Why is evolution so controversial?

What 50,000 year period was that? Or don't you realize that the two sets of data you give ...

• 50,000 to 100,000 years ago the population was 3,000 to 10,000 people and
• circa 70,000 years ago the population was 1,000 to 10,000 people

... are different estimates talking about the same bottleneck event? Don't you realize that they are actually in agreement within their ranges of error?Or don't you realize that the statement "between 50,000 and 100,000 years ago, human populations sharply decreased to 3,000—10,000 surviving individuals" means that at some time between 50,000 and 100,000 years ago the population hit that level, not that it held at that level for the whole 50,000 year period?Really? Except that it isn't purely exponential. It doesn't matter to me what foil you use on your head, your argument is wrong, demonstrably wrong ... Glad you liked it (was it a good feast?): it shows graphically that the human race has not grown along a purely exponential curve, but has plateaued several times as the resources have run down for supporting further growth.What your simplistic approach fails to account for are the effects of the death rate and how that varies with food supply and climate and plague etc. Curiously ANY species that remains at effective zero growth rate for ANY extend period of time is actually doing a lot better than the majority of species that have gone extinct.EnjoyEdited by RAZD, : clrty

And yet it is trivial to prove that this cannot always have been the case. Unless you have proof otherwise. Show us a 50,000 year old lightbulb and we'll rethink that. Otherwise, we evolutionists will just go on believing what all the evidence shows.

Your point was nonsense to begin with and it is still nonsense. As we have repeatedly pointed out and explained to you over and over and over again. That's odd, because when I wrote back in 1991 it was precisely for the purpose of addressing your point. Are you naturally an idiot or do you just work extra hard at being one?And if you have not bothered to read it, then how could you claim to know everything about it? Do you also have delusions of godhood and believe yourself to be omniscient? No, that is a lie. We know that it is a lie because we have answered your "point" more than a dozen times and have explained it to you just as many times.You have already received your answer, but you just wish to ignore it. Since you have ignored your answer for more than a dozen times, we see no reason to believe that you will not continue to ignore it the next six dozen times.You're just being an idiot, which appears to be your MO here and, I would guess, in the rest of your life. How's that working for you?Also, you have never answered my question!. Where did you learn your distorted form of math in which constants are variable? Which I now follow with the question: Is it too late for you to get a refund from that school for having mis-educated you?Now, since you keep displaying an ignorance of mathematics, let me point out something to you about your own equation that I'm sure you've never heard before:P = P₀e^rtFor r > 0, the curve is an exponential increase.
For r < 0, the curve is an exponential decay (ie, values get progressively lower)
For r = 0, the curve is a straight horizontal line.Furthermore, the value of r is defined as the difference between the birth rate, b, and the death rate, d, such that r = (b - d) (we already saw this in Olnick's books and in that Wikipedia article). Therefore:
If there are more births than deaths, then b > d and r > 0 and the population increases.
If there are more deaths than births, then b < d and r < 0 and the population decreases.
If there are the same number of births as there are of deaths, then b = d and r = 0 and the population remains constant with effective zero population growth.Simple mathematics. Do the math. The recorded reports of human population is part of history, which only came into existence with the invention of writing, which did not happen until shortly after 3000 BCE. That means that our records of human population levels are less than 5000 years old. That only covers one tenth of the time span that your "point" is talking about.The invention of writing -- and hence of population level records -- came after the formation of cities, which itself came after the development of agriculture and of the domestication of livestock. All of those inventions had dramatic effects on a group of people's ability to become larger, for a population to grow beyond its earlier limits. Certainly far beyond the ability of a hunter-gatherer society to grow a larger population.We have historical records and direct observations of all kinds of subsistence methods, so we both know that they exist and we also know their economics. We know that in every society they need to obtain their means of subsistence from the land and that different types of societies with different levels of technology will be able to support different population sizes from a given area of land.In gaming, there is a discipline called "world building", in which they take the rules of reality to come up with an artificial world in which to set their game. They take this discipline very seriously and have studied the factors extensively, drawing from scholarly works and historical records. This is from a classic essay, "From Land to Subsistence" (http://tinybatman.com/add/library/land_to_subsistence.htm):

quote:

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DENSITY = reference population density per squaremile or squarekm in reference situation: no wasteland, no uninhabited land, yield=1. Density depends on the subsistance type of the culture. You can also figure the effect of technology and crop cycles in here.

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Subsistence density	sqmil density	sqkm
Nomad                       5            2
Seminomad                  10            4
Semisedentary              50           20
Sedentary                 100           40
Industrial                more         more

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Here are some population densities (actual average densities, _not_reference densities):
Arctic: 0.3 / sqmil
Kalahari desert: 1 / sqmil
Canadian praries: 2 / sqmil
Medieval England: 30 / sqmil
Modern Estonia: 88 / sqmil
Modern Hungary: 280 / sqmil
Modern Bangladesh: 2400 / sqmil

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I've seen suggestions that hunter-collectors must keep their population below about 2/sqmil or run into environmental degradation problems.

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Hunter-gatherers cannot have more than 2 to 5 people living in one square mile, meaning that with their subsistence technology they can only feed 2 to 5 people for every square mile of land. What would their daily range be? 5 to 10 miles? So a group that occupies 100 square miles can number no more than 200 to 500.How is that group supposed to experience the phenomenal exponential growth that your model demands? Oh, sure, you think, they could just split into two groups and one group can just move over to the next 100 square-mile plot, but they can't, because there's already another group occupying that land. We're right back on that island again. The land that they occupy can only support a small number of people and no more. As they grow to the maximum population size that their land can support (ie, its carrying capacity -- does that term sound at all familiar?), then their numbers will cease to increase and they will enter into a state of effective zero population growth.There is your answer yet again! Human population levels in prehistory were kept low and fairly constant by the low carrying capacities of their habitats. Population levels could only begin to increase when changes in our subsistence technology allowed the carrying capacities of our habitats to increase. But until those changes in subsistence technology happened, the ability of our populations to grow rapidly could not happen.But of course, you are yet again going to be an idiot and ignore the answer.

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Even if humans have always grown exponentially - would you agree that this will not always be so?

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Well I have never backed off the fact that human population follows an exponential curve. The continuous-growth formula is accepted in all kinds of scientific fields. It is a good statistical tool to determine future population levels. I generalized a (r) to cover the entire human growth history from 1300 bc (I admit this is not very accurate).Here are contemporary growth rates: That is between .013 to .02 for the value of (r). As I have maintained all along growth rates vary (adjust the r).Now a growth rate for 400 bc when Israel entered Egypt. That would be about (.018) for 700 entering Egypt and 1 million exiting. Does this seem so fantastic?

Now you can answer the question How could a breeding population of humans remain at effective zero growth for 50,000 years?

If you are prepared to do some math, I can give you an example of how this might happen. Also let's define effective growth to mean the average size of the population over a long period divided by the length of the period.Model a simple situation in which humans are primarily hunters and have some situation say a predator, disease etc which acts successfully on the population with some probability. If you are pretty good at math, you can also add some ability to use secondary food stuffs. Once you've constructed the equations, evaluate what happens as you very the effectiveness of hunters and their opposition and of the prey.This is an exercise that is easily done using a system of ordinary, first order differential equations. You'll note that some of the scenarios result in the population of humans oscillating between upper and lower values. The scenarios of course are not totally realistic, but they should give you enough reason to never have to ask this kind of silly question ever again.

The model is used in those situations where it fits.Mathematically, the exponential curve results from a fairly simple model in which birth and death rates are proportional to the population and no other variables are needed. It fits things like radioactive decay very well. But outside of problems in elementary school math books, it is not seriously used to determine population levels when we know that other factors are involved.

Your posts are too wordy, just condense the thoughtYou have never answered my question. How can human population growth hover around zero for 50,000 years with an initial population of 10,000. This is ridiculous and in need of explanation.

And yet the graph that you supped on shows this to be a false statement. What reality shows is population growth that takes off when a new adaptation reduced constraints on growth, and then constrained growth as those adaptations reached their maturity. Curiously, the oldest anatomically modern humans date to 160,000 years ago, not "50,000 or 70,000" years ago. Why is that? Or are you under the common creationist misunderstanding that evolution must cause continual change? The natural history of life on earth is littered with species in virtual stasis for much longer periods; this is something that usually occurs when (a) the species is well adapted to their habitat and (b) there are no changes to that habitat. You will note that humans have taken the need to adapt to changing or different habitats out of the equation by adapting technology to provide the necessary fitness adaptations, thus there is not much need for any visible physical adaptations.You might want to read Sexual Selection, Stasis, Runaway Selection, Dimorphism, & Human Evolution ...... and I think you will find that the human population does continue to evolve: certainly it evolves immunities to fight diseases (do I need to discuss the effect of immunity to disease on the invasion of the Americas by Europeans?).If you think that humans need to adapt and change physically, then what pressure would be behind that need and what would you expect to see.For myself I see further development of the brain, something that can change a lot without showing much difference in fossils because the change is in the soft tissues. I also note that certain athletic records are consistently broken by newer generations. Evolution does not have to be dramatic to occur: it just needs opportunity (mutations) and fitness (selection).Humans have been selecting for larger heads to the point where further head enlargement often results in death to mother and\or child (see section on runaway sexual evolution in thread above), a problem not seen in other species, certainly not in other apes.Humans have also been selecting for barer and younger appearing people, especially women, to the point where there are now whole industries built around providing artificial adaptations and exploiting sexual selection via "photo-shopping" of models until they no longer look the way real people look -- that runaway sexual selection is still operating. You seem to be under a mistaken impression that human selection is for intellectual improvement: that Nobel Prize winners are major sex symbols rather than the pop music rock stars ... or have you just not thought about it ... ?What is much more likely (and more in alignment with the evidence) is that sexual selection is for young creative people -- the singers and the dancers, the artists and the musicians -- and that brain size and attendant intellectual growth came along for the ride. Technology reared it's head when the first tool was used. Or the last 200 years when we learned to apply the scientific method to understanding the world around us instead of myth and magic thinking. What we have learned is built on the foundations of what was known before, whittling away the concepts that don't pan out to leave us with a better and better approximation of the nature of reality.Or the last 50 years when we learned to make machines to think and solve problems?Enjoy.Edited by RAZD, : clrty

Liar!I have answered your fucking question! Repeatedly! You're just being idiot! And you have not yet answered MY question!ANSWER MY QUESTION, HYPOCRITE!

As has been explained to you. This would be possible if b ≈ d, that is if r ≈ 0. You haven't explained why such a state of affairs is not possible, despite it being a fundamental part of the population growth curve. Here is a high school standard explanation of this. Would you like to start with any follow up questions or are you happy repeating the same one?Edited by Modulous, : No reason given.

It is used in population gains for bacteria samples, wild fish populations etc. all the time I believe it is a good local approximation You really need to address the zero population growth over 50,000 years. I still say that a local calculated (r) can estimate population gains for humans.

Not that the stuff you say is reliable, but did you not make the claim below: What should we make of your new values for r? That you're in a corner and will say anything?Once characteristic of an exponential growth curve is that they are always concave upward (form a bowl holding water rather than dumping water). Why don't the curves for known population points, such as the ones RAZD provided, show such behavior?

Here is a short post, hopefully short enough for you.Modern humans are far older than 6,000 years.I'll be glad to provide evidence if you want.

I provided the limitations on using exponential growth and you did not respond to them. The curves cannot be used on wild fish populations other than for brief periods. What do your curves say about the fishing in Cape Cod, for example. I have done so in another post. But so have others. Again, if you are willing to chose short enough periods for each constant r, including allowing r to be 0 or negative at times, you can model any curve. Which means your observation is meaningless. Edited by NoNukes, : No reason given.