Thanks for posting this. Great info!

...you just conceded that no adaptive pressure we know of would compel homologous resemblance, and adaptive pressures drive evolution, so it seems to me you need to refine the argument.

If adaptive pressures were the only constraints on evolution, then you would be correct. However, natural selection also has the important constraint that it has to work with the lineage that it's given; it can't double back or redesign parts from scratch. The fact that dolphins have five metacarpals rather than two or eleven is not the result of selection amongst competing early dolphin forms with different numbers of fingers, but the fact that dolphins are descended from pentadactyl ancestors. This is what's meant by 'there's no adaptive reason for dolphins to have five fingers'.

Why must homologous resemblance be evidence of limitation or constraint? [Makes an analogy computer programming]

The difference is that computer programmers don't call up functions that they don't need, and they can call up any function that they like. If somebody were programming a dolphin, they wouldn't say "I need a fin, so I'm going to call up the pentadactyl limb function and force it to be fin-like with an awkward kluge", they would just call up any of the perfectly good fin functions that they already coded when they were working on Fish 1.0. An even better example of this is ostrich wings. Ostrich wings are really well-adapted to flight, which they can't do because they're stuck to ostriches. Ostriches use them to balance when running and in courtship displays. To switch metaphors for a bit: giving ostriches beautiful bird wings to use for balance and rudimentary communication is like buying a new MacBook Pro and using it to drive nails. However, I'm probably just tiring out my fingers because:

Nothing in the concept of LUCA conflicts with the idea that an intelligent being created the current panoply of life.

As has been pointed out before: no possible observation conflicts with the idea that an intelligent being created the current panoply of life, provided that we make him* capricious enough. The idea is entirely immune to falsification.

*And yes, in this context, it is nearly always a 'him'.

Why conflate dissent with dishonesty? I see religious people make this mistake all the time when they assume atheists simply don't believe because they are moral scoundrels or something similar. Are you seriously beyond even entertaining the possibility that you might be wrong, or that you might be the one misunderstanding Wells? I'd be more impressed if you invited Wells to respond, because I bet he'd explain his arguments quite differently than you have.

..the fact that both humans and dolphins have five finger bones (in dolphins, buried in their fins) is an example of homology, because no adaptive necessity that we know of would compel such a similarity of structure.

Well, I agree that the pentadactyl limb design dolphins and humans share is an example of homology. I disagree that such is an example of homology "because no adaptive necessity that we know of would compel such a similarity of structure," but hold that thought for a second.

As with the similarities in vertebrate embryos, the homology among living creatures is an observation.

Correct...

Evolution is an explanation for that observation,

Yet, you just conceded that no adaptive pressure we know of would compel homologous resemblance, and adaptive pressures drive evolution, so it seems to me you need to refine the argument.

Designers, particularly omnipotent ones, are not constrained by past history in their work. They are not limited to variations or elaborations on designs they've already produced.

Why must homologous resemblance be evidence of limitation or constraint? Your rebuttal to the "common-design" argument misses the mark because its conclusion does not flow from its premise. The phenomenon of homologous resemblance accompanied by differentiation in function supports the argument from special creation, with nothing more than an analogy from computer science and a quick reference to scripture. Any programmer worth their money knows to write a function for chunks of code that demand iteration. In doing so, the programmer enjoys the resourcefulness of simply calling the function rather than retyping the entire sequence of code, which is an enormous waste of time and also invites a large margin of error. This might be trivial if we're writing a simple script that spits an image to a browser upon refresh, but the amount of code needed to create even a simple living cell is immensely more complicated (I am not saying 'irreducibly complex'). If you as an all-powerful, creative being decided to create a different type or kind, would you want to rewrite the necessary genetic codes from scratch? Or would you create an autonomous function that simply copies and tweaks existing code?

Even though the bodies of living creatures have changed dramatically to adapt to different environments, they still retain the deep similarities that point to their common descent from ancient ancestors.

Correct, yet moot. Nothing in the concept of LUCA conflicts with the idea that an intelligent being created the current panoply of life.

Neoteny is real, but this example isn't.

Neoteny is obviously not the only process involved in turning chimps into humans, but I stand by my argument. See:

Penin X, Berge C, Baylac M. "Ontogenetic study of the skull in modern humans and the common chimpanzees: neotenic hypothesis reconsidered with a tridimensional Procrustes analysis." Am J Phys Anthropol. 2002 May;118(1):50-62. (Abstract)

We used the skulls of 41 Homo sapiens and 50 Pan troglodytes at various stages of growth. The Procrustes superimposition of all specimens was completed by statistical procedures (principal component analysis, multivariate regression, and discriminant function) to calculate separately size-related shape changes (allometry common to chimpanzees and humans), and interspecific shape differences (discriminant function). The results confirm the neotenic theory of the human skull...

At the end of growth, the adult skull in humans reaches an allometric shape (size-related shape) which is equivalent to that of juvenile chimpanzees with no permanent teeth, and a size which is equivalent to that of adult chimpanzees.

Aside from the classic mammal limbs illustration, what are other good examples of homology, ebon?

Another good example is the human appendix, which is homologous to the cecum, a digestive organ used by herbivores to store symbiotic bacteria that help them digest cellulose.

Aside from the classic mammal limbs illustration, what are other good examples of homology, ebon?

Comment #8 by: Juan Felipe

Gill-bones and mandibles. Brain architecture.

I never heard about that one. It's so hard to keep up with the goings on in these cults!

There was a scriptural dispute. The deuterostomes believe that one should develop ass-first, where the proterostomes feel that this ontogeny is ass-backwards.

the deuterostome-protostome split.

I never heard about that one. It's so hard to keep up with the goings on in these cults!