Introduction to Environmental Geoscience
Due 2 September 2008
Late homework will cost 15 points per week or part of a week it is late.
Has your family contributed to global population growth?
Please complete the following work to determine if your family has contributed to global population growth.
We have all heard the statement "Think globally, act locally." Let's apply it to our own families. Take a piece of paper and draw a large square somewhat like the one in the image below. Then lightly draw three horizontal lines on which you will enter symbols for your grandparents on the top line, symbols for their children on the middle line, and symbols for their grandchildren on the bottom line.
Enter the following symbols:
In writing out this assignment, I soon realized it could get complicated. Everyone denoted by a closed circle should have some of the DNA of the grandparents (related by blood was the old phrase). Everyone denoted by an open circle should not have some of the DNA of the grandparents (for example, daughters-in-law of the grandparents). But, what about adopted children and step children? Theoretically, everyone on the third line should have some of the DNA of the grandparents on the first line. To keep it simple, treat adopted children the same as all other children. But don't include step children unless they are blood relatives of the grandparents.
Here is a diagram of a hypothetical family. If it were your's, you would be one of the children on the left on the third line because these children (you and your brothers and/or sisters) have one parent from each of the four grandparents. They have no parent with an open circle. Your cousins are the other children on the third line. Your aunts and uncles are on the second line. Notice I drew the diagram with one person on the second line with two spouses. This indicates that person married twice, one marriage produced one child, one produced two children. Also notice some children never married.
This diagram has 10 open circles and 16 closed circles. The ratio is 1.6 for the two generations. The ratio for the first generation is 8/4=2. The ratio for the second generation is 8/14=0.57. Thus the first generation produced two children per person of that generation, increasing the world's population. Each person in the second generation produced 0.57 children on average, reducing population. This is fairly typical, many families now have fewer children than their parents had.
Revised on: 20 August, 2008