Summations Only

If a population of a few dozen people are capable of supporting themselves, their population with persist. And you're right - they don't need the capability to support anyone else - just their own group.If, however, they're incapable of supporting anyone else, their population cannot grow. There's a limit to how many people an environment will support, until you develop technologies that can increase the food supply.

This few dozen people wouldn't exist in isolation. There would be gene flow between them and adjacent populations. The point being made is simply that population size doesn't increase if the enviornment lacks the capacity to support a larger population.

There have always been limits to how many people an area will support. It is only in the modern age that we have overcome many of them, to allow our population to rise to such a large level.If you're living in a hunter-gatherer society, the amount of food available to support your population depends on how much food there is around. This is a simple and undeniable fact. If the amount of food in a given area which people are able to obtain is only enough to feed 200 people a year, then only 200 people can live in that area. If there are more, some will starve, or kill each other fighting over the scarce resources.The carrying capacity of each area varies a lot, of course. Hunter-gatherers in the Pacific Northwest could live at much higher densities than those in the Kalahari, because there's a lot more food lying around for the pickings. But once you're eating everything available then there's nothing more to eat!The only way you can increase the population beyond an environment's carrying capacity is to increase the carrying capacity, usually by some technological innovation. Better hunting techniques that allow you to catch more animals to eat. Or, the one you mention - the domestication of animals and crops. Before there was farming in Europe, all Europe's fertile land was already occupied; by hunter-gatherers. But there were less peopl then, than there were after farmers made this fertile land produce more available food.

Let's try a thought experiment. Imagine we have a volcanic island, out in the ocean miles away from anywhere. The island is approximately two acres square. The land is quite fertile, thanks to the volcanic dust, so a lot of the land can be farmed. The inhabitants have basic farming technology. Let's put 200 people on that island, and then gradually keep adding more.As more people are added, there are more hands to work the farmland. Do you believe, then, that we could keep adding people indefinitely and that the food supply would indefinitely increase, or not?

I was using a simplified hypothetical example to make plain the fact that there are constraints on population - it doesn't simply grow magically and consistently.But if, instead, you just want to look at an actual historical example of population, fine. These figures are for the population of Great Britain. Up till 1801, they're based on a consensus figure from the Insitute of Historical Research, of the University of London.43: 1,000,000
410: 1,500,000
865: 1,500,000
1000: 1,500,000
1348: 3,500,000
1350: 2,250,000
1642: 6,000,000
1649: 5,700,000
1801: 10,942,646
1851: 27,368,736
1911: 45,221,615Notice that the population did not grow at any steady or consistent rate. It was reduced by plagues (1350) and war (1649) and, for long periods, remained basically stable. The population at the time of the Norman Conquest, as estimated from archaeological remains, historical records and what we know of agricultural technology at the time, was about the same as it had been 700 years earlier at the time of the Romans.

First things first. The 'natural selection theory' says nothing about the population of Europe 70 thousand years ago. This is the province of historical demography.And from where did you pull these random figures? The people who try and figure out pre-historical populations do so by considering how many people a land can support, based on the technology they used at the time and the climate at the time.Here's the abstract of a study from the Journal of Archaeological Science which tries and estimate the population of Europe in prehistoric times. It deals not with the time period you mentioned, but the one immediately following it. They looked at the distribution of archaelogical sites in this period, and at the climate records, and obtained a figure of around about 5,000 people between the time from 50,000 to 25,000 years ago. There's a wide margin of error included in their calculations, since this is obviously difficult to be precise about, so their 95% confidence interval puts the population between 1,700 and 37,700 people.After this, the population would have decreased, because we know that the climate got colder and made much of the continent uninhabitable - they retreated into refuges. Once things started to warm up, the population would have increased again as people recolonised the more hospitable continent. They estimate it grew to between 11,300 and 72,600 people.To carry on further, the basis of calculations need to change, because agriculture was introduced to Europe, allowing much greater food production and greater population growth.That's how historical demography is done, by looking at the evidence of the real world. We don't need your back of an envelope calcuations based around numbers you pulled out of the air and which ignore the realities of technological and climatic limitations to growth.

The figures from the Institute for Historical Research were the ones I quoted before. I believe I found them in a BBC feature on population change in Britain, but now I can't find the same page again. The figures for 1801 onwards are from the census.I'm unclear from CrazyDiamond7's latest response if this means he's accepting these estimates, since the purpose of presenting them was to demonstrate that population growth doesn't proceed in any definite fashion, being limited by resources and affected by contingent events. One of the key points was supposed to be that the population didn't change a great deal for about 1,000 years, then increased about 40-fold over the next thousand years.ABE: Some of the figures based on the "Evolution theory for the origin of the Human body" also appear to be from one of my posts, which were taking from this article abstract on an anthropology blog. It's an attempt to estimate the pre-agricultural population of Europe.The figures have been misinterpreted though.1,700 - 37,700 people is the error margin for the population over the whole period from 50,000 years ago to the Last Glacial Maximum. It is not supposed to represent a beginning and end point.I've no idea where the pre-50,000 BC figures are supposed to come from.Edited by caffeine, : No reason given.

I'm not sure how many more ways to try and explain this.You say that, taking two points in history and looking at the population, there is always a 'multiplication rate' between the two.If, by this, you mean that population has always increased between two points, this is clearly not true.Sometimes, the population has decreased between two points.Sometimes, it has remained static.You keep demanding us to invent models of population growth. Here's an invented model which could explain the fact that the population of Britain didn't change significantly during the medieval period:Each pair of breeding adults has, on average, six offspring.On average, three of these die as children. Of those who survive, again on average, one doesn't have any children due to dying, or being sterlie, or horrendously unnatractive, or joining a nunnery, or whatever other reason you'd like.This produces a population growth rate of 0. Problem solved.