“Low population growth, virtually no population growth, and negative population growth for tens of thousands of years results in a poplulation of less than 1 million people aft some 250,000 years. So, the admonition that you are using false assumptions about the population growth rates and the significance of populaton declines is directly relvant to waht you posted above.”
The poster I was responding to was not talking about tens of thousands of year periods, but periods of centuries, which is what the topic of my reply was. You want to move the goalposts and talk about thousands of year contractions, which basically proves my point. A few centuries IS insignificant, if you posit a 100,000 year plus time scale, unless those contractions were extraordinarily severe.
Actually a couple of centuries of population decline still matter even if the overall timeline is 100,000 or more years. If you’re positing at 1% annual growth then 1 year of -1% growth (decline) is taking 2 years out of your graph, the year of decline and the year to make it back. If your decline gets larger the effect on your graph gets worse. 1 century of 2% decline just cost your graph 300 years. That doesn’t even get into things like known sharp contractions like the Black Death, that chopped off 1/4 of the world’s population in 2 years. One or two of those will tear your graph to pieces, and there have been dozens.
“A few centuries IS insignificant, if you posit a 100,000 year plus time scale, unless those contractions were extraordinarily severe.”
Again, you are making a raft load of totally wrong assumptions. You assume the birth and survival rate from the average was applicable to the early periods, when they certainly were not. You wrongly assume the pandemics did not affect enough people in the short term of a few centuries or less to have a significant enough effect to preclude a millenia eqrlier exponential population explosion like the one that occurred in the last two or three centuries.
You ignore how reducing a population to zero in the space of only one year has the effect of extinction despite the average population growth which erroneously assumes a continued population growth into the future years of a populaton that no longer exists at all. Likewise, a population that has been severely pruned to 70 perent or 10 percent of its former numbers is going to take considerably longer to return to its former numbers, especially if and when conditions do not permit an annual increase in numbers for most of the following centuries or a number of millenia.
This is especially true in the prehistorical period when natural catastrophes cause all but one of the hominids to become extinct, and the surviving hominid, Homo sapien sapiens was nearly made extinct as well. It doesn’t do much good to have 120,000 years of bare existence and miniscule increases in population when something like an asteroid impact comes along and reduces your population to barely more than a thousand individuals who must eke out a barely sustainable existence for survival for millenia to come as the environmental conditions recover.