Evolution, religion, and ignorance.

[John V]

I agree with your definition, I'm just saying that part of how we determine what is and isn't a different species is genetic makeup and physiological markers. Would you not agree that if we can start with organism A and then trace its lineage down to organism B X number of generations later, and B is sufficiently genetically, physiologically and reproductively different from an example of organism A, then it would be a different species?

Possibly. The devil is in the details.

1. What do you mean by "trace its lineage"? If you're speaking of actual observation, than I'm probably on board. If you're referring to inference from differences in existing species, I disagree that that constitutes tracing a lineage.

2. How do you operationally define "sufficiently different"?

That's an offensive oversimplification; there's much more to it than that, and such support is even mentioned in the skink articles I linked. More importantly, in the case of the wall lizards, we have a record of what the initial breeding population was, and what the descendants are like, and shock horror, there are rather radical differences not only from what their ancestors were, but also when compared to another population that was placed in a different environment. Aside from their marked physiological change, an entirely new valve system had appeared in one set of the lizards owing to the new diet they had had to adapt to in this new environment, putting the lie to your claim that nothing new develops through mutations.

Do you think that all the varieties of dogs come from mutations, or selective breeding of existing variation potential from ancestral wolves? You're assuming mutation, rather than existing variation potential which expressed due to a change in environment. What should be done is to repeat it in a controlled way. Record the genome of the initial population and check subsequent generations to see exactly what happened. That would be pretty good evidence.

The short time period also works against you. Why don't we see more such change if it's so easy?

Now, these are changes to the physiology and internal structures of an organism, an introduced species for which we know exactly what the predecessor species was like, that took place over just twenty years, in a definite singular direction. Imagine what could happen over millions of years.

Scientific evidence shouldn't be based on imagination.

The evolutionary changes present in any single organism are bound to be small, which is the point; this is a gradual process that occurs in populations. I also note the clear goalpost moving: if an organism isn't different enough then you say it's the same species, and if it's notably different you just chastise us for "assuming" that it was linked to its predecessor.

It's not my fault that evolution lacks clear definitions for basic terms like species.

How the fuck does one falsify your position if you just keep oscillating between one of two claims, clearly without understanding how evolution works when it suits you?

How does one falsify a position based on imaginary extrapolation?

Speciation is change above the species level.

Seems to be change at the species level to me.

Uh, Sparky, we got that idea from your analogy: "the logical view is that small, demonstrable changes will build up, just as it's logical to consider that if I walk solidly in one direction without interruption, I will eventually have walked a mile."

Do you understand the difference between the statements "this is possible" and "this is definite in every case"?

Yes. Neither of those is present above. You say "will," which is closer to "this is definite" than "this is possible."

Do you know what the word "some" denotes in a sentence?

Yes, but that's not in the quote above.