It would if Dollo’s Law actually worked the way Feduccia thinks. But of course it doesn’t. The “law” (the term overstates its force) refers to complex adaptations, not simple events like limbs increasing or decreasing in length. Under Feduccia’s version, whales and ichthyosaurs should be impossible.
I don’t think it has to work the way Feduccia thinks – it just needs that secondarily-flightless birds would need to show some signs of their adaptation for flight, and pre-flight dinosaurs have more vestigial signs of of their original adaptation for terrestrial movement still left (and not yet fully erased by their readaptation for flight) – both of which would seem to be “complex adaptations”.
I’m not agreeing with Feduccia, merely suspecting that this point works better against his main argument than for it.
Ah, but that seems to assume that early birds were fully adapted to flight and were not adapted to terrestrial movement. Yet there are plenty of flying birds today that spend most of their time on the ground. Consider pheasants, for example, which rarely fly. There’s no sharp dichotomy here, no adaptation to the ground that would necessarily be absent from a flying ancestor. It’s really difficult at this remove to tell whether a theropod was secondarily flightless. But the phylogenetic position of Microraptor does suggest that other dromaeosaurs might most parsimoniously be considered to be.
I was talking about the adaptation of the forelimbs, rather than how much they use their hindlimbs for walking.
Whether pheasants fly much or not, their wings are able to support them in flight (and so are fully-adapted for flight), and flight is the sole means of locomotion that their wings are now adapted for.
This led to some, perhaps naive and excessive, expectations of what evidence these differences would leave. I suppose the amount of evidence would be less, when losing flight shortly after having gained it (as seems to be the case with dromaeosaurs) than losing it after millions of years (modern flightless birds, particularly non-ratites).
Ah, but theropods were already not using their forelimbs for walking, having been obligate bipeds since the early Triassic. (Interestingly, this would seem to involve another violation of Feduccia’s version of Dollo’s law, since many groups of dinosaurs, including one theropod group, reverted to at least facultative quadrupeds.)
Yes, but I was (perhaps naively) expecting a difference between vestigially-quadrapedal forelimbs and vestigially-flight forelimbs. The former, I would expect to be more ‘forward’ pointing (on a bipedal animal), and the latter more side-pointing. I would also expect closer-to-functional claws on the former.
Naively, yes. Archaeopteryx is pretty much the former.
Not sure to understand your point here, but it seems to me that you’re making the Texas sharpshooter fallacy.
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Indeed I am. Which is why the waiting time problem does too. Gratz, you can see the problem with your argument. Pick a deeply historically contingent adaptation out of an ensemble of alternative histories and calculate the waiting time for it = commit the texas sharpshooter fallacy.
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Do you think that numerous alternative histories may have existed for an historically contingent adaptation ?
Certainly, but the point is broader than that. Rather than estimating the waiting time for wheles, you should be estimating the waiting time for any biological features as interesting as those of whales, including all the ones that didn’t happen.
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That they do exist is an empirically demonstrated fact:
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Which would also require devising a valid way to consistently measure how “interesting” a feature is.
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Well, if it is so easy for new complex biological features to evolve by RV plus NS because they are countless, then it should be trivially easy to rise to Bechly’s challenge of the species pairs. But is it?
From this thread…
Sea otters and ferrets.
Whales
the 'akiapola’au and other Hawaiian honey creepers.
humans and other primates
Bechly’s Challenge fine print rules…
If common descent is acknowledged, they are too similar
If they are not too similar, common descent is denied.
All entries will be sorted into one of these categories by the challenge organizer.
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Yes, such a calculation is certainly impossible.
No, because his challenge is so vaguely worded and unquantified as to be impossible. How many such species pairs should we observe, given the number seen in the fossil record and, presumably, in time-calibrated trees? How do we recognize those species pairs, since no clear criteria have been stated? And why does Bechly explain away the one example he mentions, the human/chimp pair? It seems that any example provided will be rejected for one reason or another, with no way to decide beforehand.
Let’s recall that Bechly apparently accepts common descent at a very deep level, perhaps universal. He’s a God-facilitated saltationist, not a creationist.
Yes. We did. Dogs and countless other domesticated crops and animals. A few centuries of artificial selection, massive morphological change.
Numerous other large-scale phenotypic changes have been observed in laboratory evolution, such as the de novo origin of multicellularity to pick a really obvious one of a radical degree of change. Interestingly there are numerous pathways through which multicellularity can evolve, both depending on what types of species is used in the experiment, and the particular experimental setup and selective pressures employed. Look at the work of William Ratcliff: https://ratclifflab.biosci.gatech.edu/
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None of your examples count for reasons that will become apparent if you ask Gunter Bechly.
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Um, not just easy, but trivially so. And a bit entertaining as well, when it elicits responses from Bechly to the effect that all plants (dicots at least) are for all intents and purposes the same species.
That’s right - if Bechly is going to argue that, for example, tarweeds and Dubautia reticulata have the same body plan (or approach to reproduction, for that matter), he is in essence claiming that all plants are, to use the YEC vernacular, the same created kind. That Bechly has to stoop so low shows that his challenge is cynical (one might say comical), not a serious scholarly argument against evolution.
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Once more: Bechly is not a creationist. He’s a divinely facilitated saltationist.