Island said:
Uhm...
The key here is that while it's based on random mutations, the development itself is not completely random. Mutations that are a disadvantage are removed from the gene pool through the environmental conditions. Not
anything will survive (in fact, heavily mutated embryos rarely survive during the pregnancy).
However, one should always remember that mutations occur all the time and most of them are too minor to truly affect a creature's survival. It's only when minor mutations add up over the course of many, many generations that we can, retrospectively, see the species change.
We do have plenty of fossils that show various stages of human development, saying otherwise is just wrong ( http://en.wikipedia.org/wiki/Australopithecus, http://en.wikipedia.org/wiki/Homo_erectus, http://en.wikipedia.org/wiki/Homo_habilis and there are many more).
A bombardier beetle without a separation as such would not survive, true. And if it can't survive, it can't spawn children with similar genes.
As for how it could have evolved to that point: Well, I haven't read up on that specific species, but considering it'd require two different glands to produce these chemicals, it stands to reason they developed separately and any mutation that led to a loss of said separation was removed from the gene pool.
Giraffes are actually a great example for evolutionists.
In fact, Darwin based some of his theories upon them, so I'll gladly take the opportunity to recount this.
I'd have to tell a little tale about it, but I'm willing to take the time.
Imagine that, quite a long time ago, the ancestors of modern giraffes lived in the savanna. Few trees were there, but they were plentiful in leaves. Interestingly, these giraffes had rather short necks, but since there was a lot of food around, it didn't matter so much.
Now, as it is with humans, giraffes grow different in size, some are larger, some are shorter, some have longer necks, some shorter. At that time, however, all giraffes had necks significantly shorter than they are today, even the largest of the herd.
Now, a severe draught hits. We know from geological records that phases of increased temperature and phases of extreme coldness alternate naturally.
This time, however, the draught continues for several years. The savanna becomes drier and drier, the plants have difficulty to grow.
The rather short giraffes suffer as well, since their food source is dwindling. All the leaves on the lower branches in an area of many, many square miles have already been eaten and they cannot reach the higher branches because of their short necks.
However, as there are differently proportioned giraffes, some of them have an easier time reaching a few of the higher branches. While their shorter-necked cousins have a higher risk of starving, these with the slightly longer neck survive at a higher rate. And therefore they can produce more offspring which, in turn, also have slightly longer necks.
Now... imagine this happening over the course of not thousands but millions of years. Again and again. What starts off as a minor change in neck-length slowly becomes bigger and bigger as the population of short-necked animals dwindles and the longer-neck variant continues to produce offspring. And this, in a simplified and shortened way, is how giraffes developed long necks.
The argument about "great design", too, is a flawed one. We (as well as our animal cousins) aren't really that great. There are plenty of weak points in our structure as well as vestigial organs that serve no purpose any longer. However, both these things remain within us till today because they were not
enough of a hinderance to significantly reduce reproduction.
Examples include the inguinal rings, where herniae occur. The lumbosacral part of the spine, where - because of upright walking - mechanical stresses lead to an increased occurance of backpain and herniated disks (after all, we too started of as quadrupedal animals and aren't perfectly adapted to walking upright). It further includes the ligament tying truncus coeliacus and intestine together, where the latter may strangle itself. The list goes on. Much of it can be seen when looking at the anatomy of the human body or typical diseases that haunt us as a species. All of these things, however, were not harmful enough to be removed from the gene pool.
Vestigial organs, there's a list of them on wiki if you're interested.
If we truly were designed, it'd have been a pretty lazy and careless designer.
The fact of the matter is that we were created through eons of mutation and natural selection. It's an amazing process, no doubt about that, but there's also no doubt about it in the scientific community that both the astounding things as well as the weaknesses within us are the result of natural selection.
As for your last sentiment, this is definitely a good way to go about it. After all, science is all about doubting everything you see before you and replacing current theories with new ones when new and better evidence comes along. However, intelligent design has
no support whatsoever beyond being
simpler. But let me ask you this: What's the simpler solution? Zeus throwing bolts of lightning or a build-up of electrical potential between cloud and ground, resulting in an electrical discharge with all its implications about ions and electrons and electric fields? Is the simplified Occam's Razor (simplest answer = best answer) really true? Doesn't it just lead us to accepting things we believe we know about the world instead of doubting them and researching them in earnest? Wouldn't this kind of acceptance result in total stagnation?
Anyway, until something better than the current theory of evolution comes along, I'll stick with it.
