Photosynthesis and Soil Forming Factors - Assignment Example

Final Examination of the of the Final Examination Question Discuss your understanding on how photosynthesis has made the earth atmosphere unique in the solar system. What effects would decreasing levels of photosynthesis have on human society over time, and what could we do to stabilize photosynthesis over the long-term? Photosynthesis is a process employed by autotrophs to synthesize carbohydrates from sunlight, carbon dioxide and water. Oxygen is released as a waste product, in this process. In addition to maintaining the level of oxygen in the atmosphere, this process is also responsible for directly or indirectly providing energy to all the living organisms on earth. Hence one could say that, photosynthesis is one of the most important metabolic activities (Team, 2009). A decrease in the level of photosynthesis, results in an increase in carbon dioxide and a reduction of oxygen, in the air. The increase of carbon dioxide results increases global warming, which raises the average temperature of the earth. The result of global warming would be the melting of the polar icecaps and glaciers, resulting in an increase of sea levels, and the submerging of low lying areas, the increased spread of pathogens at warmer temperatures, and an increase in hurricanes. Furthermore, there would be a decrease in the production of food, which would pose a major problem, because of the ever increasing human population (Simmons). Consequently, the existence of humans is dependent on photosynthesis. To stabilize the levels of photosynthesis in the long term, deforestation has to be prevented and ecologically constructive activities like afforestation have to be undertaken on a large scale. Question 2. Briefly describe the five principal soil-forming factors. Soil formation can be associated with five principal factors, which are: 1.Parent material: This is the material that gets transformed into soil. In general it includes bedrock, organic materials, volcanic rocks, and materials that slide down a slope. 2.Topography: The location of the soil, determines what transformations it undergoes in the process of soil formation. For example, soil present in the bottom of a hill undergoes more erosion than soil in the top areas, and soil on the hill side that is more exposed to the afternoon sun is drier. 3.Climate: Dampness and warmth are essential in chemical leeching, which forms the soil. There is no adequate rain in deserts, and often there is no soil, as a consequence. On the other hand, in the tropics, the climate is warm with plenty of rainfall and the process of soil formation is fast. 4.Life forms: The dead remains of plants and animals living in and on the soil, are decomposed by microorganisms , and become humus that enhances the soil profile. 5.Time: This is the most important factor, as all the above factors act on the materials over time , in order to transform them into soil (The Five Soil Forming Factors). Question 3. Discuss the field capacity of a soil and why does it vary from place to place. Why would this be important to human society? Compare the soil characteristics of at least 2 places with different environments. Field capacity can be defined as the amount of moisture retained by the soil, after the excess water has been drained by gravity. Thus, it indicates the absorbing capacity of a given soil. It is important to human society as it serves as a gauge to determine if a piece of land can support a specific building and also in determining the types of crops that can be grown on it (Tatum, 2010). It varies from place to place on account of the various components that make up the soil. For instance, water is more adhesive to finer clay particles rather than coarse sand particles. Moreover, the pores between coarse particles are larger; therefore, water seeps through, and the result is a decrease in the field capacity. In areas with more sand composition in the soil, the field capacity is low in comparison to regions with more clay composition in the soil. Question 4. How is a mineral different from a rock (provide the scientific definition of each to start)? A mineral is an inorganic solid, having definite chemical composition and physical properties, and occurring in nature. It generally consists of a single element like gold (Au) or Silver (Ag). Sometimes it can also be a mixture of different elements. On the other hand, a rock is a hard solid formed by the aggregation of minerals, and has no specific physical composition and properties (Rocks and Minerals). Question 5. Discuss the difference between porosity and permeability (provide the scientific definition of each to start) and how they affect their development and use of underground water supplies. Porosity is defined as the ratio of volume of pores (openings) to the total volume of the material. Permeability is the measure of the ability of a material to allow the flow of a fluid through it (Porosity and Permeability, 2010). Porosity and permeability are interrelated; and soils, such as sand, which have high porosity are highly permeable, whereas clay, despite being porous has smaller pores and hence lower permeability. Soils that are highly permeable allow water to seep through to the water table, thereby replenishing it. On the other hand, soils where the porosity is high and permeability is low, water evaporates, before it can seep through. Question 6.Why did the scientific community reject Alfred Wegener’s continental drift hypothesis? How did society view his hypothesis? Explain the differences between Wegener’s view and that of ordinary society. Alfred Wegener’s theory of continental drift theory, states that the continents had moved over a period of time. Furthermore, he had noticed that most of the continents were grooved, as if they would fit together like the pieces of a jigsaw puzzle. He attributed this drifting phenomenon to the centrifugal forces generated by the rotation of the earth (Alfred Wegener (1880 – 1930)). This theory was rejected by the scientific community, as the actual forces generated by the rotation of the earth were calculated, and were deemed insufficient to cause the movement of the continents. It was held by the scientific community that the crust was sufficiently rigid, to prevent the continents from drifting apart (Alfred Wegener (1880 – 1930)). Question 7. Give three examples of how volcanoes have influenced civilization. Volcanoes have long influenced human resources, culture, and civilizations. Mt. Vesuvius, located in Italy, erupted in AD 79 destroying the cities of Pompeii and Herculaneum. Moreover, the course of the river Sarno was altered and the nearby beach was raised with the result that Pompeii lost its adjacency to a river or sea. Japan has been witness to the periodic destruction of villages and their subsequent reconstruction by redoubtable Japanese. It is largely believed that the Minoan civilization was destroyed by eruptions. However, the fall of the Minoans resulted in the rise of the Mycenaean culture that found favor with Homer and Schliemann. Question 8. What is the difference between the focus of an earthquake and the epicenter of an earthquake? The focus is the point, deep below the earth’s surface from whence an earthquake originates. When the focus is deep below the ground, the impact of the earthquake will be less, as the seismic waves have to traverse a greater distance. The point on the surface of the earth directly above the focus, is known as the epicenter. The maximum intensity of the earthquake will be felt here, and from the seismic waves radially spread out from the epicenter with decreasing intensity (Earthquakes). Question 9. Give three examples of human societies that have been impacted by landslides and mudslides, either continually or catastrophically. Landslides and mudslides constitute a serious problem for the people living in areas with large hills and mountains. These have affected almost every state in the United States. For instance, the 1994 Northridge earthquake caused many landslides. Cities like Pittsburgh and Cincinnati provide examples of urbanized areas with frequent landslides (Landslides and mudslides). Question 10. In what ways can moisture expedite mass wasting (describe processes)? Mass wasting is the downward movement of soil and regolith on a hill due to gravitational forces. Moisture plays a major role in all types of mass wasting. The downslope migration of talus is promoted by freezing and thawing of water in falls. In the context of slides, rainwater increases the weight of the over laden slopes and in general causes landslides. With respect to flows, water acts as the primary catalyst and combines forces with gravity. The outcome is movement of the surface. Finally, in the creep phenomenon, water once again assumes great significance. The alternating freezing and thawing produces wetness and dryness. This causes creep and this effect is more pronounced on slopes that are saturated with water. Question 11. Give some examples of what is happening to sea ice and glacial ice. Why is this occurring? How are humans impacting the situation and how is what is happening influencing humans? The average temperature of the earth’s surface has risen considerably over the past century. The effect is profoundly visible on the sea and glacial ice of the arctic region, and is termed as arctic shrinkage. The sea ice and the glacial ice are continually retreating, and as a result, a rise in sea levels has been occurring. Humans contribute to global warming by industrialization, use of aerosols, and deforestation, which release greenhouse gases into the air. These gases produce the global warming effect. As a result of increase in sea level, the low lying areas and islands are at risk of inundation, with a resulting loss of property and life, for the people of these areas. Question 12. Explain the formation and characteristics of a tsunami. Tsunamis occur usually due to an earthquake in the sea that triggers the waves, or less frequently due to meteorite falls or landslides. There are 4 stages in the formation of a tsunami. 1. Initiation: An Earthquake, causes a tremor and as a result, the sea floor is uplifted and dropped causing the water column above it to vibrate vertically. 2. Split: After a few minutes of the earthquake, the initial tsunami is split into two tsunamis, one traveling towards the deep sea, while the other travels towards the shore. The height of the split tsunamis above the sea level is about half the initial tsunami 3. Amplification: As a tsunami reaches a shore owing to the lesser depth of the water, the tsunami wave undergoes an increase in amplitude and a decrease in wavelength. This phase is known as amplification. 4. Runup: This is the height of the water above the sea level, as observed from the shore. Most Tsunamis are fast moving waves with a lot of energy, rather than huge vertical waves. Characteristics of tsunami: A tsunami is a wave and hence has the following characteristics. Wave length: Distance between two consecutive crests or two consecutive troughs of the wave. Wave height: Distance between the trough and the crest of the wave. Amplitude: The height of the wave above the stationary water line. Frequency: The number of waves passing through a given point per unit time. Velocity: The speed at which the tsunami wave propagates (Tsunamis). Question 13. Describe the paths of water through the hydrologic cycle. Explain the processes and the energy gains and losses involved in the changes of water between its 3 states. From a practical view, we are often most concerned with what water does when it reaches the earth, both on the surface and in the sub-surface. Explain the relationship between the saturated zone, the water table, a ground water well and the cone of depression, all within the sub-surface. Water covers three-fourths of the surface of the earth. It is also present as underground water and water vapor in the atmosphere. Water from the earth’s surface evaporates and enters the atmosphere. This is in turn, is returned to the surface of the earth in the form of precipitation. This precipitated water flows through the surface of the earth creating rivers, streams, and wetlands, which recharge the groundwater aquifers before merging with the sea (Natural Processes of Ground Water and Surface Water Interaction, 2008). The transformation of liquid water into water vapor is termed as evaporation. This requires a high amount of energy, known as latent heat of evaporation. About 600 calories of heat is required to convert a gram of water to water vapor. Condensation constitutes the transformation of water vapor into a liquid state. When this occurs, the energy required for evaporation, namely 600 calories per gram is released. When water changes to ice, energy known as latent heat of freezing is released into the environment. This is about 80 cal per gram. When ice transforms into water, it absorbs an amount of energy that is equal to the latent heat of freezing (Natural Processes of Ground Water and Surface Water Interaction, 2008). Most of the soil that covers the earth is porous with voids and is permeable. Hence water beneath the land surface occurs in these spaces, this is commonly known as subsurface water. It occurs in two different zones, one that contains both water and air in the voids, known as the unsaturated region. The other region contains only water in the pores and is known as saturated region. The water available in the saturated region feeds water to wells and springs (Natural Processes of Ground Water and Surface Water Interaction, 2008). The water table is the actual boundary between the saturated and unsaturated regions. Hence the water that can be extracted is below the water table. Technically the water table is the level at which the hydraulic pressure equals the atmospheric pressure. An aquifer is a geological formation that can feed water to a well or a spring. The movement of water from an aquifer into a well forms a depression around its surface. This is shaped like a funnel and is termed the cone of depression. All the ground water flows into the well via this cone of depression (Natural Processes of Ground Water and Surface Water Interaction, 2008). Question 14. Describe the general sequence of events in continental drift since the time of 5 separate continents 450 million years ago. What is the difference between the older continental drift hypothesis by Wegener and the more recent plate tectonic theory? Plate tectonics theory explains many seemingly unrelated phenomena. Explain how the patterns of volcanoes and earthquakes related to plate tectonics. Explain several pieces of evidence that combine to make the theory of plate tectonics the one that is generally accepted. Provide and explain at least 3 types of evidence supporting the idea of sea floor spreading along the mid-ocean ridge in the Atlantic. Around 450 million years ago, there were five continents. These began to move closer to each other and finally formed the super continent Pangaea around 286 million years ago. About 208 million years ago, Pangaea broke apart into two continents- the Laurasia and the Gondwana. Around 100 million years ago, further continental drift occurred and the modern continents started to form. About 1.8 million years ago in the beginning of the Pleistocene Epoch, the modern continents reached their present positions (Timeline of World History, 2009). According to the plate tectonic theory, the earth’s outer layer is made up of several tectonic plates, which have moved relative to each other, since the formation of the earth. This differs from Wegener’s theory, due to the recognition of tectonic plates, which explain how relative motion is possible between the continents (Plate Tectonic Theory, 1998). Volcanoes and earthquakes occur chiefly in locations with geological activity of the tectonic plates. Thus, most of the volcanoes and volcanic islands occur on the edges of two tectonic plates. This is because, the magma spills out when two plates collide, and the resulting debris gradually changes into the land forms above the sea level. Earthquakes occur in regions where the tectonic plates collide with each other (Schnaubelt, 2010). An examination of the paleomagnetism and core samples from the Mid Atlantic Ridge, demonstrates the manner in which the spreading of the sea floor had caused it. New crust was added, which brought about a lateral spread of the sea floor. The newly formed material has been seen to be present on the ridge, with the older material being displaced away from the ridge. As a consequence of this process, the heat convection mechanism of the earth is promoted, which causes the tectonic plates to move across the earth. The movement, breaking up and collision of the tectonic plates is mainly aided by the spreading of the seafloor. Question15. Provide a reason why some scientists believe the Pleistocene is over and a reason why other scientists believe we are now in an interglacial stage. Some believe, for example, that since areas of pack ice and glacial ice still exist we are still in an ice age. Others, on the other hand, seeing the rapid retreat of ice and snow pack in many areas, believe that this period of glaciation has ended. So, using some other justifications, why do we see some differences in interpretation? Are there some scientific data available that can support the view of both sides? If so, provide it. Why hasn’t this controversy been solved? What impact does this division of views have on the public policies that are enacted by state, national and international bodies? During an ice age there is are periods when glaciers advance, interspersed with periods where the glaciers are in retreat. These periods can be of considerable duration, and it is difficult to determine if we are in the midst of an interglacial period. This is due to the fact that less than 10, 000 years have elapsed, since the latest interglacial period of the Pleistocene Epoch. Moreover, it is difficult to ascertain if there is a glacial period awaiting us, or if we have just emerged from such a period. For instance, in the interglacial period, the earth undergoes warming and the average surface temperature increases. Hence, the phenomenon of global warming may not have as great a significance as is being accorded to it. Hence, the cap and trade policy, which focuses on decreasing carbon emissions, may not be very effective in reducing global warming. This is the stance of the US Government. List of References Alfred Wegener (1880 – 1930). (n.d.). Retrieved June 12, 2010, from University of California Museum of Paleontology: http://www.ucmp.berkeley.edu/history/wegener.html Earthquakes. (n.d.). Retrieved June 12, 2010, from http://www.s-cool.co.uk/gcse/geography/tectonics/earthquakes.html Landslides and mudslides. (n.d.). Retrieved June 12, 2010, from http://nilesema.com/landslides.htm Natural Processes of Ground Water and Surface Water Interaction. (2008, May 2). Retrieved June 12, 2010, from USGS: http://pubs.usgs.gov/circ/circ1139/htdocs/natural_processes_of_ground.htm Plate Tectonic Theory. (1998). Retrieved June 12, 2010, from http://www.pbs.org/wgbh/aso/tryit/tectonics/intro.html Porosity and Permeability. (2010). Retrieved June 12, 2010, from enotes: http://www.enotes.com/earth-science/porosity-permeability Rocks and Minerals. (n.d.). Retrieved June 12, 2010, from Ontario Goescience Resource Network: http://www.ontariogeoscience.net/keyconceptitems/rocksandminerals.html Schnaubelt, A. (2010, March 15). Understanding Mountains and Volcanoes. Retrieved June 12, 2010, from http://geography.suite101.com/article.cfm/understanding-mountains-and-volcanoes Simmons. (n.d.). 5 Deadliest Effects of Global Warming. Retrieved June 12, 2010, from Environmental graffiti: http://www.environmentalgraffiti.com/sciencetech/5-deadliest-effects-of-global-warming/276 Tatum, M. (2010). What Is Field Capacity? Retrieved June 12, 2010, from wiseGEEK: http://www.wisegeek.com/what-is-field-capacity.htm Team, C. T. (2009, November 23). Photosynthesis. Retrieved June 12, 2010, from ORACLE ThinkQuest: http://library.thinkquest.org/3715/photo3.html The Five Soil Forming Factors. (n.d.). Retrieved June 12, 2010, from http://www.brynmawr.edu/Acads/Geo/Geo101/soil.html Timeline of World History. (2009, January 29). Retrieved June 12, 2010, from http://fajardo-acosta.com/worldlit/timeline-00.htm Tsunamis. (n.d.). Retrieved June 12, 2010, from http://earthsci.org/education/teacher/basicgeol/tsumami/tsunami.html Read More