Rate of genetic Mutation - debating a christian - help if you can

Hello,

 

I'm debating with a christian friend on Facebook, and she threw something out that I have never seen:

 

" I understand that it [evolution] is a very gradual process, which is why it is mathematically impossible. I will have to look up the exact rate of mutation in DNA, but it is something like 1/1*10^33 replication. If you multiply that out based on that rate, rate of replication, rate of fission, then mitosis, and eventually mitosis, then it doesn't matter how gradual the process is, there hasn't been enough time in the last 300 billion years."

 

 

I have no idea what this is, and for once google isn't very helpful. Anyone know what this is/where it comes from?

 

Thanks!

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If we look at sexual reproduction, (as opposed to asexual), then it is only mutations in sex cells, (ova and sperm), which count. But the human male ejaculate holds about 300,000,000 sperms, so that's a lot of replications in each ejaculate, and how many times does a male animal ejaculate in its life? Lots anyway. Have you ever seen a video, (or the real thing), of coral releasing sperms and ova? There are billions of them (I'd guess). Similarly for fish when they release sperm.

Also see:-
Dr. Lindemann's Sperm Facts
http://www2.oakland.edu/biology/lindemann/spermfacts.htm

Now of course each sperm only fertilises one egg, but that's a lot of replicating on the male side, for mutations to occur. I can't offer much on the real mathematics involved in all this, but even if the figure given of 1/1*10^33 mutations per replication is correct, there is this other side to the story, ie. the huge number of replications going on in sperm production.

That figure of 1/1*10^33 replication may be a bit suspect, ie. low. Cancer seems to be quite prevalent in humans and other species, and cancer is a mutational effect, although it does not have much bearing on evolutionary change, because these mutations aren't passed down the hereditary line, (although a genetic effect to make a family more prone to getting cancer may be). However, the prevalence of cancer suggests that mutations may be higher than the figure cited.

I am sure that the actual calculations are very involved, and the 1/1*10^33 is almost certainly a 'red herring' value.

Just to add to this rate of replication idea. It occurred to me that in sexual reproduction as I discussed above, one might say that the species in question are all of a higher order, (more complex / multi-cellular). To go to the other end of the scale take bacteria.

Bacteria divide by binary fission, and: {Providing no mutational event occurs the resulting daughter cells are genetically identical to the original cell. Hence, "local doubling" of the bacterial population occurs. Both daughter cells from the division do not necessarily survive. However, if the number surviving exceeds unity on average, the bacterial population undergoes exponential growth}; (http://en.wikipedia.org/wiki/Bacterial_growth).

{Generation times for bacterial species growing in nature may be as short as 15 minutes or as long as several days}; (http://www.textbookofbacteriology.net/growth.html)

 

At high school, I learned that under ideal conditions and as a rule of thumb, bacteria divide every 20 minutes or so. This means that starting from a single bacterium, and under ideal conditions, the mass of bacteria produced in 24 hours would be more than the mass of the entire earth. Every 20 minutes, the population would go 1 . . . 2, 4, 8, 16, 32  . . . etc. After each time block, the population becomes 2^n, (ie. 2 to the power n). After 20 minutes the population would be 2 ^ 1 = 2 etc. In a day there are 24 x 3 = 72 time blocks of 20 minutes, so by then the population would be 2 ^ 72 = 4722366482869645213696 and that's one heck of a lot of bacteria.

 

This itself is a red herring value, because the population of bacteria would run out of space and food, long before the 24 hours were up, and as mentioned above, not every daughter cell survives. Nonetheless, taking all of this subjectively, it is still a heck of a lot of replication.

 

So the objection in the OP about there not having been enough replication to lead to evolution, looks very shaky indeed.


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