ANSWER KEY Geographic Issues of the 21st Century Unit 1-The Physical World

Transcription

1 ANSWER KEY Geographic Issues of the 21st Century Unit 1-The Physical World Part 1: Creating the Continents Textbook pages Explain the ideas of continental drift and plate tectonics. How do these theories relate to the physical layout of land on earth today? In 1915 a German Scientist by the name of Alfred Wegener suggested a theory of continental drift. He suggested that 300 million years ago the earth's continents were in constant motion and collided to form a supercontinent Pan gea. His proof: - Jigsaw fit between South America and Africa - He found the same animal fossils on both continents - Mountains similar in age and structure - Ice sheets covered places that would be too warm today to form Alfred's theory was dismissed because there would be no known (at that time) force that could move these large land masses. Until Canadian J. Tuzo Wilson who in 1968 developed the theory of plate tectonics (which today explains most geological processes). Plate Tectonics states that the Earth's outer shell is made up of about 20 plates. Most of these plates are made up of both a continent and an ocean. They are moving over a weak layer of hot rock, several hundred kilometers below the earths surface, which flows like slow-moving plastic. Forms: Mountains, fossil fuels (oil, gas and coal) etc. 2. Define the terms "folding", "faulting" and "erosion". How has each of these processed contributed to the earth's physical landscape? (diagram p. 87) Folding: (uplifting) Enormous pressure caused the earth to buckle. Faulting: The earth cracks open. (contributes to the formation of mountains) These two buildup the landscape Erosion: Wind, rain, running water, glaciers, temperature changes and chemical reactions erode the land.

2 3. What is the rock cycle? Draw a simple diagram of the rock cycle (p. 88) and exp difference between igneous, metamorphic and sedimentary rocks. The rock cycle is a model that describes the formation, breakdown, and reformation of a rock as a result of sedimentary, igneous, and metamorphic processes. Sedimentary rocks are formed by sediment that is deposited over time, usually as layers at the bottom of lakes and oceans. Igneous rock is formed when magma cools and solidifies, it may do this above or below the Earth's surface. Metamorphic rocks are formed by pressure deep under the Earth's surface, from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

3 ANSWER KEY Geographic Issues of the 21st Century Unit 1- The Physical World Part 2: Landforms Textbook pages What is the Canadian Shield (aka the Precambrian shield)? What forces contributed to its formation? Why is it a significant landform in North America? Canadian Shield is the geographic foundation of Canada. More than half of canada is covered by the shield. Minerals were present in magma (molten rock) beneath the earth's crust. As magma rose towards the surface it forced its way into the cracks and cavities in the shield rock. As it cooled some minerals were deposited in the magma itself. Other deposits were formed when minerals dissolved in hot water and were forced into cracks of the surrounding rock. This process allowed minerals to be deposited in high concentrations. It is significant because of the vast deposits of lead, gold, nickel, copper, zinc and other important metals (storehouse of Canada's metallic minerals). 2. Define "highlands" and "lowlands". Lowlands: A massive region surrounding the Shield. The bedrock under these lowlands was formed from mainly sediments eroded from the Shield and compressed into sedimentary rock. Highlands: A region that lie to the east, north and west of the Shield. Mountainous areas, the Appalachians, the Innuitians and the Western Cordillera. 3. Name the 4 different lowland areas in Canada. Explain how differential erosion has shaped the lowlands. What major physical feature was created as a result of erosion? Interior Plains: Covered by shallow inland seas, sediments were deposited from the shield and Rocky Mountains, some formed coral reefs which were compressed under the surface into much of the oil and gas found in Alberta and Saskatchewan. Potash (nutrient rich fertilizer) is mined from thick layers of dried-out sea beds found in Saskatchewan. Erosion has caused different levels of elevation on the prairies separated by an

4 escarpment*. Composed of rolling hills and deep wide river valleys. Glaciation created Lake Winnipeg, Lake Manitoba, Lake Winnipegosis and Cedar Lake. Great Lakes-St. Lawrence Lowlands: Escarpment,niagara falls, rolling landscapes, (soil, sand, gravel), flat plains, rolling hills, deep river valleys, Great Lakes (gorged out by glaciers). Hudson Bay-Arctic Lowlands: HB: Flat, low area covered by swampy forests, AL: series of islands, rolling landscape. lignite (form of coal), oil, natural gas. Coastal Lowlands: Similar to Interior Plains other than location and lower elevation, valley of the Mississippi, flat rich soils, salt, oil and phosphate rock. *Sharp rises in elevation formed when a harder rock layer overlays a softer layer resists erosion. 4. Identify Canada's 3 highland areas. What geological forces were responsible for their creation? Appalachian Mountains: Oldest highland region, layers of sedimentary rock were uplifted and folded when North America collided with Europe and northern Africa. Volcanic activity and faulting created igneous and metamorphic rock, Plateaus contain metallic minerals such as zinc and iron. Millions of years of erosion have reduced the Appalachian '5 to rolling mountains and hills with wide glacial valleys. Long bays were created and provide deep harbours. Innuitian Mountain: Formed when the North American plate moved northward. Igneous and Metamorphic rock. Have not been rounded into hills from erosion like the Appalachian Mountains. Barren and covered by ice and permanent snow. Western Cordillera: Western edge of the continent like a great wall separated by plateaus and valleys. Little flat, coastal land exists. Great height and rugged appearance (geographically young). The collision of the North American and the Pacific plates is responsible for uplifting this region into several mountain ranges. The heavier Pacific plate forced its way under the lighter North American plate causing much folding, faulting and volcanic activity. 3 divisions: Eastern Mountains (Rockies & Columbia), Interior (Okanagan Valley) Plateaus and Coastal Mountains (Coast Mountain Range and the Island Mountain Range).

5 Geographic Issues of the 21st Century Unit 1- The Physical World Part 3: Glaciation Textbook pages Define the following glacier-related terms: a)till b)striation c)moraine d) drumlin e) lake plain till - eroded material deposited directly by the ice of a glacier. striation- a groove often gouged out in the bedrock under the ice sheet by rocks frozen in the ice. moraine- material deposited by a glacier often in the form of a hill. drumlin- geological formation formed by ice sheets an egg shaped hill with a steep side at the wide end and a gentle slope at the other. lake plain- fertile bottom of an ancient glacial lake used for agriculture. 2. a) Explain how a period of glacial activities activity begins. Begins when the earths climate cools, and the snow that falls in the winter does not completely melt in the summer. b) What causes snow to turn to glacial ice? Over thousands of years the snow gets deeper and becomes hundreds or thousands of meters thick. The tremendous weight of the snow on the top causes the bottom layer to turn to ice. c) What causes alpine and continental glaciers to flow (how does each type move?) Alpine glaciers- move from high elevations to lower elevations because of gravity. Continental glaciers- move under their own weight. The weight of the snow and ice cause the ice to spread outward.

6 3. Explain how and why materials like rocks and sand (glacial till) are deposited by the movement of glaciers. As the ice sheets moved they eroded huge amounts of soil, sand, gravel and rock. Deposited directly by the ice sheet. Rivers flowing within or under melting ice carried sand and gravel along with them and laid it down in river beds. 4. State 2 impacts glaciation had on the Canadian Shield. striation (grooves in the bedrock) valleys drumlin moraines eskers lake plains bare rocks and bent trees

7 ANSWER KEY Geographic Issues of the 21st Century Unit 1- The Physical World Part 4: Weather and Climate Textbook pages Explain the difference between weather and climate. Give 3 examples of how it affects our lives. weather- day-to-day characteristics of atmospheric conditions (temperature, humidity, precipitation, wind speed and direction, cloud cover, air pressure) climate- A long term pattern of weather. weather- ball game, clothes to wear, activities. climate- buildings, where we live, vehicles 2. Define "continental climate" and "maritime climate". List 2 Canadian cities that are found in each of those climate regions. continental climate- climate type that develops away from the influence of an ocean. The annual temperature range tends to be large and precipitation is low. Winnipeg, Regina. maritime climate- climate type that is strongly influenced by the closeness of an ocean or other large water body. The annual temperature range tends to be small and precipitation high. Vancouver, St. Johns. 3. Define the following terms: a) air mass b) front C) prevailing winds d) jet stream air mass- a large volume of air with the climate conditions of the area where it was formed. front- leading edge of air mass. If the air mass is warm the leading edge of air is called a warm front. Vice versa for cold front. prevailing winds- winds that are most commonly found in an area. jet stream- west to east movement of air in the midlatitude flowing at speeds of up to 400km/h at an altitude of between 8000 and m.

8 4. Explain how latitude affects climate. As latitude increase temperature drops, cooler climate. Temperatures drop the further an area is from the equator due to the curvature of the earth. In areas closer to the poles, sunlight has a larger area of atmosphere to pass through and the sun is at a lower angle in the sky. 5. "Bodies of water have a moderating effect on land temperature". Explain how this process works. Large bodies of water heat up and cool down more slowly than land masses. Summer the water stays cooler and wind blowing across the water cools the surround area down. In winter the water retain more heat and therefor wind blowing across the water heats up the surrounding area. (cool summers and warmer winters: moderated temperature and climate). 6. How are ocean currents and climate related? Ocean currents affect the temperature of the air that passes over it. Warm ocean currents ie North Pacific Currents are responsible for the mild climate of BC. Cold ocean currents ie Labrador Current responsible for the cooler climate in Newfoundland. Where two ocean currents meet more foggy and damp climate. 7. In what ways do prevailing winds affect the movement of air masses? How does the polar jet stream influence the movement of air masses? Move air masses that affect our weather, it is the boundary between cold & dry polar air and warm, moist tropical air. High above the polar front, it is a current of air that flows from west to east. During winter the boundary between cold and warm air moves southward allowing cold arctic air to flow farther south into the United States. In summer it moves northward allowing warm air to flow farther north from the Gulf of Mexico into Canada's interior.

9 8. State 3 conditions that cause air to rise. What happens to the temperature and moisture content of air as it passes over a mountain? 1. It rises to cross an area of high elevation. Relief precipitation. 2. It rises because it has absorbed heat from the Earth's surface. Conventional precipitation. 3: It rises because there is a cooler, denser air mass flowing beneath it that forces it up. Cyclonic precipitation. As moist air rises up the windward side of a mountain range it expands and cools. Coo/ air is able to carry less moisture therefore the rate of condensation increase and precipitation forms.

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11 ANSWER KEY Geographic Issues of the 21st Century Unit 1-The Physical World Part 5: Soils and Natural Vegetation Textbook pages Define the following soil-related terms: a) parent material b) topsoil c) soil profile d) humus e) loam parent material- rock from which soil is derived. topsoil- surface layer of soil. soil profile- different horizons (layers) in the soil and the rock layer (bedrock) below the soil. each layer has a different physical, biological and chemical characteristics. humus- dark, upper layer of soil made up of partially decayed plant material. loam- rich, fertile soil in which decaying and decayed plant matter is mixed with clay, silt and sand. 2. Soil is made of 4 basic components. Name them. Minerals, bacteria and organic material, air, moisture. 3. Describe how topsoil is formed. Why are there different types of topsoils in different parts of Canada? Slow weathering of parent material under the forests and grasslands of Canada. Because of climate, mainly precipitation: more precipitation (leaching). Less precipitation (calcification). 4. Explain the difference between leaching and calcification. leaching- continued downward movement of water through the soil. As the water moves down it dissolves the chemical nutrients in the soil and carries them around. This removes the nutrients that the plant need. calcification- water evaporates and the water from below is drawn to replace it. As the water evaporates it leaves behind minerals which results in the creation of a thick topsoil layer that is rich in minerals.

12 5. Define "natural vegetation". Explain why the following quote is true: "Natural vegetation is usually quite different from plants that people cultivate for food or use in industry" natural vegetation- refers to plants that grow without any human interference. Natural vegetation grown in response to different climate and soil conditions. 6. Describe the characteristics of the following types of natural vegetation: a) boreal/taiga forest b) coniferous forest c) deciduous forest d) mixed forest boreal/taiga forest/coniferous forest- They are able to extract nutrients from the poor soil with their long roots. Sticky sap acts as an anti-freeze which prevents the needles from freezing. Waxy needles and thick bark prevent the loss of moisture in times of drought. Needles and flexible branches easily shed snow to prevent damage. Needles are able to conduct photosynthesis on warm days beyond the normal growing season. deciduous forest- Lose leaves in autumn. Dormant in winter but with the warmth of the spring the sap flows to the buds causing new leaves to grow. Need a minimum of five months with an average temperature above 10*C. mixed forest- Coniferous and deciduous trees. 7. What is a transition zone? Area where the characteristics of one region gradually change into those of another.