Population

**__Human Popul__****__ation__**
Over the past several decades due to the successive cultural revolutions, such as agricultural revolution, human population has surged. In the graph above it accosts that human population has just entered the exponetial growth phase not yet exceeding the carrying capacity and generally showing a typical "J-shaped grwoth" It is also noticable in the graph that human population graph has fluctuated between 2000 AD due to several factors such as Agricultural revolution and Black Plague. This page is going to talk about what factors are affecting the human population and what effects do the human population cause to the environment.

Birthrate (Natality) is simply the rate of human babies. As population rises birthrate also rises, and as birthrate rises so do the human population. The typical evidence of the effect of birthrate on human population is shown in every country where it had a period of "Baby Boom" where the government actively engaged in increasing the total population amount by opening campaigns and conducting protocols. Along with the Birthrate Mortality is another key factor in deciding the population. Mortality, simply the deathrate, increases as population increases and there are several factors in affecting the mortality. The Following factors are shown below. Factors affecting Mortality (Death Rate): Emigration is simply the factors which contribute to balancing the overall human population. Emigration simply means the population which goes out and abroad to another country thus decreasing the country's total population amount. In contrast to emigration, imgration is the the amount of population entering the country which builds up to total population in the country.
 * __Factors Affecting Human Population__**
 * 1. Birthrate (Natality)**
 * 2. Mortality (Death Rate)**
 * better nutrition
 * greater access to medical care
 * improved sanitation
 * more widespread immunization
 * 3. Emigration**
 * 4. Imigration**
 * Final Human population balance: Birth rate + Imigration = Emigration + Mortality

The increase in human population on the environment has led - As human population increases, so does the consumption of water. - In the past fifty years, the per capita availability of fresh water has decreased by one third. - More than 95% of urban sewage in developing countries is discharged untreated into the nearest waterway or field. - The main contributors to water pollution are factories Factories and open mines, discarding mines discard waste water with heavy metals, toxic substances and solid waste, which are virtually impossible to purify. - Overfishing changes the balance in coastal ecosystems and decreases fish populations. Sometimes it might even lead to extinction of certain marine species. Overfishing also damages coral reefs, because it allows algae to overgrow them. waste - Ocean is "the ultimate garbage dump" because eventually all of the sewage, sediment from forest clearing, fertilizer and pesticide run-off flow into it. - Population growth results increases the demand for food production. Farmers begin to cultivate dry, hilly, nutrient-poor areas that are not very suitable for farming. Exploiting such lands makes them easily susceptible to erosion and loss of nutrients. - For example, in search for farmland in Indonesia, peasants have been planting their crops on steep slopes. As a result, almost Almost one half of Java's land is now in danger of erosion. - It is estimated that 1.2 billion hectares of land, approximately the size of Europe, U.S. and Mexico combined, have lost much of their agricultural output capability in the last 50 years. - Forest area is burned and converted into pasture, but due to poor soils, it looses its productivity in about three years. This initiates a vicious circle which results in the deforestation of large areas, mostly in tropical regions. - Deforestation is also caused by the use of wood as fuel, since 9 out of 10 African households use wood for cooking and heating. This is the reason why Ghana lost almost a third of its dense forest from 1938 to 1980. - The building of roads and the expansion of residential areas have contributed to the loss of primary forest. - The natural flora and fauna have been under constant pressure to adapt to a quickly changing environment. Since they have been unable to do so, they have been displaced from their natural ecological niche. - The constant clearing of the Amazon forest has had devastating effect on many rare tropical species. It has been estimated that 10% of the species in the region have become extinct. - The expansion of human population and agricultural expansion has caused more and more people to search for fertile lands. Moreover, due to the widespread deforestation and water pollution, now much of the animal habitat is destructed. For instance more than half of the forest since the past 500 years have been burnt and destructed which led to many extinction in certail types of animals - Habitat destruction resulted in some wild animals living and searching for food in urban area, and becoming unafriad of the humans. The typical examples includes racoons, and alligators in some parts of America searching for food. Interestingly there has been reports where goats have been using the human facillities, roads, to escape from the bear.
 * __Impact of Human population (overpopulation) on the Environmnet__ **
 * · Water supply**
 * · Water pollution**
 * · Soil degradation**
 * · Deforestation**
 * · Loss of biodiversity**
 * · Habitat destruction**

Human Our human population growth has largely followed is maintaining the J-shaped growth curve. Our J curve due to our intelligence, tool making abilities and capacity for storing energy sources, which so far enabled us to move into new habitats and increase the carrying capacity of the earth.However, we can only postpone the inevitable for so long. Sometime in the future population growth will exceed the carrying capacity of the earth, as predicted by Malthus over 200 years ago.Eventually ago.If so happens, eventually our J-shaped growth curve will begin to change into the S-shaped curve. This will be done either voluntarily or nature will do it for us. Recall that in the process of succession some organisms modify their environment so much that they can no longer live in it. If humans exceed the "self cleansing" capabilities of the earth, it is possible that we may become just another transitional community, replaced by other organisms.
 * __Conclusion__**

__**Links**__ http://dieoff.org/page57.htm 1. Factors Affecting Human Population PPT slides: http://www.gpc.edu/~ccarter/Millerlec9/sld006.htm 2. Future Human population predictor http://www.cosmosmith.com/population_predictor.htm
 * - Websites/Articles**
 * - Links/Slides**