Why is evolution so controversial?

Would you be surprised if there is no answer for a zero growth rate in human population. I have been needling you for a answer that does not exist. You seem like a good sport I would like to talk to you again Thanks for the exchange.

EnjoyEdited by RAZD, : typical creationist attempt to will away the evidence

There are several answers to his question in this thread. Zaius did not acknowledge, let alone address a single one of them. He simply declared himself the winner.He is not an idiot. He's a fraud. I'm pretty sure that matches the opinion I formed of him the last time he was here.

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There are several answers to his question in this thread.

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I am not joking about this, there is no answer. You see one near extinction event after another does not do the job of keeping down the diversity of the population. As soon as the population grows past 10,000 individuals, pocket isolation drives up the diversity. The population must be keep homogenous. The compared genomes of all humans today is observed to be homogenous in this manner. If you allow a bumpy multitude of near extinction events a homogenous population is not sustained . The growth percentage must remain literally zero over 50,000 years.That is like balancing a bowling ball on the head of a pencil. It has never been seen in any wild population ever. You balance your bowling ball on the pencil, I will accept a recent origin of our species.

Naturally, given that I just gave you the answer. Nice concession speech: but given your attitude I am struggling to think what would motivate me to engage in a discussion with you in the future.

A statement which makes absolutely no sense at all. Horse caca. You don't even try to make any defense for any of this nonsense.As far as diversity goes, what matters is who survives and how high the mutation rate is. You have to take into account the selection pressure on the population, which is not something I see in your proposition. At a high enough selection pressure, more variation is screened out as unfit for survival.The other problem is that 10,000 people only supports a limited amount of diversity, particularly given a set of relatively recent common ancestors which would be the case in a cycling population size. Any new diversity would have to come from mutations if there is no introduction of diversity from outside the group. Over time, the population may be distinct from their ancestors, but possibly not from their siblings and immediate predecessors.Nobody thinks you are joking. But there is no reason to take you seriously either Mr. Point still stands after being refuted.Edited by NoNukes, : No reason given.

No, your position is a joke, whether you realize it or not -- because it has been invalidated by objective empirical evidence that contradicts what you claim. Your position is a joke because you fail to understand the evidence for a population bottleneck from two different sources are talking about the same singular event. Your position is a joke because you think "between 50,000 and 100,000 years ago" is a 50,000 year long period rather than the approximate range within which a bottleneck event occurred. Another way to say it is that 75,000 +/- 25,000 years ago a population bottleneck event occurred. Curiously this compares quite well with the data from newer more accurate source that says the same singular population bottleneck event occurred ~70,000 years ago. One event, two different sets of data that are conscilient, reinforcing each other and giving us greater confidence in the results. There was only one bottleneck period in Homo sapiens history. Because mutations continue to occur and selection continues to occur. After a stochastic bottleneck event the selection pressure on the remaining population for stable phenotype is removed and so diversity will increase after that event at a higher rate than in a mature population in stasis with their ecology. Curious as to how you arrived at the "10,000 individuals" number -- without documentation and evidence it is just another claim you have pulled out of your posterior region. Not necessarily. Populations in genetic isolation have different selection pressures and will adapt via fitness selection in different ways. If the habitats are very similar then the selection process will be similar. If there is occasional gene flow then mixing with the main population will still occur. Moving into pocket habitats does not mean genetic isolation occurs. Why? If subpopulations remain genetically isolated then speciation can occur, just as has happened in the past (there are several sister Homo species in the past, one of them is Homo neanderthalensis).It is obvious from the world around you that the human population is NOT homogeneous, but has many varieties (races) that are observably distinct even though inter-breeding can and does occur. This is no different that different varieties in other species showing some distinctive geographical variations while maintaining inter-breeding capability.But there is no requirement for all Homo sapiens descendants to stay in the Homo sapiens species. Divergence can occur as it has in the past.And distinct varieties can develop while remaining in the Homo sapiens species and not staying homogeneous in non-breeding areas of the genome. Not true. Genetic mapping of genetic variations shows distinct geographical branching of several genotype variations within the species as a whole.People are all classed within the Homo sapiens species because they can (and do) inter-breed, not because their whole genomes are similar. Again, there was only one (1) bottleneck event. Nor does it have to be homogeneous, it just requires sexual compatibility for reproduction to remain in the same species. That is a small subset of the genome. And again you fail to understand that the period of the extinction event was not 50,000 years but a brief period within an approximate 50,000 year accuracy range -- at some point between 50,000 years ago and 100,000 years ago a brief bottleneck event occurred ... at some point around 75,000 years ago (+/- 25,000 years) a brief bottleneck event occurred -- an estimate that is now confirmed by new data showing that approximately 70,000 years ago a brief bottleneck event occurred -- ONE event, One brief bottleneck event. False (1) -- Do some research on punctuated equilibrium and the evidence for much longer periods of stasis in some species.False (2) -- our species origin occurred circa 160,000 years ago.Repeating false claims and opinions does not make them any more valid than when they were first refuted, it just shows a stubborn inability to accept your errors. Cognitive dissonance in full display.Enjoy.Edited by RAZD, :

Your argument consists of vague disjointed rambling without any actual math. To the extent to which it is meaningful, it is obviously false: "near extinction events" would, obviously, not make the population more heterogeneous.

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Why? If subpopulations remain genetically isolated then speciation can occur, just as has happened in the past (there are several sister Homo species in the past, one of them is Homo neanderthalensis).

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Neanderthals are clearly not a different species than man If they could interbreed frequently Your definition is not my definition of a species.

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It is obvious from the world around you that the human population is NOT homogeneous, but has many varieties (races) that are observably distinct even though inter-breeding can and does occur. This is no different that different varieties in other species showing some distinctive geographical variations while maintaining inter-breeding capability.

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My definition of homogeneous here refers particularly to the genome. In the sense that humanity shows considerable linkage disequilibrium in the population genome. in fact the claim has been that this linkage disequilibrium has been stable in the human genome for about 5 million years and cross over has just manifested itself in the last 5000 years. (research by John Hawks Ph.D., University of Michigan, 1999
Associate Professor of Anthropology At UW-Madison since 2002)

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But there is no requirement for all Homo sapiens descendants to stay in the Homo sapiens species. Divergence can occur as it has in the past.
And distinct varieties can develop while remaining in the Homo sapiens species and not staying homogeneous in non-breeding areas of the genome.

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Your perspective is purely from common descent. Which I have effectively argued against in this thread. No common descent from a HCLCA dictates Homo sapiens are in stasis.Edited by zaius137, : Pasting error....

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No, your position is a joke, whether you realize it or not -- because it has been invalidated by objective empirical evidence that contradicts what you claim.

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Please present the empirical evidence, I have only run across contradictory speculation in the papers I have seen.

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Your position is a joke because you fail to understand the evidence for a population bottleneck from two different sources are talking about the same singular event.

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Please be specific. Without writing a novel.

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Your position is a joke because you think "between 50,000 and 100,000 years ago" is a 50,000 year long period rather than the approximate range within which a bottleneck event occurred.

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My friend to explain linkage disequilibrium in the human genome, there is no recovery except for extended time frames, some as long as 100,000 years.

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Another way to say it is that 75,000 +/- 25,000 years ago a population bottleneck event occurred. Curiously this compares quite well with the data from newer more accurate source that says the same singular population bottleneck event occurred ~70,000 years ago. One event, two different sets of data that are conscilient, reinforcing each other and giving us greater confidence in the results.

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Authorities have issued conflicting theories in that area. As far as I know the recovery time is still tens of thousands of years. I am particularly interested in you showing me a proposed recovery time.

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And again you fail to understand that the period of the extinction event was not 50,000 years but a brief period within an approximate 50,000 year accuracy range -- at some point between 50,000 years ago and 100,000 years ago a brief bottleneck event occurred ... at some point around 75,000 years ago (+/- 25,000 years) a brief bottleneck event occurred -- an estimate that is now confirmed by new data showing that approximately 70,000 years ago a brief bottleneck event occurred -- ONE event, One brief bottleneck event.

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Again no citation I can look atPlease less Razmataz and more citation... thanksEdited by zaius137, : No reason given.

Let's do some real math, if only to demonstrate what it looks like.So, let T = [T₁,T₂], and define a set F of functions T → R⁺, where each function in F represents one possible function of population with respect to time over the time interval [T₁,T₂].Note that for any n in the natural numbers, there is a function k_n in F given by k_n(t) = n for all t in T.We may define a function H : F → [0,1] given by saying that H(f) is the (average, statistically expected) heterozygosity of the population at time T₂ if the population over the time interval was given by f(t).For convenience, let us write that for any f, g in F we have f < g if and only if f(t) < g(t) for all t in T. It is evident that if f < g then H(f) < H(g), and in particular if f(t) < n for all t, i.e. f < k_n, then H(f) < H(k_n); similarly if k_n < g(t) then H(k_n) < H(g).Choosing any such f, g in F, we can of course construct a function j_λ in F given by j_λ(t) = ( 1-λ )f(t) + λg(t), which is well-defined, indeed sensibly defined, for λ in [0,1].Now it is evident that H(j_λ) is a function of λ and that this function is well-defined, continuous, and in fact monotonic over the domain [0,1]. By the intermediate value theorem, there is a value of λ such that H(j_λ) = H(k_n).Now it is trivially the case that we can choose an infinite number of pairs of functions fitting the bill for f and g as given above, such that the two functions are themselves linearly independent, and such that they do not form a basis for any member of any other pair on the list. And for any two such functions, as we have seen, there will be a linear combination such that H of that combination is equal to H of kn.

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It follows that: for any constant population size n, there exists an infinitely large number of distinct functions of population size with respect to time which will produce the same heterozygosity as though the population had been at that constant size over the same interval.

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So instead of saying "That is like balancing a bowling ball on the head of a pencil", zaius should have written: "This is like 'balancing' a bowling ball anywhere on an infinitely large and completely flat plain."

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(A pedant might object that the codomain of the functions in F should have been N, and that our conclusion should have read "very very large". On the other hand, T is not discrete, since time is not neatly broken up into generations for our convenience, and this would justify "infinitely large" after all. But all this is splitting hairs: zaius is completely wrong, and that's what matters.)

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Edited by Dr Adequate, : No reason given.

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Edited by Dr Adequate, : No reason given.

Indeed.And when the only constraint on the equations is having the same beginning and end points, while ignoring the intermediate points, it becomes mundanely obvious that the number of possible equations is infinite.It also becomes mundanely obvious that virtually all such equations will fail to model the intermediate points. Some will, of course, model occasional intermediate points, in the way a straight line and a sinusoidal curve will model intermediate points, while diverging significantly in other places.This demonstrates that math can model reality, but cannot constrain it or control it or force reality to match the model.Enjoy

OK DocI honestly could not follow your reasoning.I think stability in this case can best be represented by a phase-plot using population dynamics. The logistic model is:

Setting the differential to zero, two zero growth crossings are found, one stable the other unstable. The upper population (N (k)) is dictated by the carrying capacity of the environment and growth is exponential to that point. The lower population(N(0)) is the population dictated by the statistical model needed to fulfill the requirement of the bottleneck and is determined by statistics (some low population over long time spans). I want to make it clear that carrying capacity is variable per the environment. Any "assigned population" on the populaten axis will exhibit the same instability as the first crossing point.It is a bowling ball resting on the head of a pencil.All the details found here:NO REDIRECTEdited by zaius137, : No reason given.Edited by zaius137, : No reason given.Edited by Admin, : Make equations more easily visible.

Curiously I have already presented it -- that you failed to understand it is not my fault. (Search thread for your post with "supper" in it). Which I have been. You confuse two different avenues of data as being about two different events, instead of one confirming the other, and you confuse uncertainty with exactly when within a 50,000 year window that event occurred with it lasting 50,000 years. These are comprehension problems on your end.You continue to make these mistakes. If you don't want a novel in response then reduce the errors in your posts to one at a time. Curiously this is in response to posts you have made with these numbers, so you are accusing me of failing to provide citations for material you used? Really?Perhaps you need to look back at where you got those numbers. So you take a speculative extreme view as fact because it suits your beliefs ...Another approach would be to start with understanding how bottleneck\founder events affect a species in general, and then seeing if that applies or not to the human situation.Population bottleneck - Wikipedia

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A population bottleneck is a sharp reduction in the size of a population due to environmental events (such as earthquakes, floods, fires, or droughts) or human activities (such as genocide). Such events can reduce the variation in the gene pool of a population. After an event, a smaller population (of animals/people), with a correspondingly smaller genetic diversity, remains to pass on genes to future generations of offspring. ...

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Population bottleneck followed by recovery or extinction

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... The population of American bison (Bison bison) fell due to overhunting, nearly leading to extinction around the year 1890, though it has since begun to recover (see table).

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Year	American bison (est)
Before 1492	60,000,000
1890	750
2000	360,000

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A classic example of a population bottleneck is that of the northern elephant seal, whose population fell to about 30 in the 1890s. Although it now numbers in the hundreds of thousands, ...

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From this simple sampling of actual data and information, three things should be mundanely obvious to the casual observer:

1. that the recovery from a bottleneck\founding event is highly variable between one extreme leading to extinction and another limited by the malthusian pure growth model (that in fact there are an infinite number of possible recovery rates), and
2. that thousands of years of recovery did not occur for bison or elephant seals^(*),
3. that recovery depends on a number of factors involving the fitness of the population to survive and reproduce in their current habitats, not on some pre-determined mathematical model of growth.

^(*) which depends on your definition of "recovery" -- you could argue that the (full) recovery has not occurred yet because those animal populations have not yet reached their previous size and genetic diversity. This of course contradicts your claim that the recovery period is characterized by a constant population with zero net growth.Or you could argue that recovery depends on when the species reaches a level of population and genetic diversity that they are no longer considered "endangered" ... another subjective categorization.Or you could argue that once the population starts to grow that it has recovered.Either way we do not see a necessary flat-lined recovery for "tens of thousands of years" ... which is your (indefensible\ill-defined) argument.If the bottleneck\founder event is stochastic (chance unrelated to fitness) and does not cause an extreme change to the habitat, then there is every reason to believe that the survivors are a random sample of the previous population that was adapted to the ecological habitat that exists following the event and should be well positioned to grow and evolve to fill the available resources and carrying capacity of that habitat.Thus an event that lasted one generation in affecting the habitat would be followed by near malthusian pure growth recovery until it started reaching the carrying capacity of the habitat, presumable the level of population before the event. Perhaps you should stop denigrating information and pay attention to the facts and empirical evidence rather than letting pet beliefs lead you off into untenable positions.Enjoy

Summary: you're completely wrong. The one that shows that the logistic equation has a stable equilibrium? Er ... what we're looking at here is something saying that a population of zero is unstable, but that logistic growth necessary is stable around the population K --- i.e. it's not like a pencil balanced on its end, but like a marble at the bottom of a hemispherical pit.When you yourself cite things that show that you're completely wrong, this is maybe a sign that you don't understand them.Edited by Dr Adequate, : No reason given.Edited by Dr Adequate, : No reason given.