. Some plants are epiphytes which are well adapted to the rain forest. They reach the sun by lying in the canopy while they get water through roots that hang in the air and absorb moisture. Some animals are adapted to spend their entire life in the canopy. The climate in the Tropical rain forest is Tropical wet in most locations but in some regions it is tropical wet and dry. Look at figure 6.8 on page 102 and locate the Tropical rain forest; then turn to page 75 and locate the tropical wet climate region. The two match very closely. Savanna Grasslands The climax vegetation in the savanna is grass with: shallow roots; small water requirement. The location of the Savanna can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found in South America, Australia, Africa and Southeast Asia. Grasses are well adapted to lack of water: the small size of the plant means that it requires less water. The climate in the Savanna is tropical wet & dry in most locations but in some regions it is semi-arid. Look at figure 6.8 on page 102 and locate the Savannas; then turn to page 75 and locate the Tropical Wet and dry climate region. The two match very closely. Deserts The climax vegetation in the Desert is cacti and fleshy plants with: long roots; water storage capability; leaves modified as needles. The location of the Desert can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found in North America, South America, Australia, Africa and Asia. Deserts are mostly concentrated in two bands around the earth North and South of the equator. Cacti are well adapted to lack of water. They are often referred to as Xerophytes: long roots help them obtain water deep in the water table;

15 15 water storage capability gives them the ability to endure long periods without rain; leaves modified as needles reduces the surface area for transpiration and helps reduce grazing which would severely increase water loss. Many animals have unique adaptations to the desert: deer mice can get all the water they need from the food they eat; toads have the behavioral adaptation of hibernating thorough the driest seasons; some Reptiles reduce water loss by excreting solid uric acid crystals instead of water containing urine; some mammals have the behavioral adaptation of nocturnal behavior, which keeps them out of the day time heat. The climate in the Desert is Arid. Look at figure 6.8 on page 102 and locate the Deserts; then turn to page 75 and locate the arid climate region. The two match very closely. Mountain Ecosystems Mountains ecosystems are not exclusively low latitude, on the contrary they occur in most latitudes and as you will see in figure 6.10 on page 104 mountains can contain all types of ecosystems from all latitudes. Figure 6.10 on page 104 well-illustrates the fact that latitudinal succession closely parallels altitudinal succession. The changes we see in ecosystems as we move north from the equator are generally, tropical rain forest, Temperate forest, Coniferous forest, shrubby tundra and then polar ice cap. The same changes in ecosystem can be seen as you move up a tropical mountain. Mountain ecosystems are not very unique they vary with altitude and temperature. Factors that Affect Soil quality: - Humus Accumulation (more humus- more fertile) - Leaching (too much leaching- low soil fertility) - Eluviation (too much eluviation- coarse soils result which aren t suitable for farming - Capillary Action (if capillary action occurs in small amounts, and there isn t a large amount of eluviation or leaching, the soil should be suitable for farming.) Quality of Soil based on its texture: Know how to read a soil texture chart The best soil is a loam texture which is a mixture of clay, silt, and sand. Clay: smallest, holds too much water, and doesn t allow air to penetrate Sand: largest, holds very little water, and does allow air to penetrate Silt: medium sized, holds some water, doesn t allow air to penetrate Global Patterns with soil loss:

16 16 While the earth's surface is covered in soil the amount of fertile soil valuable for agriculture is limited and is dwindling yearly. Poor soil management can lead to loss of fertile soil. Grasslands are semi-arid regions with extremely fertile soil. However, if proper soil management is not practiced these are among the most fragile places. Globally desertification of grasslands adjacent to deserts has been a problem. Agricultural land on slopes/hills or mountains are very susceptible to water erosion. Urban expansion has also been a factor in the loss of agricultural land. People have traditionally settled in rich farmland and increasing urbanization is covering up good farmland. Overgrazing, flooding and deforestation have also lead to the degradation of arable land. Distinguish between several farming strategies Other Tips Read the course outcomes to determine what you must know Read all notes, evaluations and review the textbook View old publics online ( Cdli is an excellent resource for review (