Dynamics of population growth are mortality, fertility and aging society. Mortality rate is now declining due to the invention of agricultural breakthroughs like antibiotics, pesticides and vaccines. Because of the decline of mortality rate, there are lowered death rates. Fertility rate, on the other hand, is also declining worldwide especially in the developed countries because priorities of women are more on their careers and others. They also tend to marry later in life, use contraceptives and abortion to lessen or prevent births.Regulation of population growth is affected by density dependent and density independent factors.
Human activities greatly affects the ecosystem and biosphere. Example of it is the controversial global warming or climate change. It is due to the burning of coals, oil and others. Water pollution is also brought about by human activities such as excavation and construction. Ecosystem is a community of organisms living together in a particular environment in which they interact. Population in an ecosystem is essential because it is what composed the ecosystem.
Its growth is also essential depending on the situation of the ecosystem, but still very important. There are several factors that affects the dynamics of population. One of the very obvious is the decline of mortality rate. Mortality rate is declining due to agricultural revolution wherein antibiotics, vaccines, pesticides, and other life-lenghtening agents are invented (Population Dynamics, 2007). These contributes greatly to the increase in life expectancy worldwide.
Due to dramatic decline in the mortality rate, the world population had more than doubled in 30 to 65 years.And still, the population are exepected to increase due to the majority of the population is on the child-bearing stage. According to recent estimates, population will continue to increase by 1. 3 percent per year (Population Dynamics, 2007).
On the contrary, dynamics in population growth is also affected by the decline of fertility rate of women worldwide. Total fertility rate is defined by demographers as the average number of children a woman can bear. The current worldwide fertility rate is estimated to be 2. 7 per woman (Population Dynamics, 2007).
Fertility rate in developing countries are much higher than in developed countries due to the the lifestyle of women. Women in developed countries are concerned with their careers, they tend to marry later in life, use contraception and abortion to delay or prevent childbearing (The Habitable Planet, 2008). Another demographic dynamics that affects the population is the aging society. Due to decline in mortality rate, people are living longer; and due to decline in fertility rate, people are having fewer children.As a result of this, population is concentrated on the age group of 65 and above.
Population growth is being regulated in many ways. Regulation of population growth in the community has been divided into two factors; density dependent factors and density independent factors. Density dependent factors arises when the population competes to a limited resources. This includes many categories. These categories are as follows: intraspecific competition, interspecific competition, reproductive competition, migration, predation and parasitism (Kimball, 2003).Intraspecific competition involves competition among same species for a limited resources like food.
Food become limited as the population grow into a maximum size which, therefore, will lead to a competition and eventually will cause increase in death rate until food become sustainable. Interspecific competition is when two or more species share or compete for an overlapping ecological niche. Reproductive competition is when there is a decline in birth rates which leads to reduced population growth. Social conventions and birth control techniques are the factors that affect reproduction competition.Migration is a favorable factor in regulating population growth.
Upon observation, people tend to migrate to other places due to limited resources provided by the niche. This may also hinder competitions, intraspecific, as well as, interspecific. Increase in population size means increase in number of preys for the predators. There are more chances that preys will be overwhelmed by the predators.
However, there will also be an increase in the number of predators, in cases of animals, due to more interaction among them (Population Regulation in an Ecosystem, 2008).Parasites are able to pass from host to host as the population increases. Due to this occurrence, there will be epidemics that will cause a lot of casualties. Density independent factors are characterized by natural disasters like typhoon, earthquake, tidal waves, etc.
With natural calamities, population decreases until there is a sustainable number. When a catatrophy strikes especially in an island wherein there is a high occurence of calamity and fewer population, extinction is more likely to occur. Human activities greatly affects the ecosystem and the biosphere.The very controversial climate change or global warming is one effect caused by human activities.
Human activities like burning of coal, oil and natural gas, as well as, deforestation, agricultural and industrial practices all contributes to the global warming. Climate change impact is now affecting biological and physical systems of the planet. Example of the impact is the stressed coral reefs because of the rapid ocean warming. Coral bleaching in the Carribean and the Pacific oceans is also correlated to the rising temperature of the ocean.Insects, animals and plants are very much affected by the global warming.
Their natural habitat as well as their natural ways are affected. There are shifts in range, alteration in migration, hibernation, breeding cycle, physical structure and behavior of the plants, insects and plants. (The Habitable Planet, 2008) . Another effect of human activities to the ecosystem and biosphere is water pollution. Water becomes polluted because of wide range of pollutants like human wastes, inorganic and organic contaminants, and others.Industrial facilities, mining and agricultural activities are the major contributors of water pollution.
Activities like excavation and construction pollute tributaries due to erosion. Sediments from erosion cause clouding of water that leads to the hindrance of sunlight from passing through the surface of the water. Photosynthesis brought about by the sunlight is needed by fish and other aquatic organisms. Productivity is severely affected by this occurrence Habitable Planet, 2008).
