Allison Frye's environmental studies class at The Gunnery, a private school in Washington, recently studied human population growth and its effects on the environment.

They considered such topics as birth rate, death rate, fertility rate, and doubling time (the time it takes for a population to double in size).

One of the reasons suggested for recent exponential population growth is the fact that people in more developed countries are, on average, living longer.

As a class, they decided to test this theory using the statistics on life expectancy available in the local cemetery.

They collected information about gender and age at death for those who died before 1900 from Judea Cemetery, just a short distance from the Gunnery campus.

They compared the resultant data to recent obituaries (those who died in 2011) to compare the life expectancies, both recent and pre-1900.

Students then created several types of graphs to display the findings, such as bar graphs, survivorship curves and population pyramids.

The results yielded the proof they were testing: life expectancy is, in fact, increasing in our local community.

The pre-1900 average age at death for males and females, respectively, was 62 and 57, while the 2011 average age at death for both males and females, respectively, was 72 and 79.