Q1-Explain why -the flow of energy through the biosphere depends on the cycling of nutrients? and – the cycling of nutrients depends on gravity.
1a- Biosphere and nutrients
Soil is at the base of the biosphere. Soil is living, maturing entity and life exists within the soil in various forms. Natural vegetation is the most obvious proof of the earth’s life layer. It has various nutrients which are utilized by plants for photosynthesis. The most essential start of energy flow in the biosphere is photosynthesis. Photosynthesis is a process through which plants make their own food with the help of sunlight and carbon dioxide at the same time releasing oxygen. (Biosphere)
An ecosystem is a nexus between plants and animal in terms of energy. Solar energy along with inorganic nutrients is absorbed by plants and chemical energy is lost. Inorganic nutrients include phosphorous, nitrogen and iron. (McShaffrey) Energy from the sun is converted by photosynthesis green plants. Such food producing plants provide food for small larvae and other tiny life forms. In turn these are eaten by animals, which are eaten by other animals. During all this plants and animals die and decay. (Biosphere)At this stage, the last of the energy is extracted (and lost as heat) and the inorganic nutrients are returned to the soil or water to be taken up again. (McShaffrey) Therefore, this cycle of nutrients and energy flow is important for all life forms to exist in biosphere. Inorganic nutrients are either taken up by plants from atmosphere or water. For taking up nutrients from water, water cycle is necessary.
1b-Relationship of gravity with various nutrients’ cycles
Water may be absorbed by atmosphere but it returns to the land surface under the force of gravity or gravity induced pressures. Once water condenses, gravity takes over and the water is pulled to the ground. Gravity continues to function, either pulling the water underground or across the surface. Water may have nitrogen and phosphorus contents as well. So gravity isn’t just essential for water cycle. But it indirectly helps in nitrogen cycle. The third form of nitrogen-fixing bacteria is the photosynthetic cyanobacteria (blue-green algae) which are found most commonly in water. (McShaffrey) This bacterium fixes nitrogen to nitrate. Most plants take up nitrate and synthesize it to amino acids. Therefore, gravity plays an important role in both, water and nutrients cycle.
Q2- Explain why microbes are so important? List two beneficial and two harmful effects of microbes on your health and lifestyle. Write a brief description of what you think would happen to you if microbes were eliminated from the earth.
2-Benefits of microbes
Microbes are involved in cycling vital elements such as carbon and nitrogen, breaking down wastes and dead organisms into simpler substances plants can use in photosynthesis. But microbes are essential for humans as well. In recent years the uses of microbes have been discovered which are of immense importance for better utilizing the nature’s gifts. Biotechnology is often associated with the use of genetically altered microorganisms such as E. coli or yeast for the production of substances like synthetic insulin or antibiotics. Apart from medicinal importance, microbes have agricultural importance as well. Biotechnological advances in agriculture also require the help of microorganisms. Transgenic plants can increase yield, reduce vulnerability to environmental and pathogenic stresses, improve taste and appearance and produce novel plant substances. To create transgenic plants, a vector, Agrobacterium, is required to transfer genetic material into the plant host. Had there been no microbes there wouldn’t have been medicinal and agricultural advancements. (Hua)
Q3- Describe the major differences between the ecological niches of humans and cockroaches. Are these two forms of life in competition? If so, how do they manage to coexist?
3-Ecological niches of humans and cockroaches
Every organism in an ecosystem has a niche, a special role or function that they play. The cockroach plays the role of a decomposer which is an essential part of any ecosystem. Living organisms are interdependent; they need each other in order to survive. Therefore it is wrong to say that roaches and humans are in competition. To be in competition they both must fight to overcome the other. Roaches play a significant role as first tier decomposers. They shred dead and decaying organic matter into smaller pieces so that it would be eaten by recycling bacteria. Heaps of dirt would pile up if it weren’t for cockroaches to feed on dirt. It is true that they carry diseases because they eat rotten food, and thus pick up any nastiness was on the food to begin with. But most importantly they could serve as a reset button for life if there were a nuclear war, due to their very high tolerance of radiation. Cockroaches unlike humans live in really dirty and dark places because they can find food easily in them. Generally speaking, all life on this planet fills some ecological niche that cannot be filled by anything else, and if we wipe out that life, we may subvert earth’s fragile biological balance. Moreover, if humans decide to destroy all the roaches on earth it would be impossible to do so without opting fumigation for the entire planet, which would also kill humans. (Paige)
Q4- Explain how would respond to someone who says that because extinction is a natural process, we should not worry about the loss of biodiversity when species become prematurely extinct as a result of our activities.
4- Worry over extinction of various species
It is true that extinction is a natural process but extinction of specie or a life form requires hundreds and thousands of years. Till that time other life forms that previously depended on the extinct life form develop and find ways to meet their requirement from other life forms. However if rapid extinction takes place it would be problematic to cope with rapid changes. Due to certain human activities, many life forms are speeding to extinction. It is the matter of worry because the extinction rate at present is increasingly. So if it wasn’t for humans the natural rate would be such that the environment could recover from it.
Dynamics of the biosphere, n.p. n.d. web July 14, 2010 http://mac122.icu.ac.jp/gen-ed/ecosystems.html
Hua, Linda. (2010), How is microbes beneficial, n.p. web, July 14, 2010 http://w3engineers.com/lindahua/index.php/science/how-is-microbes-beneficial/
McShaffrey, D. Environmental biology – Ecosystems, Marietta College, February 3, 2006, web, July 14, 2010, http://www.marietta.edu/~biol/102/ecosystem.html#Overview
Paige, The feared, the pest, the cockroach, American Museum of Natural History, n.d. web, July 14, 2010 http://www.amnh.org/nationalcenter/youngnaturalistawards/1998/pestroach.html