In the first sentence of your post, you say that two organisms with different numbers of chromosomes "cannot" procreate. Then, in the end of your post, you say that they
can procreate but that a viable offspring is unlikely. Which is it?
I'll save you the effort: It's the second one. You were quite wrong when you said, early in your post, that different numbers of chromosomes prevent organisms from procreating. Organisms with different numbers of chromosomes can and do reproduce sexually and yield viable offspring. You are correct, however, insofar as viable offspring are often less likely when the parents have a mismatched number of chromosomes. That can indeed cause a problem. But of course, as any intelligent person should realize, "unlikely" isn't the same as "impossible". Bear in mind that we're talking about huge numbers of organisms mating over huge expanses of time. Even something that's "highly unlikely" to occur in any given single case becomes somewhat more likely when you give it a hundred billion chances. And in fact in many cases it's not that unlikely; it can be quite easy for organisms with different numbers of chromosomes to produce offspring that are not infertile.
As for how and when the chromosome count changes during speciation, that's no mystery either. The process of chromosomes breaking (or fusing, for that matter) is fairly well understood. In the case of breaking apart, it happens during mitosis when chromosomes with duplicated centromeres are pulled in opposite directions by the spindle fibers.
http://scienceblogs.com/pharyngula/2...osome_numb.php
Here's a site with a pretty easy-to-follow explanation, if you can stomach taking a science lesson from a gol'durned liberal atheist. I can't help noticing that you mocked gwahir for allegedly having a shallow grasp of the topic... but then when asked to elaborate on your objections to evolutionary theory, you chose such an elementary and easily-answered question as "where do the new chromosomes come from, huh?!"
Where did you think they come from... the invisible Hand of the Designer reaches into cell nuclei when it's time for speciation to occur and magically inserts the right number of new chromosomes?
Bookmarks