Graphing Human Population Growth

Graphing Human Population Growth Objectives: Complete the labeling of the graph of human population growth and use it to predict future growth. You will identify factors that affect population growth. Table 1: Human Population Growth Table 1 (continued) Time (Year) Number of People (in Billions) Time (Year) Number of People (In Billions) 1650 0.5 1974 3.9 1750 0.7 1976 4.0 1850 1.0 1980 4.4 1925 2.0 1991 5.5 1956 2.5 2000 6.0 1966 3.3 2010 6.8 1970 3.6 2021 7.8 Blue Line: known measured data. ** Red Line: best fit line continues the trend of human population growth; this will allow you to predict future human population numbers. Graphing Analysis: 1. It took 1649 years for the world population to double, going from .25 billion people to 0.50 billion people. How long did it take for the population to double for the 2nd time? 100 years A 3rd time? 50 years A 4th time? 50 years 2. Based on your graph, in what year will the population reach 8 billion? 2024 3. Based on your graph, how many years will it take for the population of 2000 to double? 50 years The Earth’s Carrying Capacity Prior to 1950, the death rate was high, which kept the numbers of humans from increasing rapidly. In the 10th Century, the agricultural revolution increased food production. The industrial revolution improved methods of transporting food and other goods. In the 20th Century, advances in medicine, sanitation, and nutrition have decreased the death rates further. These factors combined to produce the rapid growth of the human population in the 20th Century. As with any population, humans are also limited by factors such as space, amount of food, and disease. The carrying capacity is the number of individuals that a stable environment can support. Authorities disagree on the maximum number of people that the earth can support, though the numbers generally range from 8 to 10 billion. As the population approaches its limit, starvation will increase. Some countries have a much higher growth rate than others. Growth rate is the number of people born minus the number of people that die. Most countries are trying to reduce their growth rate. Zero population growth means that as many people are being born as there are dying – to achieve zero population growth, each couple would need to have no more than two children (to replace the parents). Even if this number is achieved, the population will continue to grow because the parents will still live on for decades, as their children will have children and their children have children…and so forth. The United States reached zero population growth in the 1980’s, and yet the overall population of the US still increases. Carrying Capacity Analysis 1. What factors contributed to the world’s overall population growth in the last 150 years? Advances in medicine, sanitation and nutrition and increased food production has contributed as factors of growth. 2. Why does a population not level off during the same year it reaches zero population growth? People will continue to have babies and the babies will also have babies and the parents will live on for a few decades. 3. What is carrying capacity? The average population density or population size of a species 4. If the carrying capacity of the earth was 9 billion people, when would this number be reached (according to your graph)? 9 billion at around 2035-2040 5. What will happen when the human population exceeds the earth’s carrying capacity? People will have to compete for resources, those resources will become nonexistent and then humans could potentially die off due to no resources.