Hydrosphere, Biosphere and Lithosphere
The hydrological cycle encompasses the continuous circulation of water, which represents the various paths through which water circulates and is transformed in the environment. From the Earth’s surface; water evaporates into the atmosphere in a gaseous state as water vapour. Consequently, the atmospheric moisture is returned to the earth’s surface through precipitation as rain or snow. The snow accumulates in mountains as ice, which melts into liquid water that moves into the soil and streams. When the rain water falls into the land surface with asphalt, it forms a runoff that flows into the rivers, lakes, and oceans. The plants absorb the water in the soil by their roots where it moves into the leaves and evaporates through the stomata via transpiration process (Frost, 2000).
Some water seeps down into the earth’s surface forming saturated zone called ground water where the top part of the saturated zone is called the water table. When a huge volume of ground water accumulates in a water-bearing rock, it forms an aquifer, which serves as a source of ground water wells. As water is drawn from wells, it lowers the water table adjacent to the well creating a cone of depression; therefore, diverting the flow of groundwater towards the well while it flows into the depression cone (Monroe, Wicander & Hazlett, 2006).
Food chains indicate the pathway of energy and nutrients within the ecosystem where the arrow shows the flow of energy from the sun to the top predator. The primary producers, particularly plants, make their own food from sunlight by photosynthesis. The primary consumers (grasshoppers) feed on plants and are later fed on by secondary consumers (rat). Besides, the secondary consumers are eaten by tertiary consumers (snake), which are then fed by quaternary consumers (hawk). Addition, the detrivores like vultures feeds on death animals while decomposers help in the decay of dead organism hence continuing the exchange of nutrients. In the study of organisms, the biologists are more concerned in the study of complex systems within each life form whereas geographers study how the landscape affects the organisms and their distribution throughout the biosphere. Biome refers to the largest ecologic units of plants and animals living in similar climatic conditions on the earth. However, zoogeographic regions refer to specific regions of distinctive fauna where they are based on the phylogenic or taxonomic relationships of animals rather than the adaptations to the specific environments. In the desert biome, the floral characteristics include cacti, mesquite, and sagebrush that are adapted in conserving water for long periods. In tundra biome, a variety of lichens and sphagnum moss are well adapted to severe subarctic climate (Hess & McKnight, 2013).
The formation of soil depends on parental material, time, as well as changes in land use that alters the content of nutrients and development of the ecosystem. The parent rock material determines the type of soil formation following its weathering and decay in order to release the organic material in the soil. In soil development on forested and sloped area, the formation of soil is affected by water erosion where water run-offs may carry away the alluvium. Contrary, a grassed flat area is more susceptible to wind erosion that may blow away the developing soil. In deserts and tundra, topography and climate may supersede the influence of parent materials in soil formation (Chesworth, 2008).
In shaping the earth’s surface, both the internal and external geologic processes including erosion, earthquakes, depletion of resources, and the impact of meteors help to alter the chemical composition of the earth, as well as the landscape. Moreover, the surface of the earth has changed over time due to a gradual movement of tectonic plates hence causing shifts in sea levels resulting to the formation of islands (Hess & McKnight, 2013).
During the early Mesozoic and the late Paleozoic years, the supercontinent Pangaea was surrounded by the panthalassic Ocean. The global ocean consisted of Tethys Ocean to the north and to the west the Pacific Ocean. After the breakup of Pangaea and the end of Tethys basin, panthalassic Ocean became the Pacific Ocean. The older continental drift theory by Wegener only demonstrated how Pangaea split to form the current seven continents. However, the recent plate tectonic theory not only illustrates the continental drift, but also explains how the tectonic plates leads to the formation of earth’s landscape such as mountains, volcanoes, as well as the occurrence of other geologic processes such as earthquakes. In the evidence o plate tectonic theory, researchers found strange features around the mid-Atlantic ridge, which showed that the ridge was seismic active. Besides, all of the earth’s oceans had similar ridge systems hence further supporting the theory of plate tectonics (Frisch, Blakey & Meschede, 2010).
The Pleistocene is a period that many endangered species went to extinction throughout the world due to fluctuations in climate. Some scientists argue that the migration of human beings led to overhunting leading to the extinction of endangered species. In addition, the fluctuations in the global temperatures marked the start of interglacial periods where ice sheets and glaciers retreated. As a result, the animals were forced to migrate to the tropics for much warmth while the few hardy species adapted the cold. Currently, the sea level has risen due to continuous melting of glaciers in the mountain due to increased global temperatures. In addition, global warming cause desertification that has resulted to reduced grazing lands for wild animals. Besides, there has been a continuous increase in pollution that destroys the natural habitats of wild animals, as well as deaths of endangered species. Both arguments of whether the present generation lives in Pleistocene or interglacial stage have merits although it is not clear what caused extinction. However, it is evident clear that we live in interglacial stage due to the current increased global temperatures. The two divisions of views may affect the policies targeting the protection of endangered species. The policies may not comprehensively cater for both views because there is limited evidence in support of either view (Schlesinger & Bernhardt, 2013).
Chesworth, W. (2008).Encyclopedia of soil science. Dordrecht, Netherlands: Springer.
Frisch, W., Blakey, R. C., &Meschede, M. (2010).Plate tectonics. Berlin: Springer.
Frost, H. (2000). The water cycle. Mankato, Minn: Pebble Books.
Hess, Darrel & McKnight Tom (2013). McKnight’s Physical Geography: A Landscape Appreciation, Eleventh Edition. Upper saddle River, NJ: Pearson Education Inc
Monroe, J. S., Wicander, R., & Hazlett, R. (2006).Physical geology: Exploring the earth; [the wrath of Hurricane Katrina ; Could you survive a Tsunami?; catastrophic earthquakes; global warming]. Belmont [u.a.: Thomson. Schlesinger, W. H., & Bernhardt, E. S. (2013).Biogeochemistry: An analysis of global change.