Hello, can somebody help me answer these questions please....thank you very much
ID: 105615 • Letter: H
Question
Hello,
can somebody help me answer these questions please....thank you very much
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(Minimum length for each answer: one full 8 ½ x 11 page)
1. Explain completely the cause of the seasons on earth.
2. Discuss the three basic types of maps. Include in your discussion how they are constructed and of what value they can be the geographers.
3. Explain completely the cause of the monsoon. What are its effects?
4. Discuss the importance of comprehending geologic time. Provide a descriptive chronology of the more important events in earth’s history.
5. Discuss completely the four types of lithospheric plate boundaries. Describe the type of landforms associated with each.
Explanation / Answer
1. The seasons are caused by the tilt of the Earth's rotational axis away or toward the sun as it travels through its year-long path around the sun.
The Earth has a tilt of 23.5 degrees relative to the "ecliptic plane" (the imaginary surface formed by it's almost-cicular path around the sun). The tilt toward the sun is maximized during Northern Hemisphere summer in late June (the "summer solstice"). At this time, the amount of sunlight reaching the Northern Hemisphere is at a maximum.
In late December, on the date of the "winter solstice", the Earth's tilt away from the sun is maximized, leading to a minimum of sunlight reaching the Northern Hemisphere. The seasons, of course, are reversed in the Southern Hemisphere.
During the winter, cold air masses build up over North America, Europe, and Asia, due to the low intensity of sunlight. The oceanic air masses are much less affected by the seasons because circulations in the upper ocean replenish warm surface water if it has been cooled.
The strong temperature contrast between the cold air masses over land and the relatively warmer air masses over the ocean lead to extratropical (non-tropical) cyclone formation (low pressure). These storms are thus much more frequent and intense in the winter than in the summer.
2.
Maps of the world or large areas are often either 'political' or 'physical'. The most important purpose of the political map is to show territorial borders; the purpose of the physical is to show features of geography such as mountains, soil type or land use including infrastructure such as roads, railroads and buildings. Topographic maps show elevations and relief with contour lines or shading. Geological maps show not only the physical surface, but characteristics of the underlying rock, fault lines, and subsurface structures. Maps that depict the surface of the Earth also use a projection, a way of translating the three-dimensional real surface of the geoid to a two-dimensional picture. Perhaps the best-known world-map projection is the Mercator projection, originally designed as a form of nautical chart. Aeroplane pilots use aeronautical charts based on a Lambert conformal conic projection, in which a cone is laid over the section of the earth to be mapped. The cone intersects the sphere (the earth) at one or two parallels which are chosen as standard lines. This allows the pilots to plot a great-circle route approximation on a flat, two-dimensional chart.
Azimuthal or Gnomonic map projections are often used in planning air routes due to their ability to represent great circles as straight lines.
3. The monsoon, which is essentially the seasonal reversal in wind direction, causes most of the rainfall received in India and some other parts of the world. The primary cause of monsoons is the difference between annual temperature trends over land and sea. The apparent position of the Sun with reference to the Earth oscillates from the Tropic of Cancer to the Tropic of Capricorn. Thus the low pressure region created by solar heating also changes latitude. The northeast and southeast trade winds converge in this low pressure zone, which is also known as the Intertropical Convergence Zone or ITCZ. This low pressure regions sees continuous rise of moist wind from the sea surface to the upper layers of the atmosphere, where the cooling means the air can no longer hold so much moisture resulting in precipitation. The rainy seasons of East Asia, sub-Saharan Africa, Australia and the southern parts of North America coincide with the shift of ITCZ towards these regions.
4. Geologic Time Scale gives us a perspective we couldn’t have if we only considered the world in the scale of Human History. Paleontologists are still debating the length of time the human species has lived on Earth, but it may be something like one million years. And a human lifetime averages 7o years or so. But the geologic records tells us that Earth is about 4.6 billion years old. It coalesced out of planetesimals (asteroids), it gained a moon, its interior differentiated and developed distinct layers and a core, and started generating a magnetic field and global plate tectonics, it developed oceans and an atmosphere, and incubated life. We can look at evidence in the rocks and see Deep Time.
130,000 Anatomically modern humans evolve. Seventy thousand years later, their descendents create cave paintings — early expressions of consciousness.
4 million In Africa, an early hominid, affectionately named "Lucy" by scientists, lives. The ice ages begin, and many large mammals go extinct.
65 million A massive asteroid hits the Yucatan Peninsula, and ammonites and non-avian dinosaurs go extinct. Birds and mammals are among the survivors.
130 million As the continents drift toward their present positions, the earliest flowers evolve, and dinosaurs dominate the landscape. In the sea, bony fish diversify.
225 million Dinosaurs and mammals evolve. Pangea has begun to break apart.
248 million Over 90% of marine life and 70% of terrestrial life go extinct during the Earth's largest mass extinction. Ammonites are among the survivors.
250 million The supercontinent called Pangea forms. Conifer-like forests, reptiles, and synapsids (the ancestors of mammals) are common.
360 million Four-limbed vertebrates move onto the land as seed plants and large forests appear. The Earth's oceans support vast reef systems.
420 million Land plants evolve, drastically changing Earth's landscape and creating new habitats.
450 million Arthropods move onto the land. Their descendants evolve into scorpions, spiders, mites, and millipedes.
500 million Fish-like vertebrates evolve. Invertebrates, such as trilobites, crinoids, brachiopids, and cephalopods, are common in the oceans.
555 million Multi-cellular marine organisms are common. The diverse assortment of life includes bizarre-looking animals like Wiwaxia.
3.5 billion Unicellular life evolves. Photosynthetic bacteria begin to release oxygen into the atmosphere.
3.8 billion Replicating molecules (the precursors of DNA) form.
4.6 billion The Earth forms and is bombarded by meteorites and comets.
5.
There are three kinds of plate tectonic boundaries: divergent, convergent, and transform plate boundaries.
divergent boundary occurs when two tectonic plates move away from each other. Along these boundaries, lava spews from long fissures and geysers spurt superheated water. Frequent earthquakes strike along the rift. Beneath the rift, magma—molten rock—rises from the mantle. It oozes up into the gap and hardens into solid rock, forming new crust on the torn edges of the plates. Magma from the mantle solidifies into basalt, a dark, dense rock that underlies the ocean floor. Thus at divergent boundaries, oceanic crust, made of basalt, is created.
When two plates come together, it is known as a convergent boundary. The impact of the two colliding plates buckles the edge of one or both plates up into a rugged mountain range, and sometimes bends the other down into a deep seafloor trench. A chain of volcanoes often forms parallel to the boundary, to the mountain range, and to the trench. Powerful earthquakes shake a wide area on both sides of the boundary.
If one of the colliding plates is topped with oceanic crust, it is forced down into the mantle where it begins to melt. Magma rises into and through the other plate, solidifying into new crust. Magma formed from melting plates solidifies into granite, a light colored, low-density rock that makes up the continents. Thus at convergent boundaries, continental crust, made of granite, is created, and oceanic crust is destroyed.
Two plates sliding past each other forms a transform plate boundary. Natural or human-made structures that cross a transform boundary are offset—split into pieces and carried in opposite directions. Rocks that line the boundary are pulverized as the plates grind along, creating a linear fault valley or undersea canyon. As the plates alternately jam and jump against each other, earthquakes rattle through a wide boundary zone. In contrast to convergent and divergent boundaries, no magma is formed. Thus, crust is cracked and broken at transform margins, but is not created or destroyed.
Hot spots - not a plate boundary, but you'll get a volcanic island chain, like the Hawaiian Islands and Hawaiian-Emperor Seamount Range
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