Some context for those quotes would be in order; words and phrases -- even entire sentences -- can have different meanings in different contexts (think, e.g. of the supposed contradiction between James' assertion that Abraham was justified by works and Paul's statement that he was justified by faith; this contradiction disappears when both are read in context and we see that they are using the word "works" in different ways).
Steven J. Thompson
June 30th, 2012 17:28
The idea that birds are modified archosaurs (that their closest living relatives are crocodilians) is almost a century and a half old, and is still unchanged. Even the idea that birds are descended from theropods is over a century old, though I suppose it's only been considered a settled point for "a few years." That Dimetrodon was more closely related to modern mammals than to lizards or dinosaurs, that all these groups are more closely related to lungfish than lungfish are to trout or bass, again, is an idea that's been around for decades now. Even the idea that humans are more closely related to chimpanzees than gorillas has been pretty much settled science for nearly 40 years now, which is more than most people would consider "a few years" (and the idea that we are closely related to apes is, of course, several decades older yet). I suppose the point of the quote is that relationships among orders within classes (e.g. how even-toed hoofed animals are related to odd-toed hoofed animals) has been very speculative until recent years when genetic data could be brought to bear on the question. Many questions about relationships that could not be settled on the basis of comparative anatomy yield to data from comparative genomics.
Steven J. Thompson
June 30th, 2012 17:32
The claim that "the whole idea of a gradualist tree is wrong" could be taken many ways. I don't think it's a claim that the basic idea of a "tree of life," a family tree in which very different species are related through descent from common ancestors, is false. Since "gradualist" (an adjective not commonly used to describe trees, even metaphorical ones) is used, perhaps the point is that species don't change at a constant slow rate over their entire range, but give rise to new species during brief (hundreds to thousands of years) of relatively rapid evolution in isolated populations. But without a context, many other interpretations are possible: perhaps the author is referring to the fact that the roots of the evolutionary tree are tangled: among single-celled prokaryotes, lineages did not merely split, but sometimes merged (our mitochondria, for example, appear to be descendants of symbiotic bacteria than lodged in ancestral cells).
Steven J. Thompson
June 30th, 2012 17:38
"We need to rethink the process of evolution itself." Well, perhaps we do; again, you provide no context, much less reasons why evolutionary theory needs to be "re-thought." But I very strongly suspect that "the process of evolution" here is distinct from "evolution" itself; the author is saying that we need to re-think how evolution has occurred, not whether it has occurred. As to what needs to be re-thought, again, one can't tell from a "prooftext" out of context. Perhaps, again, the author is simply talking about the overrated dispute between "punctuated equilibrium" (species arise through relatively fast but still gradual -- no "one species lays an egg and another species hatches out of it" -- evolution in isolated populations) versus "phyletic gradualism" (species change constantly, very slowly, across their entire range). Perhaps the author thinks we need to put more emphasis on some aspect of evolution -- endosymbiosis, epigenetics, etc. -- than has previously been done. The entire field of evolutionary biology wouldn't exist unless biologists agreed that there is still much to learn about the processes of evolution.
Steven J. Thompson
June 30th, 2012 17:45
It seems very strange that anyone would say that the one rule that evolutionary biologists thought they could cling to was that complexity always increased (of course, it seems even stranger to connect this "rule" to problems in phylogeny -- figuring out what was descended from what). Anyone who's ever heard of "vestigial organs" can tell you that complexity can be lost in the course of evolution as well as gained. Whales lost hind limbs; snakes lost all limbs. Birds lost distinct clawed fingers on their forelimbs (not to mention teeth). Many parasites have drastically stripped-down digestive systems and other organs compared to their free-living relatives and ancestors. This is very basic stuff. Now, evolutionists have argued over whether complexity tends to increase over time ("tends," rather than "always does"), with Stephen J. Gould arguing that there was no such tendency while Robert Wright tended to argue the opposite -- but the existence of such an argument implies that there was no well-established "rule" that one could cling to. So this quote strikes me as simply bad writing or misinformed.
Steven J. Thompson
June 30th, 2012 17:51
"Some evolutionary biologists now suggest that loss ... is the key to understanding evolution." As always, it would be interesting to learn what originally filled that ellipsis. I really don't trust ellipses in quotes provided by creationists. But as I noted upthread, yes, loss of traits and functions has been recognized as part of evolution since the beginning (e.g. flightless beetles and birds, embryonic baleen whales that grow, then resorb, teeth and hind limb buds, etc.). For that matter, one possible way for "irreducible complexity" (as defined by Michael Behe) to evolve is to start with a reducibly complex system (i.e. one that will still work, even if less well, if you take a part out), and have some of the parts lose part of their function (so that they can no longer take up the slack for a missing part) and/or simply delete redundant parts. Likewise, sexual reproduction started out among organisms that could also reproduce asexually, though some of their sexually-reproducing descendants lost that ability and came to rely exclusively on sex to make babies. So there are many aspects of evolution that can only be understood in terms of loss; without further context it is not clear why some biologists think that this is true of evolution as a whole.
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