drfeelgood said:
Actually, the idea is there, and the logic is there. Remove the six digits if you want. It does not invalidate the argument that there is a mechanism in place to limit speciation, although malfunctions do occur. Please note that the 6th digit, or a tail in another example, is an example of a malfunction of the system, not born from necessity to survive. It never represents an advantage to the species, it does not create a new species, nor is it exactly common. Also, provide evidence that a parent with 6 digits gives birth to offspring with 6 digits. Or a someone born with a "tail" giving birth to someone with a "tail".
Remember, I'm not as smart as some of the others around here, but I'll attempt to reply as best I can...
You're assuming that mutations are there for the sole purpose of being advantageous to the species. That is not true. A mutation is a mutation, just that. However, there are some mutations which are more advantageous than others, and
those ensure the bearer of such a mutation to a better chance of
spreading that mutation. Therefore, the mutation spreads throughout the
entire population. Remember, an advantageous mutation is a mutation that allows the bearer to beat the pressures put on him by his environment. For instance, prey animals have eyes on the sides of their head, so that they can see farther around, while hunting animals have both their eyes in the front of their head, allowing them depth perception (unless you have Double Vision, like me, my right eye points in a touch). Why do we not see the bad mutations repeating? Because those who are unfortunate enough to bear those bad mutations are much more easily killed off, not allowing them to spread that mutation.
As well, the mutated gene may or may not be a
dominant one. In the case of the unfortunate boy with a tail, if he were to reproduce, it may or may not show up in his children. Infact, it probably won't.
Also, a point on speciation. You're assuming that speciation occurs within a single population group. That's incorrect. There are kinda two kinds. For instance, a population in the
same area might experience a mutation being spread through the population. Because they all share the same pressures, the same mutations are good and bad. So they
will speciate, but since there is no pre-species in which to compare, we cannot test the fact that they are reproductively isolated.
As with the chimps and the humans, a group of chimps
moved away from the main body, so they were under
different pressures than the main-body chimpanzees. So, they, as a collective, underwent a series of Micro-Evolutions, that
culminated in them being reproductively isolated. You're failing to grasp that a
long chain of Micro-Evolutions will lead to speciation, or Macro-Evolution, and that Macro-Evolution is simply a nice way of bundling up a series of
observed Micro-Evolutions in a definable chain. A simple way of classifying a series of Micro-Evolutions.
I hope I was clear.
The following is part of my edit:
I figured that you might go slack-jawed at the likelihood of a series of random mutations not only being beneficial, but dominant. However, think of it like the system that drives enzyme reactions, kinetic energy. Now, I'm assuming that you accept the theory that the more energy you put into a enzyme / substrate system, the more they'll do, since the more energy the two have, the more likely that the proper enzyme will hit the proper substrate. It's completely random, and yet it works.
It's the same thing with populations. The chances are, indeed, slim, but given large populations and millions of years, wonderful things can happen.