Originally posted by Laskharis
Well... if two organisms have different numbers of chromosomes, then the process of meiosis (or is it mitosis? I can't remember) just isn't going to work. So Jimmy the Ancestral Slug, with 14 chromosomes from a chance mutation, must find another organism with 14 chromosomes with which to interbreed. Although he doesn't know this, obviously.
If his potential mate isn't of the Ancestral Slug species, then, well, there are heaps of physical factors which will prevent breeding (imagine a guinea pig trying to impregnate a falcon.)
So Jimmy's mate must also be an ancestral slug, with the chance mutation of an extra chromosome. The odds Jimmy finding Janette the Ancestral Slug are pitifully low to begin with, and even worse when you consider the extra chromothingy has probably resulted in some pretty crippling deformities. And what if they succeed in breeding? Who will their offspring breed with? The gene pool is going to get dangerously shallow. Like hillbillies...
Not a very well expressed point, but hopefully someone can help me out.
You don't know what you are talking about.
Mitosis and Meiosis is the DIVISION of cells.
Mitosis is cell division for the growth, repair and Asexual reproduction of an organism. I.e., you get a cut on your arm, your skin cells go through mitosis and repair the cut. Now, mitosis works becuase the parent cell copies itself. Let's take the human skin cell for example. The cell holds 46 chromosomes. It wants to split into 2 cells. It copies it's DNA so it has 92 chromosomes. Then the cell pulls itself apart and now there is one set of 46 chromosomes in each of the 2 resulting cells.
Meiosis is cell divison for sexual reproduction. I.e. Sperm and eggs go through meiosis. A cell starts with 46 chromosomes. then, it wants to go through meiosis, so it copies it's DNA. The cell now has 92 chromosomes. It splits and then there are 2 cells with 46 chromosomes each. Now, here's the difference between mitosis and meiosis. These two sex cells cannot combine with the sex cells of the opposite gender, because then you'd get an organism with 92 chromosomes. The female's body would recognize it as not human, and dispose of it, in a natural abortion. So, These 2 cells with 46 chromosomes each have to go through ANOTHER split, this time NOT copying their DNA. Now we have 4 cells with 23 chromosomes each. When the sperm cell with 23 chromosomes meets the egg cell with 23 chromosomes, they combine to form one cell(a zygote) with 46 chromosomes.
That poor slug with the genetic disorder is going to die alone. No babies for that one. First off, an organism with a deformity is not appealing. A female won't mate with a deformed male because the children would not survive. It's called natural selection(surprise! another aspect of evolution). Survival of the fittest.