World population is constantly growing. We now have a world population of over 6 billion people. At the current rates of increase, we will probably see a world population of 12 billion within our lifetimes. Having this many people on earth has already had wide-ranging effects on the natural environment. Obviously, not all of these people are spread evenly across the planet. Some areas are more populated than others. Population density is expressed in the number of people per square kilometer.
This map of population density from 1994 still gives a good picture of the population density of the world today.
Even in areas of low population density, we have changed landscapes to suit our purposes. For example, look at the Midwestern farming states in the US. These areas were once wild grassland, but the land is now home to a very few species- corn, soybeans, and wheat. Even though this area has a relatively low population density, humans have radically altered the landscape there.
The population density of an area can have dramatic effects on its geography. Rivers can be rerouted, mountains flattened, and ground is paved over to make way for transportation. Pollution also tends to be a problem in areas with a high population density. In addition to cities as we might traditionally think of them, temporary cities can also spring up, like shantytowns on the outskirts of major cities, or refugee camps.
10: All answers are correct within the second revision of this lesson. Answers are correct, complete, and clear; all lesson requirements have been met. All answers are in complete sentences with correct grammar and spelling.
9: All answers are correct within the third revision. Answers are correct, complete, and clear; all lesson requirements have been met. All answers are in complete sentences and work is spell-checked, but may have a few grammatical errors.
8: All answers are correct after four or more revisions. Answers are correct, complete, and clear; all lesson requirements have been met. All answers are in complete sentences and work is spell-checked, but may have a few grammatical errors.
7: One or two answers are incorrect. All other answers are factually correct, complete, and clear. All lesson requirements have been met. All answers are in complete sentences and work is spell-checked, but may have a few grammatical errors.
6: Reserved for administrative use.
5: Plagiarism - purposeful or mistaken which will lower your final grade for the course (so be very careful when posting your work!); lack of effort, disrespect, or attitude (we are here to communicate with you if you don't understand something); or 9 or more errors; or lesson requirements have not been met.
Also be aware that you will have a chance to revise your work. More than 2 revisions will result in a lower grade, so read the directions carefully and make sure you meet the requirements. No lesson is complete without the approval of the instructor, and all revisions must be completed before a grade is assigned. No grade will be given for incomplete work.