For starters, I find the argument from complexity to have merit. A system comprising numerous dependent parts and requiring all of them for a reproductive advantage would be difficult to evolve through random mutation and natural selection.
Proponents of evolution often endeavor to hypothesize ways in which such systems could evolve through a series of intermediate steps, which brings me to my second objection: the universality of certain traits which may provide a reproductive advantage, but a very tiny one. For an example, try this experiment. Stand with your head facing straight forward, with your eyes looking ahead. Now slowly rotate your head at the neck while trying to keep your eyes pointed straight forward relative to your head. (This means that if your head is rotated 20 degrees to the left, your eyes will be pointed at 20 degrees to the left relative to your body.) As the angle of rotation increases, you'll find this becomes difficult. Your eyes "want" to rotate in their sockets the same direction as your neck, so while your head is oriented 35 degrees in one direction, your eyes will be looking at 40 degrees or so.)
This tendency is hardwired into us, and it is undeniably an advantage... it means that if you want to look at something on your periphery you'll be able to see it a fraction of a second faster than you would otherwise. But how much of a reproductive advantage does it confer? An organism with this tendency would survive an encounter with a predator that an organism without it would not if the predator approaches from a very specific angle. If the angle of approach is too shallow, an organism would see it coming even without the tendency, and if it's too deep an organism wouldn't see it coming even with the tendency. So on the average, what would the reproductive rate of the organisms with the tendency be over the organisms without it? A ratio of 1.00001 : 1? And yet the tendency is universal. How many generations would it take for a trait conferring such a minuscule advantage to become universal?
And again, this goes to all the attempts to argue against irreducible complexity by positing long strings of incremental advantage. The smaller the advantage, the longer it would take to spread. Stack a few dozen (or a few hundred) additional incremental improvements on top of that and the likelihood of the chain happening in only a few hundred million years becomes infinitesimal.
I'd also really like to know how proponents of evolution jive their theory with increasing evidence that homosexuality is a genetic trait. One would think that a trait providing such an enormous reproductive disadvantage would be wiped out in a heartbeat, on an evolutionary scale.
This is not to say that the theory that random mutation and natural selection were the sole factors shaping life is false. It may well be true. But it's certainly not proven and it certainly diserves critical scrutiny. And in a large part of the scientific mainstream, it doesn't get it. It is, as I said, treated as a religion... with heretics ostracized, ridiculed, and shunned.
ANd how have you researched their irreconcilability with evolution?
DURRRRRR I opened my Bible, of course. Haven't you heard that anybody who dares to question the orthodoxy of evolution is an imbecilic unscientific Bible-thumper?
You make several false assumptions. First, you assume that homosexuals don't have children. Second, you assume that there can be no advantage to a species in having non-reproducing individuals. Didn't you learn about the birds and the bees? Particularly the bees?
Complexity is not an arguement for design. Snowflakes are comlicated structures and no two are identical, but their formation is governed strictly by the chemical and thermodynamic characteristics of water. Therefore complexity does not prove design.
Also, specific research would need to be conducted to explore each instance of interdependence, but I'' briefly dissect the flagellum argument popularized by Behe.
THere has been research that traces the genetic history of such a biological structure. THe complexity argument that leaving out a componenet makes it non functional is a red herring. Such an argument fails to consider that an efficient structure like the flagellum evolved from a less complicated one. In reality, evidence shows that the flagellum evoultion comes from a more complicated structure where parts are removed to give the final structure. It's like building an arch. You need a support structure around it before the arch can be completed. You can't simply build it by straight addition of components. COmponents must be reomved to get the final structure.
There is a lot of research and understanding on these subfields of evolution and it would be good for your to review them. Much of this has been addressed by people more knowledgeable than I on the deep parts of evolution.
Who says all of them are required for a reproductive advantage?
Yes, it would be "difficult". And it is, which is why such systems do not evolve *frequently*. Wings, for example, have evolved only a handful of times throughout the entire history of life on Earth. However, evolution is an extremely "persistent" process, and *does* achieve many results which, at first glance, might appear hard to "believe" until you're more familiar with the actual size of the mulitipier effect inherent in the evolution of large populations. Furthermore, many system which *appear* to "require numerous dependent parts" in order to be advantageous turn out not to actually be so under examination. They can and did actually arise in a "stepwise" fashion after all.
Proponents of evolution often endeavor to hypothesize ways in which such systems could evolve through a series of intermediate steps,
...you sort of "forget" to mention the countless times when the evolutionary histories of such systems have actually been determined (not just "hypothesized") and they were found to in fact have arisen through intermediate steps, each of which would itself have been a survival advantage. Or did your creationist pamphlets just not mention that, and you *presumed* that their failulre to mention it meant that such determinations had never actually been done?
which brings me to my second objection: the universality of certain traits which may provide a reproductive advantage, but a very tiny one. For an example, try this experiment. Stand with your head facing straight forward, with your eyes looking ahead. Now slowly rotate your head at the neck while trying to keep your eyes pointed straight forward relative to your head. (This means that if your head is rotated 20 degrees to the left, your eyes will be pointed at 20 degrees to the left relative to your body.) As the angle of rotation increases, you'll find this becomes difficult. Your eyes "want" to rotate in their sockets the same direction as your neck, so while your head is oriented 35 degrees in one direction, your eyes will be looking at 40 degrees or so.) This tendency is hardwired into us, and it is undeniably an advantage... it means that if you want to look at something on your periphery you'll be able to see it a fraction of a second faster than you would otherwise. But how much of a reproductive advantage does it confer? An organism with this tendency would survive an encounter with a predator that an organism without it would not if the predator approaches from a very specific angle. If the angle of approach is too shallow, an organism would see it coming even without the tendency, and if it's too deep an organism wouldn't see it coming even with the tendency.
This is an *incredibly* cartoonish analysis. Are you under the bizarre misconception that only a life-or-death struggle with a "predator" is the only thing that can confer a selective advantage? Sheesh.
So on the average, what would the reproductive rate of the organisms with the tendency be over the organisms without it? A ratio of 1.00001 : 1?
Feel free to pull any numbers out of your ass you wish, but don't try to pretend that they have any likely match with reality.
I'm not aware of any research on your one somewhat odd example specfically (there could well be some, I just haven't seen it), but in the countless cases where the specific selective advantage of a particular trait *has* been studied in detail, it has always been found that the rate at which it became fixed in the population was well in accord with the numerical analysis thereof. The same goes for lineage-specific rates of acquisition of phenotypic mutations across time, compared to computed and directly observed rates.
So I don't know what point you're trying to make, if any, other than "wow, this boggles *my* mind, maybe that means it's impossible!"
And yet the tendency is universal.
Define "universal", please. Universal among humans? Among primates? Among vertebrates? What?
"Universality" is hardly a problem for evolution -- if a useful trait arose once, it gets passed on to all descendant groups of that lineage, and is "universal" among those groups not by any sort of magic, but by simple inheritance.
If you mean that you're baffled at how a poorly selected trait could fix (i.e., become universal) within the population, then it'll be fun to *really* boggle your mind and point out that even mutations with ZERO selective advantage actually have a decent chance to fix within a population within a relatively short timespan. See for example: Population Size and Genetic Drift
The more you actually know about biology, the less "impossible" it turns out to be. But hey, actually *learning* biology before attempting to critique it is not high up on the list of priorities of the folks whining about evolution.
How many generations would it take for a trait conferring such a minuscule advantage to become universal?
Even a trait with ZERO advantage would be expected to conditionally fix within the population in 4N generations on average, where N is the population size -- even faster if the population fragments for any reason, due to founder effects. Anything over a zero advantage would only increase the speed of fixation.
So even using a ZERO advantage for your hypothetical mutation, in a population of, say, 2,000 early primates, it would be expected to fix within the population (become universal) within 8000 generations -- using a generation time of 2 years, this means within 16,000 years. That's just a fleeting instant of time in primate evolution, which has taken place over a period of 40,000,000 years.
Any other questions?
And again, this goes to all the attempts to argue against irreducible complexity by positing long strings of incremental advantage. The smaller the advantage, the longer it would take to spread.
Again, no worse than 4N generations. it's not like it'll take a billion generations or anything.
Stack a few dozen (or a few hundred) additional incremental improvements on top of that and the likelihood of the chain happening in only a few hundred million years becomes infinitesimal.
It might if evolution proceeded in a sequential fashion as you falsely presume, but it doesn't, so...
When real-world amounts of genetic change are compared against real-world rates of acquisition of genetic changes, there's not the kind of "OH MY GOD, IT DOESN'T FIT" kind of result you seem to think must be inevitable. On the contrary, they're in very close accord. Or didn't your creationist sources cover that topic?
I'd also really like to know how proponents of evolution jive their theory with increasing evidence that homosexuality is a genetic trait. One would think that a trait providing such an enormous reproductive disadvantage would be wiped out in a heartbeat, on an evolutionary scale.
First, there's hardly "increasing evidence that homosexuality is a genetic trait". The jury is still *way* out on that question. But even if it were, your childishly simplistic "analysis" fails to take into account a number of confounding factors which torpedo your gradeschool-level consideration of the question. The most glaring omission is that you have failed to consider the possibility of heterozygous advantage -- OOPS! You have also failed to consider the possibility of the involvement of a counterbalancing associated trait, especially one that manifests more commonly than the homosexual "side effect" -- OOPS. Etc., etc., etc.
Genetics are nowhere near as simplistic as your poor understanding of them. There are many, many complicating factors and interactions which make your above "analysis" completely invalid. There are dozens of ways that a "homosexual gene" could have a *net* selective advantage in the genepool, even if homosexuality *itiself* was strictly disadvantageous. Go learn some biology and then get back to us.
This is not to say that the theory that random mutation and natural selection were the sole factors shaping life is false. It may well be true.
Gosh, I'm sure the biologists will be relieved to hear that you've extended your benefit of the doubt to their massive body of work, son.
But it's certainly not proven and it certainly diserves critical scrutiny.
...and it gets it, by people FAR more qualified than you or the Dover schoolboard.
And in a large part of the scientific mainstream, it doesn't get it.
This is, quite simply, complete bulls**t. You quite clearly have never actually had any experience with what actually takes place in "the scientific mainstream", and instead have just swallowed whole the creationist propaganda.
It is, as I said, treated as a religion...
This too, is complete bulls**t. Where do you "learn" these falsehoods, anyway?
with heretics ostracized, ridiculed, and shunned.
Please do not post your hallucinations as if they were facts.
There's no such thing as a "heretic" in science, nor is anyone "ostracized" or "shunned". Some people have richly earned ridicule, however, usually for presuming to try to teach their grandads to suck eggs without having any clue what in the hell they're actually talking about.
Case in point, this post of yours. You declare that evolutionary biology "deserves critical scrutiny", based on the fact that *you* personally aren't aware of how such points as you raise can and are and have been researched and settled in countless studies long before you ever came along, and *you* personally can't imagine how such issues can and have been reconciled to the satisfaction of working biologists who have been doing this kind of thing for over a century now.
You and the clueless schoolboards and hordes of anti-evolution creationists think that evolutionary biology needs to be "critically examined" by bewildered school students battered by waves of ignorant and usually grossly inaccurate and misleading claims by PTA moms and internet cowboys and other unqualified people who have the arrogant ignorance to barge into classrooms and say, "by gosh, if *I* don't know the answers to these things I thought up on my lunch break, these *MUST* be matters requiring 'critical examination' right away right here in the classroom by Biology101 students, because there's no way biologists might have actually already covered these topics before and found well-researched answers to them already!"
You guys crack me up.