show_no_mercy

I don't have the in-depth knowledge of evolution to correct this reply:

Mageth

Others, I'm sure, will contribute more substantial criticisms. I'll just note that that analysis seems to assume one "change" at a time, occurring linearly. Almost like it's only one creature that's evolving, and only one change can occur at a time. The truth is that it's a population that evolves, and there can of course be more than one, or even many, beneficial "genetic changes" that occur in a population in each generation, or even in an individual, that then get selected for. Massive parallel processing, in other words.

I also question the speculation on how many genetic changes are necessary to get from the "first mammal" to the modern human. Maybe someone has an actual scientific estimate for that, rather than just a speculation.

Oh, and the implication that "humans haven't changed (haven't had any genetic changes) in the last 4000 years" is suspect to say the least (it's true that, morphologically, we're quite similar to humans 4000 years ago, but that doesn't mean we haven't experienced genetic changes as a species in the last 4000 years), and even if that was the case, that would not imply that "genetic changes" only happen every 4000 years, and then only one at a time.

show_no_mercy

That's something that initially struck me, but I wanted a more informed reply than what I could currently write. There's only a 2% difference in DNA between a chimp (a mammal that's hunched with hair) and a human. This is just a speculation on my part, though.

Plognark

Well shit, i'd imagine billions (if not trillions) simultaneously existing rodents and proto-mammals, even with mutation rates that low, would be able to come up with the 200,000 mutations cited in one measley little reproducitve cycle.

Looks like another classic example of an arrogant dimwit who think he knows a hell of a lot more than he actually does.

theyeti

This is your first and biggest problem. Where does your friend get this number from? How does he justify it? There are fewer than 50,000 genes in the human genome, and most of them are phenotypically indistinguishable from those in other mammals. You can make very slight modifications to some genes, particularly those involved in development, and get highly significant changes in phenotype. So where on Earth does the 1 million "changes" come from? (And note that "changes" is not a unit of measurement.)

The argument is entirely meaningless unless there is a quantifiable unit of change, a known rate of change, and some idea as to what the number of required changes happens to be. Actually, it's not that hard to do, and if you do it, you see that the numbers don't support creationism at all.

Let's take a simplistic example in which we want to know how long it took the human and chimp genomes to diverge as much as they have (about 1.5%). With a genome of about 3.2 E9, and with each lineage accounting for 0.75% each, there needed to be about 2.4 E7 mutations in the human lineage to account for the divergence. The mutation rate is between 1E-8 and 1E-9 per nucelotide per generation. If we use a number in the middle, then it takes 1.5 E6 generations to produce 2.4 E7 mutations. If we assume 5 years per generation (which would have been typical for most of our evolution, and is close to the chimp generation time), then it would take 7.5 million years for humans and chimps to diverge, which is right in line with the fossil record.

Of course, this is a simplistic example that ignores selection, recombination, in/dels, and a host of other factors. But the bottom line is, there is no evidence that there were too many "changes" required to account for human evolution.

theyeti

travc

The main fallacy is indeed the "linearity" assumpton. Evolution operates on populations, and in this example, entire classes of organisms. A single species can go along for several million years (or even much longer) without demonstrating any significant morphological changes, but there are lots and lots of species that are changing at the same time.

Then of course there are changes induced or exposed by changes in the evironment (changing selective pressures) and co-evolutonary interations. Puctuated equilibirium fits in there.

Sensei Meela

Ask your friend to 'google' the term "pleiotropy."

Kingreaper

and lets use every 4 thousand years now, we know for a fact humans haven't changed in that amount of time (lets even say we are about to change sometime soon)



Have they missed all the freaky mutant tall people (ya know, the NBA)?

What about those freaky mutant people wioth two toes?

What about htose freaky mutant people with lower cholesterol?

Those freaky mutant people with all that extra muscle mass?

All those freaky mutant people with no pigmentation?

Those freaky mutant people with tails?

etc. etc.

anthrosciguy

As soon as you hear them start with "let's assume" you really have to wonder why you're supposed to assume what they want to assume. Tell them "let's assume your assumptions are completely wrong".

KeithHarwood

What about all the freaky mutants with blonde hair?

Or the even freakier ones with red hair?

Or the downright weird ones who can taste cabbage?