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As of July of 2007, the world population reached 6,602,224,175. Scientists predict that a century from now the world population will probably reach 10.

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Presentation on theme: "As of July of 2007, the world population reached 6,602,224,175. Scientists predict that a century from now the world population will probably reach 10."— Presentation transcript:

1 As of July of 2007, the world population reached 6,602,224,175. Scientists predict that a century from now the world population will probably reach 10 to 15 billion people. Will the world be a nice place to live in? Optimists think that the planet can accommodate a much larger population. Others, more pessimistic, predict catastrophes before ever reaching this number.

2 On a global scale, will our natural resources run out?

3 Nearly 200 years ago, Thomas Malthus had grim predictions for the future of humanity because of the burden our rising population puts on the Earth. It’s true that if everyone on the planet today adopted a North American lifestyle, natural resources would quickly be exhausted. Malthus believed that forces such as war, pestilence, famine and plague would be checks on a swelling population. It is not only consumption that is high in wealthy nations, but waste as well. Our very survival depends upon population control as well as a better management of natural resources. Think about our Consumption of fossil fuels Nature’s way of cleaning up human problems…

4 Was Malthus right? Has starvation increased? In spite of the population increase, famines have become less frequent in the past two hundred years, thanks to phenomenal agricultural yields, increasing infrastructure and global economy. The causes were all due to political problems --including civil wars-- that disorganize the economy, paralyze transportation, and prevent emergency food drops from reaching their destination. Famine is not due to a global food shortage, but rather local food shortages and lack of infrastructure. In the last few years, however, several African countries have been affected by famine. Why?

5 Is population aging a threat? With an increased lifespan and a more stable world population the proportion of older people will increase. Retirement age and retirement objectives will have to be revisited. However, people living a longer and healthier life will consider themselves "older" later in life What are some possible consequences of an “older” population?

6 The recent global population growth is not the consequence of increased birth rates... but of an unprecedented decrease in death rate. The 20 th century has resulted in victory over most famine- related and infant mortality, as well as a significant advance in public health and medicine. Over eight hundred supercentenarians have been documented in history, and this is doubtless a fraction of the number who have really lived There are an estimated 300 to 450 living supercentenarians worldwide today, with around 60 in the United States. How old is a supercentenarian? >110

7 For hundreds of thousands of years the human population was growing at a slow but steadily increasing rate. Then in less than 200 years, the world population went from 1 billion to 6 billion people. Why? Because the balance between birth and death has been broken. When birth rate equals death rate, there is a “0” population growth. When birth rate exceeds death rate, there is population growth. When death rate exceeds birth rate, there is a population decline.

8 There are more than 6 billion human beings on Earth, and counting. Every second five people are born and two people die, a net gain of three people.. The 6 billion mark was reached on October 12 1999. Where is the population growing fastest? At this rate, the world population is doubling every 40 years and would be: 12 billion in 40 years,  24 billion in 80 years,  48 billion in 120 years… However the United Nations estimate that we will only be 12 billion in 120 years.

9 When demographers study populations, they divide the world up into regions. Developed countries are those that are industrialized and have a high standard of living. Some examples of developed countries are: America, Europe, Japan and Australia. Developing countries occur where the standards of living are lower. Most are agricultural nations. Some developing countries are: India, East and Central Africa, and China. Developed countries have experienced both a decline in death rate, and a decline in the birth rate. Developing countries, on the other hand have experienced a decline in their death rate, but their birth rates haven’t fallen nearly so much. This has resulted in rapidly growing populations, poverty, and starvation in these parts of the world.

10 Why has the world's population exploded in recent years and why might it stabilize during the next century? Culturally preconceived notions of family size… In many cultures, it is beneficial to produce large families. children provide security in old age especially male children in these countries children cost little to raise The size of the developed world is growing, while developing and undeveloped are getting smaller and smaller. Remember your statistics from the normal growth patterns of populations in these places.

11 This age distribution analysis graph shows negative growth. These projections are for Japan, in the year 2050. Does this graph show positive population growth, “0” population growth, or negative population growth? Should this be the goal of every culture?

12 Right now, the world’s human population is growing at an average rate of 1.4% per year, giving it a doubling time of approximately 50 years. The rapid addition of more people has significant implications. The Earth, after all, is a finite system, and cannot sustain continued exponential growth indefinitely. The absolute maximum population the Earth can sustain at a reasonable average living standard for its inhabitants is called the carrying capacity. Every habitat, no matter how rich, contains limited supplies of important resources like food, shelter, mineral nutrients, water, and light. When a population grows rapidly, it consumes these resources at an increasing rate. The resources that limit the growth of a certain population are known as limiting resources, or factors. What are some limiting factors we deal with?

13 Human growth patterns exhibit exponential qualities. This means that in a given time, the population will double. Humans exhibit the same type of growth patterns as bacterial infections. What are some of the limiting factors for these bacterial colonies? The petri dish the bacteria are in is only half full at 11:59am. If you were one of the bacteria in the jar, at what time would you perceive crowding, or that you may be in danger of running out of space? Before you answer this question, consider the fact that at 11:55 am the bottle is only about 3% full. Would you likely recognize a space problem in the next 5 minutes?

14 On a graph, an exponential curve is often perceived as a “J” shape. This section represents the area of exponential growth. The population of rabbits doubles frequently. This area represents the carrying capacity of this particular ecosystem. This is the point where there is just enough food and other resources for the existing rabbit community. No more can be supported. What do you think happens to the graph when the population exceeds the carrying capacity?


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