In the genealogy that dominates the remainder of Genesis 11, we begin to notice that people are not living quite as long now. As a personal theory based on my own research, I would propose that the Flood - in particular the loss of the firmament - altered the environment in such a way that the lifespans of people were affected. Of course, this takes place over a period of roughly 700 years after the Flood, and we see a gradual decline in longevity to the point that by the end of Genesis, the longest-lived person is about 120 years old as opposed to the 900-year lifespans we saw before the Flood. That being said, we now want to take a look at the generations following the Flood.
The etymology of names in this lesson is courtesy of Judson Cornwall and Stelman Smith, The Exhaustive Dictionary of Bible Names (Plainfield, NJ: Bridge-Logos, 1997).