Population Growth, Biodiversity Issue, and Nutrients Found In Biogeochemical Cycles

Task 9: Human Population Growth

Carrying capacity refers to the maximum number of the population of species including humans among others that an ecosystem can support without the depletion of the available resources and services of the ecosystem like food, habitat, water, human activities, natural disasters, weather, and temperature among others Population and carrying capacity helps in understanding exponential growth and logistic growth (restricted growth). As such, this paper gives more insight on factors limiting exponential growth of populations, factors leading to logistic growth and comparison between human and natural populations.

Every kind of ecosystem has potential number of population it can hold and sustain at any given time. Owing to the nature of ecosystem, the carrying capacity of an ecosystem depends on three major factors: the amount of resources available in a particular ecosystem, the size of population and the amount of resources each member of the ecosystem consumes (Grebner, Bettinger and Siry, 2012). The human population tends to oscillate naturally around certain level of its carrying capacity over time. Density-dependent factors limiting exponential growth are factors depending on population size including diseases, births, deaths, immigration, demographics and emigration among others predict the future population size. First, diseases influence the size of the population by reducing survival and reproduction rates of human. In most cases, diseases tend to influence the size of the population with an increasing number of human population up to a certain limit (carrying capacity) above which the size tend to reduce. That is, the diseases spread widely in dense population than scarce population. Secondly, demographics show the statistical nature of the population including gender, age structure, income and education. Therefore, a population with more young people and gender balance increases the exponential growth up to a certain level above which it alternates.

Density independent factors limiting growth include, food, environmental pollution, natural calamities, and extreme weather events among others usually human orchestrate the factors (Toole and Toole, 2004). First, natural disasters such as floods continue to ravage the human population regardless of the number of people living in that particular area. Secondly, extreme weather events such as extreme temperatures due to global warming causes skin cancer. Owing to the nature of cancer, the population of a particular place will drastically decrease due to reduction in survival and reproductive rates. However, the human knowledge about various diseases and varied treatment methods increases the carrying capacity for the human population. Thirdly, the amount of food in a particular area determines the population exponential growth. That is, food directly affects the capacity of humans to grow, survive and reproduce, thereby reducing the level of fecundity.

Natural population responds to limiting factors through control of births rates, sustainable health care and control of emigration and immigration (Toole and Toole, 2004). On the other hand, human population responds to limiting factors through the development of agriculture and development of medicine to prevent diseases. There are varied factors influencing growth of human population including, famine, disease, wars, and birth control among other environmental challenges. Owing to the human population, its response to limiting factors is different from the response of natural population because it involves environmental factors that are difficult to reverse. The world population will continue to increase substantially over time before the limiting factors take effect because industrialization which has enhanced sufficient food to sustain the current population.

 

A graph of human population over time (exponential population growth).

 

 

 

 

 

Graph of Population Numbers as Population Reaches Its Carrying Capacity (“K” is The Concept of Carrying Capacity)

In conclusion, the nature of human population is something hurting to my heart because human population will plummet in the future and human species could be no more. The current number of the population is suppressing the resources available; still the prediction of scientist about adverse environmental effects will ravage the existing population.

Task 10: Biodiversity Issues

Biodiversity (biological diversity) refers to variation in different forms of life found on earth including plants, animals, microorganisms, ecosystem, genetic, species and, cultural diversity in relation to the environment (Alonso, 2008). Owing to the nature of biodiversity, all species and environment depend on biodiversity for survival and growth. Therefore, this paper gives more insight on the importance of biodiversity, implications of the loss of biodiversity and varied aspects of biodiversity.

Biodiversity has varied significance to human species including economic importance and medicinal importance and social benefits among others (Maclaurin and Sterelny, 2008).  First, biodiversity is a foundation for human health because of manufacture of pharmaceutical drugs and medical research. At the same time, some species of animals and plants helps and support in dietary health. For example, species like bears possess important medicinal resources for traditional and modern medicine in the treatment of cardio-vascular disorders, renal diseases, and renal diseases among others. However, loss of biodiversity because of human activities would lead to loss of lives due to insufficient and improper medications for various diseases.

Secondly, biodiversity is important in enhancing recreation and tourism. For instance, private bodies and governments have developed and protected national animal parks to give people sense of satisfaction in knowing the existence of various animals. As a result, such government is able to collect revenue from domesticating wildlife. However, the loss of biodiversity can result to loss of revenue for the government. Thirdly, vegetations help in recycling moisture into the atmosphere, a critical element in attracting rainfall in the process of hydrological cycle (Alonso, 2008). At the same time, vegetations and animals maintains constant concentrations of various gases in the atmosphere through the process of photosynthesis and respiration. However, destruction of vegetations pose challenges to the environment including, global warming, soil erosion, floods, extinction of some animal species among other catastrophic effects.

Aspects of biodiversity include species diversity, genetic diversity and ecosystem diversity among others. First, species diversity refers to nature of variation among various species at a particular region. That is, different types of species exist at taxonomic units including insects, crabs, worms, corals and, lampreys among other invertebrates make up to 99% of all animal species, whereas humans, fish, crocodile, frogs and birds among other vertebrates make up to 1% of animal population. Similarly, variation of species exists among various plants in different regions.

Genetic diversity refers to singular variety of genes within a species in a particular population (Alonso, 2008). In other words, in each population of different species, each species depict distinct genetic composition. Therefore, it is important to conserve each species to maintain the variety in genetic diversity. In most cases, parents pass these genes from parents to offspring and it determines genetic and phenotypic characteristic of every organism. Ecosystem diversity refers to variations in the nature of the ecosystem that provides food and shelter to different organisms. For example, some species live in forests, ponds, rivers, lakes and, nests among others, which provide habitat for various animals (Maclaurin and Sterelny, 2008). There is a relationship among species diversity, ecosystem diversity and genetic diversity because species depend on ecosystem diversity for habitat, while genetic diversity helps species to adapt to various environmental changes.

In conclusion, biodiversity anchors and sustains the efficiency of all life forms in the ecosystem. That is, species diversity promotes productivity of distinct species, genetic diversity leads to tolerance to survive in different environmental conditions, and ecosystem diversity offers shelter and food to different organisms at different levels.

Task 11: Nutrients Found in Biogeochemical Cycles

Nutrients are essential substances that plants require for growth and development (Cheworth, 2008). For instance, plants require absorbable units including, sulfur, carbon, nitrogen and phosphorous among others (macronutrients), and, chlorine, manganese, iron, and boron among others (micronutrients). However, plant requires these nutrients in different amounts. That is, macronutrients are essential substances plants and animals require in large amounts, whereas micronutrients are essential substances plants and animals require in a small amount (Chesworth, 2008). Plants usually obtain these elements mainly from the global biogeochemical cycles. Therefore, this paper explores on global biogeochemical cycles, specifically nitrogen cycle in relation to macronutrients and micronutrients.

There are five major global biogeochemical cycles categorized into hydrologic cycles, atmospheric cycles (gaseous cycle) and sedimentary cycles (Todds and Whiles, 2010). First, atmospheric cycles include nitrogen cycle and carbon cycle. The atmospheric cycles converts atmospheric gases into absorbable units by plants. For instance, nitrogen cycle converts nitrogen gas into nitrates, which plants require for growth. Secondly, sedimentary cycle involves phosphorous cycle and sulfur cycle, in which phosphorous and sulfur combines with other elements in the process of weathering, soil erosion, and deposition of minerals such as iron and nickel, which plants require in small proportions. Thirdly, hydrologic cycle involves hydrological cycle in varied processes including evaporation, transpiration, precipitation, infiltration, condensation, runoff and percolation among others. Owing to such process, plants obtain moisture and other dissolved elements in the runoff such as chlorine and sulfur (micronutrients).

Nitrogen cycle involves fixation of nitrogen gas into units that plants can absorb like ammonium ions, urea and, nitrates ions in the soil. Nitrogen gas exists naturally in the atmosphere, biosphere, and lithosphere in the form of air as the main reservoir, with approximation of 79% of total gas composition in the air (Todds and Whiles, 2010).  However, in the hydrosphere nitrogen gas exists in the form of dissolved ammonia gas. Owing to the fact that nitrogen gas has strong bonds between its molecules, plants and human converts the nitrogen gas into the absorbable units by plants through the process of fixation. The major processes involved in the nitrogen cycle include nitrogen fixation, ammonia fixation, nitrification and, denitrification. First, nitrogen fixation involves nitrogen-fixing bacteria (Rhizobium) which converts nitrogen gas into ammonia gas for assimilation by plants. At the same time, lightning dissociates the bond in nitrogen gas to combine with water thus forming nitrates and ammonia for assimilation by plants.

Secondly, nitrogen proceeds immediately after fixation of nitrogen gas. In other words, the bacteria nitrosomonas converts the ammonia gas into nitrites, and then later converted to nitrates by the bacteria known as Nitrobacter. Thirdly, ammonification is the process by which bacteria, converts nitrogen nutrients in decomposing plants and animals into ammonia gas and ammonium ions, which plants require in large quantity. At the same time, plant uptake these nutrients in the process of assimilation. Finally, denitrification involves the process by which denitrifying bacteria (Pseudomonas) convert ammonium ion and ammonia into nitrogen gas, which escapes back into the atmosphere, and the cycle continues. In summary, nitrogen cycle has helped in development of industries manufacturing not only nitrogenous fertilizers but also phosphorous fertilizers.

 

Flow Diagram Illustrating Nitrogen Cycle

In conclusion, global biogeochemical cycling has improved productivity of both aquatic and terrestrial ecosystem. Phosphorous cycle helps plants and animals to obtain phosphorous mineral (macronutrient), nitrogen cycle helps plants to obtain ammonium ion (macronutrient), and sulfur cycle helps in sulfur minerals (micronutrient). Hydrological cycle is fundamental to all plants and animals in constant supply of water.

References

Alonso, A. (2008). Biodiversity: Connecting with the Tapestry of Life. DIANE Publishing.

Chesworth, W. (2008). Encyclopedia of soil science. Dordrecht, Netherlands: Springer.

Cobb, A. B. (2006). Looking at the interdependence of plants, animals, and the environment with graphic organizers. New York: Rosen Pub. Group.

Dodds, W. K., & Whiles, M. R. (2010). Freshwater ecology: Concepts and environmental applications of limnology. Amsterdam: Elsevier/Academic Press

Grebner, L.D., Bettinger, P. and Siry, P.A. (2012). Introduction to Forestry and Natural Resources. Academic Press. Print.

Maclaurin, J., & Sterelny, K. (2008). What is biodiversity?. Chicago: University of Chicago Press.

Toole, G., & Toole, S. (2004). Essential A2 biology for OCR. Cheltenham: Nelson Thornes.

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