HONORS GEOGRAPHY: LANDSCAPES AND WATERWAYS

GEOGRAPHY NOTES 3 LANDSCAPES & WATERWAYS - Introduction - Geographers need to know how the earth looks and why - also need to know what it means for the people living there - earth’s surface is divided into two parts - land, water - land portion is divided into lots of different shapes - wrinkled, broken, warped, worn - these shapes are called landforms -together w/soil and plants they make up what covers the earth - because we live on land, we forget that water covers most of the earth - and like landforms, waterways have a variety of shapes/sizes - the patters of these two parts influence how we live - where transport routes are built - how to make a living - this is why we have to study this in geography - natural landscapes - these are landscapes formed by nature - made of of landforms, soil and plants - but landforms are the basic elements of natural landscapes - give the land its shape and influences where plants grow - major landforms are landforms that are quite large - plains, plateaus, mountains, hills - plains: large area of mostly level land - most are no higher than 1,000 feet above sea level - also, altitude changes gradually - some are called coastal plains - they lie near the ocean - ex: Gulf Coastal Plain of U.S. - begins at edge of Gulf of Mexico - goes as far north as Illinois - highest point is less than 500' - plains found on all continents except Antarctica - one of the largest is the Great Plains of N. Am - begins in Canada and ends in Texas - this is example of inland plain - sometimes they’re called high plains - Great Plains slop east from Rockies - at base of mtn, plains 2000' to 5000' asl - they slope so gradually hard to see it - in Europe, North European Plain - from France to Russia - in South America the Pampas area of Argentina - there are many other plains all over the world - plateaus are raised plains covering a large area - rising steeply from the ground up - at least on one side, sometimes both - they are sometimes called mesas or tablelands - some have steep cliffs on one or more sides - w/ mountains and hills on the other sides - ex: Bolivian Plateau in S. Am. - there are plateau areas on most continents - much of Africa is made up of plateaus - in N. Am. one stretches from Ctl Mex. to Canada - Colorado Plateau of US is part of it - highest tableland in the world is Plateau of Tibet - ranges from 10,000 to 15,000 feet asl - mountains defined as have an elevation of at least 2K’ -w/ fairly steep slopes and small summits or tops - very high mtns have different life zones - that change as the altitude increases - ex; Mt.Rainier in WA - many trees at base - higher up, less growth - trees and small plants - this is called the timber line - farther up nothing grows - b/c of high alts., it is very cold at tops - often covered in snow - glaciers, rivers of packed ice, form here - highest mtns in world are Himalayas in Asia - w/highest mtn. in world Mount Everest - 29,028 feet, almost 6 miles high - Andes in So. Am form longest mtn chain in world - 4,000 miles from top to bottom -another mtn chain runs thru Mex. into Canada- the Rocky Mtns - there are important mtns in other countries - the Alps of western Europe - France, Switzerland, Italy and Austria - Africa has few mtn systems - one of the largest are the Atlas Mtns of NW - Australia also has few mtns - and none are very high - many mtns in Antarctica are covered w/glaciers - forming plateaus of ice - there are four major types of mtns - folded caused by upthrusts of earth’s crust - Appalachian mtns in East - fault block huge blocks formed by pressure - and break into separate pieces of fold - Sierra Nevada of CA - dome also created by upthrust - but d/n break or fold - Black Hills of N.Dak - volcanic happen when earth’s crust cracks - molten material is blown out or flows - lava and ashes piled in layers - sometimes high enough to be mtn - May 1980 Mt. St. Helens - Mt. Fujiyama in Japan - hills are fourth major landform - rise above the ground but lower than mtn - range in elevation 500-2000 feet asl - Black Hills of S. Dak are not hills but mtns - hills can be found everywhere in the world - Antarctica, covered by ice - minor landforms - there are way too many to list - they make up small details of major landforms - giving each local area its individual look - the way eyes and wrinkles give people individual look - it’s what makes a hill in New Eng. diff from one in Brazil - might include a valley a section of land b/t to higher areas - deltas low lying land formed by soil deposited by rivers - tidal flats sandy beaches or muddy land formed by tides - all of these give details to the different places and landforms - shaping of landforms - forces inside the earth help structure the land - scientists see the world in three parts - outer part is the crust b/t 10-25 miles thick - below that is the mantle some 1,800 miles thick - made of hot rocklike material - at the center is the core - inner core is solid iron, nickel - outer core is molten - temps range from 4000' to 5000' - heat causes materials in mantle to rise up - creating pressure on crust - if enough pressure could rise, fold or break - this is called diastrophism - sometimes lava flows out of the earth - sometimes slowly - other times with a tremendous explosion - either way, this is called vulcanism - and mtns made this way are called volcanoes - forces on the surface also shape the landforms - one is called weathering - breaking up of rocks into smaller pieces - can be a long slow process - if done mechanically, by pushing or rubbing, it is called disintegration - ex: water leaks into/between rocks and freezes - ice swells causing rocks to crack or break - if weathering is done by chemical action it is called decomposition - chemicals in air, water, and in rocks combine to break rocks - surface is also changed by erosion - means that pieces of rock are carried away - as they move, they grind at others, making more changes - forms or agents of erosion are those things that cause it - moving water, wind, moving ice - glaciers are large rivers of moving ice - inching forward down into alleys - grinding away the earth’s surface - third shaper of land is deposition - as erosion carries rock away, it deposits material in other places - piling up, layer after layer, to make minor landforms - ex: sand dune - sand carried by wind pile up - low places of land are often filled by deposition - soil - second most important element in landscape - one kind may be totally different from another kind - can see this in plowed soil - sometimes rich, brown in color - thick and heavy with nutrients - sometimes shiny black, breaks easily into smaller chunks - sometimes its very sandy - these differences are due to materials which nature produced - which forms the soil - despite the differences in appearance, all soil is made of same basic elements - a mixture of several things - basic part is rock material - but also minerals and organic matter - living or dead plants - plus air and water - most soil is made up of three layers - top layer is called humus - tree leaves, dead, decaying, rotting plants and animals - second layer is what is washed down from top layer - rain does most of the work - but roots also work at this level - they release chemicals into the soil - small animals burrow into the soil - allowing air and water to collect - third level is called parent material - solid rock from which soil is “born” - weathering of parent material contributes to 2nd layer - each of these layers determine what soil is produced - chemicals and minerals also play a part - in many areas of the world, the soil has no humus - sometimes no soil at all, just bare rock - composition of soil determines what to grow there - we call this the fertility of the soil - some are rich, some fair, still others useless - the different types of soil come in five categories - and they occur over large areas or zones of the surface - that is why they are called zonal soils - one kind of zonal soil is lateritic soil - recognizable by its reddish or yellowish colors - found mostly in hot temperatures all year round - high temps and a lot of rain help decompose organic mat. - however heavy rains leach (dissolves) minerals - food for the plants - these soils contain very little humus - found in much of Brazil, Ctl-West Africa, S/SE Asia - and N. Australia - heavy use of fertilizer is needed for good crops - another zonal soil is podzolic soil - Russian word for “ash-colored” - found in forest regions of N. N America, Europe, Asia - b/c of cool temps, humus forms very slowly - since soil receives lots of moisture, minerals are leached - this soil, too, has rather low fertility - third zonal soil also comes from a Russian word - Chernozem but also called Prairie Soil - b/c occurs mostly in regions of grasslands or praries - chernozem means “black earth” - it has lots of humus - soil is very black at the surface - getting lighter the farther you go down - it is only slightly leached and very fertile - found in central N. Am., Pampas of S.Am., and ctl USSR - fourth zonal soil is desert soil - where there is little, if any, rain - desert soils contain little to know humus - since there are few plants to decompose - but on other hand, there is little leaching - also parent material contain lots of minerals for plant food - they can be quite fertile when water is brought to them - by canals or pipes - this is called irrigation - the Imperial Valley of CA is an area of desert soil - it produces a huge amount of crops - corn, grapes, cotton, fruit, etc. - the Negev Desert of Israel is another - there are several large areas on earth where desert soils are - Western US, Sahara, SW Asia, W.Ctl. Part of Australia - last zonal soil is cold-land soil - where temps are low throughout the year - here, soil formation is low - b/c of low temps, the soil layer u/g is permanently frozen - Permafrost - only when ground layer over permafrost thaws can plants grow - when that happens the soil beome quite fertile - N. Can., N. AK., N. Europe, Asia - plants - with landforms and soil, landscapes are also made up of plants - it’s usually the first thing you notice - they are necessary to support human and animal life - both directly and indirectly - the distribution of plants depends on the landforms, soil and climate - plants, like people, live in communities - ex: a forest with trees, vines, bushes, grass, mosses - some communities have many different plants - ex: tropical areas - some, like deserts, have very few communities - each area of the earth has a plant community best suited for its conditions - of soil, climate, and landforms - ex: a fire destroys a certain forest area - at first, only grasses would grow - then bushes would return, and later, trees - plants not suited to the area would be pushed out by newer plants - this is called succession - eventually the community is established which is best suited - unless some drastic change takes place, it stays that way - this last process of succession is called a climax community - distribution of plants can be considered in three categories - forests, grasslands, dry areas - different forms of plants live in these different areas - but ea. category is different b/c in ea. a particular plant is important - in forests, trees are most important - although grass and other plants grow there - in grasslands, ....duh - though some trees grow in grasslands but are scattered - certain plants even grow in dry areas like cactus, agave, etc. - even some grasses grow, but few trees like creosote - there are several different kinds of forest communities in the world - much of the eastern half of the US was once total forest - made up of trees w/broad leaves like maple - which fall off in the winter and rtn in warm spring - these are called deciduous trees - in SW US forest was largely pine trees having needles and cones - because they have cones they are called conifers - and because they keep their leaves (needles) all year round - they are called evergreens - much of Europe was covered w/trees like the US - both breadleaf deciduous and evergreen conifers - Asia and Japan was also covered in these trees - today, most evergreen and coniferous trees c/b found in Canada, N. Europe, and Russia - broadleaf evergreen forests are found where temps are high - and there is abundant rainfall - called tropical rainforests - found in Brazil, Ctl. & W. Africa, and SE Asia - in addition to diff. forest communities, there are three kinds of grasslands - prairie, steppe, and savanna - prairie: continuous mat of tall grass sometimes 2' high - E. plains of N. Am u2b a prairie - pampas region of Argentina - steppe: prairies that get much less rainfall - mat of grass is much shorter - W. Great Plains is a steppe - largest steppe region in the world is in Central Asia - savanna: areas with little or no rainfall for part of the year - grasses grow in clumps instead of a mat - widely spread trees also grow - acacia - largest savanna in the world is in Africa - other large areas in Ctl. Brazil, and N. Australia - dry vegetation areas receive even less rain than savannas - one is a desert - in some like Am. west, widely scattered clumps of grass - plus small shrubs and plants like cactus - in very dry areas, like the Sahara, there are few or no plants - the other is called a tundra - an area where cold temps all year prevent much plant growth - maybe a lot of water around, but most of it is ice - plants can’t use it unless it thaws - vegetation consists of lichens and very short shrubs - found mostly in northern N. Am., and Asia - the distrib.of plant communities affects distrib.of animal communities - ex: deserts support snakes, lizards and small rodents - forests support bears, elk and mountain lions - geographers have a name for this combination of plants and animals that exist in one area - they call it a biome - because there are many different soils, climates and plant communities - there are different biomes as well QUESTIONS- 1. Name the four major landforms 2. What are the three parts which make up the earth’s structure 3. Explain the things which combine to produce soil 4. What are the three major categories of plant communities?