“It would seem that lions and tigers are the same species.”

Lions and tigers are definitely not the same species. Neither male nor female ligers are reproductively fertile.

How many ligers have been raised to maturity and tested for sterility that you feel so confident they are sterile instead of just having arbitrarily less chance of successful conception than their parents? I sincerly doubt enough individual ligers have been tested to reach any reasonably certain conclusions aside from saying none so far have demonstrated the ability to conceive. But feel free to provide data that proves me wrong. -ds

Check out the following links:
http://www.greenapple.com/~jor.....ossesa.htm

It would seem that wolves, coyotes and jackels are all one species. It would seem that bison and cattle are the same species. It would seem that lions and tigers are the same species. It would seem that african and indian elephants are the same species.

However, let me suggest that biology has effectively abandoned that classic definition of a species — defined by it’s ability to produce fertile offspring. A new definition, describes as groups which remain genetically isolated, has taken its place. Because of the new definition, polar and grizzly bears get their own species designation. So do wolves and coyotes. The advantage of this approach is that a whole lot more biologists get the privelage of naming a species. Ain’t that exciting? BTW, by the classic definition the glapagos finches are not a separate species. They are quite capable of mating with mainland finches.

We know that all dog VARIETIES breed with one another. They are very diverse–chihuahuas versus Great Danes; they are the product of artificial selection; and they all represent the same species. Africans are homo sapiens. Germans are homo sapiens. Germans are well suited to cold climates. Africans are suited to hot climates. But they are the SAME SPECIES. My argument–and it still stands–is the neo-Darwinists glibly say, “Oh, this is a separate species from that one over there. And (much like you’ve argued) they’re adapted to their environments JUST LIKE DARWIN “predicted”.” Yet the reality is, that most of the time they really don’t know what they’re talking about.

Added to this point is that the ‘lumping’ together of grizzlies and polar bears narrows the apparent ‘plasticity’ that Darwinism assumes exists in animals. If Darwinists are mistaken with other putative designations of species, then Darwinism becomes even more suspect.

Neo-Darwinism and Last Common Ancestor. I wonder if its misleading to think of LCAs? If we think in a neo-Darwinian mode for a while, where all biological novelty arises from Randon Mutations RMs (generating events) and Naturan Selection NS (filtering events). From some ancestor of the Grizzly which was not a Grizzly, there was a sequence of RMs and some NS over time leading to the Grizzly’s in the Rockies. The RMs acted on the germ line genomes in the sequence. Between any two animals in this breeding sequence there could be 0,1,2 or more differences in their genomes caused by mutations. All passed for a while at least their fitness test. They survived long enough to breed. Now think about the sequence of animals involved. I would guess the mutations from breeding pair to offspring were few, meaning there would have been a more or less closely related chain of animals from the ancestor of the Grizzly we started with to the modern Grizzly.

If the neo-Darwinian paradigm is vaguely correct we should see chains of relatedness between all life. Currently we see great gaps everywhere.

So I’d suggest, when you are working in a neo-Darwinian mode you think of chains of closely related life forms separated by at least one mutation rather than LCAs. The notion of a LCA seems to me to obscure what neo-Darwinism predicts: closely related chains of life forms separated by mutation in germ line genomes. In neo-Darwinian space your LCA would likely be the animal next to you sharing the same environment as you and just as fit as you.

The same can be said for the various “species” of Darwin’s finches in the Galapagos. They are all the same species in that they have compatible genomes. Selection has led to different gene frequencies that create different behaviors and physical characteristics in these birds, but their genome is the same, and actually under certain conditions they all will interbreed and produce fertile offspring.

Darwin’s finches, which by legend is what led Darwin to his theory, do not exhibit evolution at all. What we see is selection acting to promote or suppress the frequency of pre-existing genes within a the gene pool of a single species.

Stu Harris
http://www.theidbookstore.com

It is hard to grasp the time scales involved. To get a gut feeling for it, it helps to translate it into something more familiar. Here’s an analogy that I find helpful. First, turn the years into distance so that 1 mm represents 1 year. (If you think easier in English units than metric, 1 mm is about 1/25 inches.) Then 65 million years translates to 65 kilometers (about 40 miles). 250,000 years, by contrast, translates to just 250 meters (about 820 feet).

When really large distances are involved, I like to take it a step further and figure how long it would take to drive that distance at 65 miles / hour. 65 million years, at 1 mm per year, would take about 37 minutes to drive. 250,000 years would take just 8.6 seconds.