Sunday, December 23, 2018

Evolution Rates: Stark Contrast Between Observed and Postulated


I have on more than one occasion had a dialogue with my friends who accept evolution which goes something like this: They point to a small difference which doubtless could occur by known processes and postulate that all change we see occurred via similar mechanisms. I counter that it is unsound to extrapolate that data so far as to be an explanation for great differences. I then try to show that evolution has a rate problem. That is, even if given enough time unguided nature could do everything they say it did, the question is really whether or not it is plausibly for it to be done in the time available. I point to evidence that known natural mechanisms don't operate at the rate required to explain the changes observed, even if you grant an old earth.

A perfect example showed up in the news this week. Scientists have been able to get what they think are more accurate dates on the period of vast change sometimes called the "Cambrian Explosion". They think the transition from Ecidarian to Cambrian occurred over less than 410,000 years, a much narrower window than the 5-10 million they were previously able to narrow it down to. That is just outrageously fast considering that life on earth went from animals with the complexity of sponges to pretty much every phyla of life on earth showing up right then- including some no longer with us. How did all that diversity occur so fast? By known evolutionary processes? That's absurd. 

If you want to see how fast known evolutionary processes work, see this article about speciation released the same week. The bottom line is that over the course of three million years a population of howler monkeys seems to have split into two "species".  The "split" is far from complete as they are still so close that hybridization occurs where the two populations mix. After three million years one population of Howler Monkeys has had an incomplete split into two populations. That's an example of how fast natural selection works in the real world. And while there are faster examples available they are always or almost always the result of a shuffling of existing genes, not the accumulation of new ones as would be necessary for the sort of macro-evolution my naturalist friends think happened. 

So there you have it. They can document an incomplete split of populations of Howler Monkeys over three million years and they think the same processes are responsible for what we see in the Cambrian- where dozens of new phyla appear in a mere fraction of the time. My protests that there must have been something else going on there- an unseen hand operating in the past which is no longer doing that now, are met with irritation and indignation. Which I guess would be OK, if it were paired with real answers. It's not.

Macro-evolution has a rate problem. Taken across the broad expanse of time (538 million years since the Cambrian began) it is noticeable. When you zoom in on the periods of greatest change it is glaring. The most often-used tactic of my more naturalist-leaning friends to my protests is to focus on the human-chimp differences and stress how that genetic gap is not so large given the supposed time between purported ancestors. Then they assume that if the observed naturalistic rate of change is within parameters for that particular example then they can minimize or ignore the large picture I am pointing to.

I find this baffling. If I might give an analogy, it would be like my claiming that a certain species of worms had help travelling based on my observing repeated instances of them showing up thousands of miles away in a short period of time. Maybe humans took them there, maybe a migrating bird stored them in their gullets. I don't know, I just know the idea that they crawled to their new locations on their own is negated by the rate problem. They simply don't move fast enough to have made that trip on their own. My evolutionist friend replies by giving an instance where the worm populations are spotted only half a mile away a year later. In that instance it is quite possible they did make the trip under their own power. Not proven mind you, but possible given the short distance between the two points and the speed of the worms. My evolutionary friend then considers his case to be won.

Of course it isn't won. He or she is simply pointing to an instance where the "naturalistic" explanation is possible and then assuming that this establishes it as true. This is done whist ignoring all the instances where the rate problem suggests that their hypothesis is implausible. This is terrible reasoning but I have seen it done by brilliant people. In actuality the instances where the "naturalistic" explanation is plausible don't at all change the facts that there are instances where it does not. Even if we have more precise measurements available on the case where the worms stay close it doesn't change the fact that the other measurements still present a problem for their case which should be addressed rather than waived off. In particular since just showing that it is possible that the worms got from "A" to "B" on their own power in some instances does not at all prove that is how they got their in all such instances. 


Please "like" and "share".This is a conversation that the church needs to have!


2 comments:

  1. It's like you don't understand how the environmental factors that drive evolution might change with time and geography or that rates of reproduction and number of offspring vary between species.

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  2. Nice of you to come out of those deep Oregon woods to post here. I understand how rates can change, within a range. Just like I understand the speed of a car can change depending on the time and the model- like a Model T at 20mph vs. a modern Porsche at 220mph. If if you are clocking something at 2,200mph, its not a car. And when you see change at the rate it was in the Cambrian Explosion, its not the same evolutionary mechanisms we see now. Those don't operate anywhere near that fast no matter what animal you are looking at.

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