Genesis 5:1b-11
In the day that God created man, he made him in God’s likeness. He created them male and female, and blessed them, and called their name “Adam,” in the day when they were created. Adam lived one hundred thirty years, and became the father of a son in his own likeness, after his image, and named him Seth. The days of Adam after he became the father of Seth were eight hundred years, and he became the father of sons and daughters. All the days that Adam lived were nine hundred thirty years, then he died.
Seth lived one hundred five years, and became the father of Enosh. Seth lived after he became the father of Enosh eight hundred seven years, and became the father of sons and daughters. All the days of Seth were nine hundred twelve years, then he died.
Enosh lived ninety years, and became the father of Kenan. Enosh lived after he became the father of Kenan, eight hundred fifteen years, and became the father of sons and daughters. All the days of Enosh were nine hundred five years, then he died.
Notice how this passage starts out from the beginning again. It is good evidence that it is a different writer and that they intend to start at the beginning again. This time, we are looking at the genealogy of Adam and Eve through Seth’s line.
The remarkable difference between genealogies today and this one, is the age of the people before they died. Adam lived 930 years! Seth, at the young age of 105, had his son Enosh and then went on to live until he was 912. These guys lived a long time. Now it makes more sense how a guy like Cain could build a whole city in a single lifetime. They must have been pretty healthy to have children at 105. We will see that lifetimes change significantly after the flood. It seems to me that life was much different in the ancient world. For some reason, people lived longer; a lot longer. Perhaps there was some kind of damage to the food supply caused by the flood. Perhaps, some of the good food we used to have is no longer available. It could also be that the atmosphere changed in some way because of the extreme changes brought on by such a significant event.
There is no reason to doubt the Bible record. People used to live longer and there are many possible good explanations for it.