Evolution’s Speed – My Assumptions and First Guesses

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This is part of a series: How Fast is Evolution?
Previous: How to Find Evolution’s Limit
Next: Evolution’s Speed – What Kinds of Mutations Are There?

In my previous post, I laid out my idea of how to test for evolution’s limit (irreducible complexity) in a lab.  Basically I’d try so many mutations on so many creatures that I’d be almost guaranteed to get a good one – assuming, of course, that life really appeared by evolution.

I have a big problem, though: I need a really big population to make this work.  Based on what I currently know of genetics, I might need such a big population that even a lake full of bacteria wouldn’t be big enough.

As I do the math to find out if my idea is practical, here are some assumptions I’m making.  I’ll also make some educated guesses about what would really happen.

Assumptions I’m making:

  1. All mutations are copying errors
    This is the conventional wisdom, but I’m not so sure.  For the purpose of this series, I’ll assume that they are, and I’ll use the best stats I can find on mutation rates.
    Depending on which study you read, the human mutation rate is anywhere between 56 and 103 base pairs per generation.  To me, this just seems too high.  New genetic diseases strike perhaps 2.5% of people.  Not all mutations cause genetic diseases, but if the vast majority of the human genome does something, surely a big chunk of all mutations would cause noticeable genetic diseases.  I strongly suspect that many of these “mutations” are actually intentional.  Perhaps they’re genetic switches or self-optimizing genetic code.
  2. Experiments are more reliable than fossils
    I’m going to focus mainly on experimental evidence – stuff that’s measured in a lab today.  I simply don’t trust evolutionist fossilologists to correctly interpret fossils and other stuff buried a long time ago.  As an example of how bad their judgement can get, it took most of them 45 years to realize that Piltdown Man was a fraud.
  3. All creatures have the same mutation rates
    I make this one out of necessity.  It looks like genome sequencing technology hasn’t advanced enough to make it easy to measure mutation rates accurately.
  4. The best available data is accurate
    Again, I make this one out of necessity.

Here are a couple of predictions I’m making:

  1. If this experiment turns out to be practical, it’ll show one of these:
    1. Evolution tends to slow down even if the environment changes once in a while
      This would be inconsistent with punctuated equilibrium, which says that evolution happens in relatively short spurts as a creature adapts to its environment.  Once it’s adapted fairly well, it’s supposed to pretty much stop until the environment changes again.
    2. Evolution happens so slow that even 4 billion years isn’t nearly enough
      This should already be obvious, but here’s some of the math.  Compare this to the overall mutation rate of 56-103 base pairs per generation.  If:

      1. The human genome has 3.2 billion base pairs
      2. The human genome is 99% the same as chimpanzees (1% of 3.2 billion = 32 million), and
      3. Humans took 5 to 8 million years to split from chimps, then
      4. Assuming that each species changed just as much (350 million / 2 = 16 million mutations to go from chimp ancestor to modern human), approximately 2-3 good mutations have to take over each year on average, and
      5. Assuming a generation time of 10-20 years over that entire time, we should see 20-60 good mutations take over per generation (2 * 10 = 20, 3 * 20 = 60).  If they’re taking over, they should be very obvious.  So where are they?
  2. Even if it’s impractical to mutate as big of a population as I would need to test for irreducible complexity, I still expect that this experiment would show that devolution happens faster than evolution.

EDIT: I’ll have to look into whether the above quoted mutation rates include all types of mutations, or just point mutations.

This is part of a series: How Fast is Evolution?
Previous: How to Find Evolution’s Limit
Next: Evolution’s Speed – What Kinds of Mutations Are There?

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