Posted: Aug 28, 2010 2:28 pm
The whole point, though, Wuffy, is that evidence in quantity has been provided demonstrating that real human population numbers do not conform to Stevebee's naive constant doubling assertion. The REAL path of human population numbers has been a long, complex one, with ups and downs throughout the 200,000 year existence of our species in its approximately present form. Initially, the population was restrained by carrying capacity - at its simplest, how much food was available to them, though carrying capacity considered rigorously includes other factors - however, even considering the simplified case still drives a tank battalion through Stevebee's assertion. However, human population grew as humans started slowly moving out of Africa into other parts of the world, but in those parts of the world. carrying capacity still acted as a brake upon exponential growth, and kept numbers restrained because there's a limit to how many hunter gatherer humans a given tract of land can support. During this long period of expansion, which was spread over several millennia because humans were limited to walking as their means of moving into new locations, population was subject to various local rises and falls, subject to such variables as weather (and how that impacted upon food availability), the appearance of virulent strains of pathogenic micro-organisms that resulted in severe depopulation or even extinction of local tribal groups in some places, predation, and assorted natural disasters.
In fact, it probably wouldn't take long to write a computer program to simulate this slow migration process, and determine courtesy of this, that this process alone makes a mockery of Steve's assertion that population doubling held uniformly throughout the entire history of the human species, because population growth by expansion into new territory is restricted by the fact that such growth can only take place at the edge of the population - carrying capacity stops population growth away from the edge of expansion, and population expansion by migration can only increase proportional to the area of territory migrated into, which means that expansion during this period was closer to a t2 type function than an at type function. If you write such a simulation, and store the population numbers in an array year on year, you can determine if this is the case, quite simply, by performing a log-log transform plot of the data over time. If you perform a log-log transform plot, and end up with a straight line whose slope is equal to 2 (within the limits of experimental error of course), then your population growth function is of the form at2, where a is an appropriate constant of proportionality. In fact, I might have fun doing this myself with a quick bit of Visual Basic code to see what happens.
Then, of course, we hit the next brake, which is the point where humans have colonised all possible available land areas. At this point, carrying capacity brings expansion to a halt once more, and again, human population number manifestly do not conform to Steve's naive assertion.
At this point, however, something interesting happens. Humans alight upon the idea of growing food. Humans discover farming. Which means that now, the carrying capacity of those environments where farming is possible has increased, and population can begin expanding again. Welcome to the dawn of civilisation.
However, human population numbers are still limited by the new carrying capacity, and when human numbers start to approach that, the brakes are applied to population increase once more. Don't forget, also, that humans are still, during this period, subject to the vagaries of weather, disease, predation (though to a more limited extent than before once urbanisation starts to grow apace), and consequently, population variation is again marked by local rises and falls due to these factors. Plus, we now have to factor in a new variable - the propensity of humans to engage in internecine warfare. During the hunter-gatherer stage, when groups were small, and encounters relatively infrequent, internecine warfare was a minor contributor to population dynamics, but with the advent of civilisation, and the advent of organised warfare, this becomes a larger contributor to population dynamics, as humans are now able to engage in killing each other on a scale not previously possible. During the hunter gatherer stage, tribal conflict would probably result in fatalities of the order of between 10 and 100, but once humans organised into societies, and these started to develop armies, a single encounter could result in 10,000 or more dead. This, of course, would be limited by technology, but would still involve two to three orders of magnitude of increased capability in this area.
This situation persists for another few millennia, until we reach the stage where Europeans start developing science, and start applying the knowledge obtained thereby to a whole host of relevant areas - farming, transport, and of course, the technology of war - and then start engaging in the process of imperial conquest. There's another rise in numbers, as Europeans equipped with ever more sophisticated science-based farming, transport and military technology start a new wave of colonisation, frequently displacing or exterminating outright indigenous humans not possessing those tools, and start moving from being a primarily agricultural species to a species increasingly possessing an industrial capability. Only once a science-based industrial capability is widely available, which has only been a recent development, do we see human numbers undergo an exponential rise of the sort Steve wishes to postulate took place throughout the entire history of our species, and despite being repeatedly told that applying recent data to a past in which entirely different conditions applied is plain, flat, wrong, he refuses to accept this basic fact, and pretends that his naive assertion dictates how real human population dynamics has behaved throughout human history.
But then, is anyone surprised at this? Creationists operate on the basis of believing that their pet wishful thinking dictates to reality, and that reality is obliged to conform to whatever wacky ideas they dream up. The idea of shaping one's ideas to fit reality is wholly alien to them, and Steve has demonstrated this on an epic scale in this thread, by continually refusing to accept the basic idea that when your assertions and reality disagree, it's your assertions that are wrong, not reality.
In fact, it probably wouldn't take long to write a computer program to simulate this slow migration process, and determine courtesy of this, that this process alone makes a mockery of Steve's assertion that population doubling held uniformly throughout the entire history of the human species, because population growth by expansion into new territory is restricted by the fact that such growth can only take place at the edge of the population - carrying capacity stops population growth away from the edge of expansion, and population expansion by migration can only increase proportional to the area of territory migrated into, which means that expansion during this period was closer to a t2 type function than an at type function. If you write such a simulation, and store the population numbers in an array year on year, you can determine if this is the case, quite simply, by performing a log-log transform plot of the data over time. If you perform a log-log transform plot, and end up with a straight line whose slope is equal to 2 (within the limits of experimental error of course), then your population growth function is of the form at2, where a is an appropriate constant of proportionality. In fact, I might have fun doing this myself with a quick bit of Visual Basic code to see what happens.
Then, of course, we hit the next brake, which is the point where humans have colonised all possible available land areas. At this point, carrying capacity brings expansion to a halt once more, and again, human population number manifestly do not conform to Steve's naive assertion.
At this point, however, something interesting happens. Humans alight upon the idea of growing food. Humans discover farming. Which means that now, the carrying capacity of those environments where farming is possible has increased, and population can begin expanding again. Welcome to the dawn of civilisation.
However, human population numbers are still limited by the new carrying capacity, and when human numbers start to approach that, the brakes are applied to population increase once more. Don't forget, also, that humans are still, during this period, subject to the vagaries of weather, disease, predation (though to a more limited extent than before once urbanisation starts to grow apace), and consequently, population variation is again marked by local rises and falls due to these factors. Plus, we now have to factor in a new variable - the propensity of humans to engage in internecine warfare. During the hunter-gatherer stage, when groups were small, and encounters relatively infrequent, internecine warfare was a minor contributor to population dynamics, but with the advent of civilisation, and the advent of organised warfare, this becomes a larger contributor to population dynamics, as humans are now able to engage in killing each other on a scale not previously possible. During the hunter gatherer stage, tribal conflict would probably result in fatalities of the order of between 10 and 100, but once humans organised into societies, and these started to develop armies, a single encounter could result in 10,000 or more dead. This, of course, would be limited by technology, but would still involve two to three orders of magnitude of increased capability in this area.
This situation persists for another few millennia, until we reach the stage where Europeans start developing science, and start applying the knowledge obtained thereby to a whole host of relevant areas - farming, transport, and of course, the technology of war - and then start engaging in the process of imperial conquest. There's another rise in numbers, as Europeans equipped with ever more sophisticated science-based farming, transport and military technology start a new wave of colonisation, frequently displacing or exterminating outright indigenous humans not possessing those tools, and start moving from being a primarily agricultural species to a species increasingly possessing an industrial capability. Only once a science-based industrial capability is widely available, which has only been a recent development, do we see human numbers undergo an exponential rise of the sort Steve wishes to postulate took place throughout the entire history of our species, and despite being repeatedly told that applying recent data to a past in which entirely different conditions applied is plain, flat, wrong, he refuses to accept this basic fact, and pretends that his naive assertion dictates how real human population dynamics has behaved throughout human history.
But then, is anyone surprised at this? Creationists operate on the basis of believing that their pet wishful thinking dictates to reality, and that reality is obliged to conform to whatever wacky ideas they dream up. The idea of shaping one's ideas to fit reality is wholly alien to them, and Steve has demonstrated this on an epic scale in this thread, by continually refusing to accept the basic idea that when your assertions and reality disagree, it's your assertions that are wrong, not reality.