Posted on 02/24/2006 4:12:32 AM PST by PatrickHenry
Not in a way that is more scientifically meaningful than saying one would "predict" a find of cheeseburgers at a McDonald's Restaurant.
So you think trees and cows and dinosaurs dropped out of the sky? That's your explanation of the origin of species?
"Whatever they are called, even one instance of fertile offspring proves that horses and donkeys are NOT different species."
Sure they are. The fertility rate of the offspring is almost zero (60 documented cases in 500 years of a fertile mules), and far far below replacement levels.
"natural selection" ... is merely an arbitrary way of explaining what has already taken placeand
"predict[ing]" a find of cheeseburgers at a McDonald's Restaurant?
Certainly the notion of "species" is a slippery one (and, to a large degree, arbitrary) but I think it is generally agreed that horses and donkeys are different species because they have different numbers of chromosomes, mating isn't natural and hybrid offspring are nearly always sterile.
Imagine the following situation. One billion individuals in species A. One billion individuals in species B. Both species are genetically diverse, but there is a high probability that any two individuals of A (of the opposite sex) could successfully breed; likewise B. It just happens that there is one male in species A which would produce fertile offspring with 1 female in species B if they happened to meet and "get the urge". This is an extreme example of ring speciation. In such a situation would you seriously claim that A and B are still the same species? If one of the potential co-breeders died would you still claim that they were the same species, or would you admit to a speciation event at that point? This could lead to a bizarre situation where the two groups "flickered" in and out of being the same species as the rare potential co-breeders were born and died.
The whole concept of species is a difficult one to pin down, as examples like that demonstrate.
(unless, of course, you believe in the sort of speciation that gives you nearly 7 million different species of salmon, to say nothing of tuna).
The substance of your point about salmon is unclear to me. Are you asserting that there are seven million distinct groups of salmon that have difficulty interbreeding?
Let me give you an example of what I mean (which will explain your own limitation of thought on the matter).
We both know that mammals with some history of tree`dwelling generally have full color vision. Not only do they have different sorts of photo receptors (red/green/blue, contrast), they have neural structures in their brains that are necessary to use the information stream coming from their optical receptors.
Ground dwellers, do not have this sort of color vision system.
Interestingly enough birds have full color vision. They have essentially the same brain circuitry as mammals so they can make use of the information stream.
It's almost as if birds and tree dwelling mammals had the same genes, and the Darwinians crawl through their butts to give you stories about convergent, parallel, and "new purposes for old genes" ways of accounting for this.
So, let's say there's another way genes get taken from one genome and tucked into another one. We know there's a bacteria that can do this to the sex organs of insects (creating new species because the critical parts no longer fit), but what could transport bird genes to monkeys?
What could be a simple straightforward explanation of how all the tree dwellers end up with color vision. COuld it be a bacteria? Sex crazed parakeets? Or, could both birds and mammals who live in trees be drawing from the same source of disease to obtain free floating genes that have the same effect in both forms?
And, where would those genes be found?
Since there are undoubtedly billions of different kinds of genes just floating around in the oceans in the form of viruses, maybe there's a pathway from that pool of genes to the tree dwellers so they can quickly acquire, and use, genes that give them color vision and the neural pathways to use color receptors.
Next question might be just why there might be virus genes that go into making up the genetic structure to give us color vision.
dYou do know, of course, that you have vast stretches of DNA in your genome that appear to do nothing, but they are otherwise identical to DNA elements readily found in viruses we know about, not just the billions out in the ocean.
In fact, we (meaning everybody but the bacteria) have chromosomes shaped just like those found in viruses.
Ayway, good article to read is in this month's Discover magazine. It's about the mimivirus. Provocative stuff.
I disagree with the methodology. One instance is enough.
I think that is a quite satisfactory standard to use as a test for speciation that NO INSTANCE of crossbreeding is ever seen.
"Ever" is a very long time you know!
Ok. I was viewing "successful" as resulting in offspring. But yes, the offspring are sterile.
What you do is count up the number of streams and streamlets in the PAC NW where a salmon might ever have bred. Gives you a huge count. I use 7 million since that's the biggest number I've ever seen rationally argued for.
I dispute the method. Those salmon can be physically isolated a million years and I guarantee they'll still taste like salmon!
Indeed, by that standard the number of species on earth is probably 1.
How do you know this?
It's a slipper slope for sure!
Look, if they don't taste the same a million years from now, you get back to me ya' hear!
What's your concept of Zenos Paradox, muawiyah?
As far as evolution is concerned offspring that don't produce offspring are not successful reproduction.
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