More Surprises for Darwin
It’s not uncommon for theories to have to deal with anomalies, but Darwinism sure seems to get more than its share. Here are some recent examples.
- Fossils lie: Fossils preserve unmistakable clues about past life, right? Not so fast. Nature reported that “Non-random decay of chordate characters causes bias in fossil interpretation.”1 The way early fish decayed before burial could have changed important details about their morphology (this is from the “smelly fish” experiments, 01/30/2010). The decay of traits is non-random and “the more phylogenetically informative are the most labile.” Informative features of the head, in particular, tend to decay faster than the rest of the body. The more the decay, the more the fossil looks “primitive.” It means that fossils can be erroneously placed farther back the evolutionary tree than they should. “Failure to distinguish between the underlying causes of character absence will lead to erroneous evolutionary conclusions.”
The paper warned that the problem could affect interpretations of many groups: “Preliminary data suggest that this decay filter also affects other groups of organisms and that ‘stem-ward slippage’ may be a widespread but currently unrecognized bias in our understanding of the early evolution of a number of phyla.” How come nobody thought of this before?
Derek Briggs commented on this in the same issue of Nature.2 He summed up the problem: “Decay distorts ancestry.” The synopsis: “Experiments with simple chordate animals show how decay may make the resulting fossils seem less evolved. The consequence is to distort evidence of the evolution of the earliest vertebrates and their precursors.” One immediate consequence is that the Cambrian fish found at Chengjiang, China, may actually be more complex than previously assumed. Those famous Cambrian fossils, and those of the Burgess Shale, will have to be re-evaluated in light of the new knowledge. This is big. Fossils might look more primitive than they were. Briggs pointed to this as an illustration of the most general law in science:
Is stem-ward slippage just an isolated palaeontological example of Murphy’s law – in this case, that the most useful evidence is least likely to be preserved – relevant only to early vertebrates? Or is it a more pervasive phenomenon? In general, the answer is that stem-ward slippage is widespread: all fossil animals with a high proportion of missing information tend to fall out near the base of an evolutionary tree through the lack of morphological features (such as structures in the head, in the case of chordates) to ally them with more evolved groups. And the resulting tree may be biased unless the decay sequence is random relative to the tree’s branching order – that is, the order in which characters evolved. As well as prompting caution in interpreting soft-bodied fossils, Sansom and colleagues’ research may turn out to be important in identifying a way to assign confidence limits to the placement of these extinct forms in the tree of life.
- Lilliputians conquered: Speaking of fossils, another interpretation has been falsified. The “Lilliput hypothesis” claims that life shrinks after a mass extinction. This hypothesis has been put to use in the Permian-Triassic extinction, one of the largest in evolutionary history, to explain why gastropods were small after the event. Now, Brayard et al, writing in Geology,3 announced the discovery in Utah of some of the largest gastropods ever found in the early Triassic. “The occurrence of large-sized gastropods less than 2 Ma after the Permian-Triassic mass extinction refutes the Lilliput hypothesis in this clade, at least for the last ~75% of the Early Triassic.” The paper said, “The assumption that Early Triassic gastropods (and other organisms) were generally smaller than during other periods therefore needs more substantiation….” Nothing in the Utah fossil bed suggested unusual conditions that would have contributed to smaller or larger specimens for gastropods or other taxa. And there’s the anomaly. Continuing the Swift metaphor, they said, “Our large specimens from western Utah can be considered as Gullivers compared to most other described Early Triassic gastropods.” See Science Daily for a summary and pictures of the fossils.
- Red Queen murdered: The Red Queen effect, a popular theme in evolutionary literature about continuous variation in response to changing environments, has been tested and found wanting. Michael J. Benton, writing in Nature January 21,4 summarized work by Venditti, Meade and Mark Pagel in the same issue,5 saying, “Biologists have assumed that natural selection shapes larger patterns of evolution through interactions such as competition and predation. These patterns may instead be determined by rare, stochastic speciation.” It is obvious that any re-interpretation of speciation bears directly on theories by Darwin about the origin of species. Now, evolutionists cannot assume that natural selection will act in any predictable away to constant selection pressure. “So, constant speciation rate, and the Red Queen model in general,” Benton explained, “are perhaps better understood as the outcome of rare stochastic events that cause reproductive isolation, rather than a never-ending race in which species are constantly coping with a changing environment.” That sounds closer to the Stuff Happens Law than before.
- The naked chimpanzee: Y-chromosome studies of the chimpanzee genome have revealed a surprise: the chimp Y-chromosome is “remarkably divergent in structure and gene content” (Nature, Jan 28).6 The differences are not only more extensive than predicted; they are clustered in certain hot spots. Science Daily took this not as a falsification of evolution, but evidence that evolution runs super-fast sometimes: “Contrary to a widely held scientific theory that the mammalian Y chromosome is slowly decaying or stagnating, new evidence suggests that in fact the Y is actually evolving quite rapidly through continuous, wholesale renovation.” See a short update on the chimp-human-similarity-meme by Jay Richards on Evolution News & Views. Cornelius Hunter on the blog Darwin’s God considers the “rapid evolution” explanation as an appeal to magic: “we must believe that evolution magically caused rapid changes to occur right where needed to improve function and eventually create a human.” Why, then, did PNAS report on “slow evolution” of the coelacanth genome?7 Why did that fish want to stay virtually unchanged for 150 million years?
- Butterfly spotted: Just-so story alert! An article in PhysOrg is entitled, “How the butterflies got their spots.” The story is of little help to evolution, though: it discusses the conundrum of how two different kinds of butterflies converged on the same wing patterns, down to the same spots, even at the gene level. It’s “one of the most extraordinary examples of mimicry in the natural world.” Chris Jiggins (U of Cambridge) remarked, “It’s interesting because it tells us how flexible evolution is. If you get the same wing pattern evolving independently in different populations, do you expect the same genes to be involved?” The expected Darwinian answer to that rhetorical question seems to be, “No.” Mutations were found, however, to have occurred not randomly throughout the genome, but at certain “genetic hot spots” more subject to variation.
One might have thought this would constitute a falsification of an evolutionary prediction. Jiggins, though, turned the bug into a feature: “This tells us something about the limitations on evolution, and how predictable it is. Our results imply that despite the many thousands of genes in the genome there are only one or two that are useful for changing this colour pattern. It seems like evolution might be concentrated in quite small regions of the genome – or hotspots – while the rest of it does not change very much.” It appears that evolution runs as fast or as slow as needed to keep the theory viable.
1. Sansom, Gabbott and Purnell, “Non-random decay of chordate characters causes bias in fossil interpretation,” Nature 463, 797-800 (11 February 2010); doi:10.1038/nature08745.
2. Derek E. G. Briggs, “Palaeontology: Decay distorts ancestry,” Nature 463, 741-743 (11 February 2010); doi:10.1038/463741a.
3. Brayard et al, “Gastropod evidence against the Early Triassic Lilliput effect,” Geology, v. 38, no. 2, pp. 147-150, doi: 10.1130/G30553.1.
4. Michael J. Benton, “Evolutionary biology: New take on the Red Queen,” Nature 463, 306-307 (21 January 2010); doi:10.1038/463306a.
5. Venditti, Meade, and Pagel, “Phylogenies reveal new interpretation of speciation and the Red Queen,” Nature 463, 349-352 (21 January 2010); doi:10.1038/nature08630.
6. Hughes et al, “Chimpanzee and human Y chromosomes are remarkably divergent in structure and gene content,” Nature 463, 536-539 (28 January 2010); doi:10.1038/nature08700.
7. Amemiya et al, “Complete HOX cluster characterization of the coelacanth provides further evidence for slow evolution of its genome,” Proceedings of the National Academy of Sciences, online before print February 5, 2010, doi: 10.1073/pnas.0914312107.
The first story is especially significant. It means that complex animals could be inferred earlier in the fossil record than previously thought. That muddled trace fossil might actually be the elusive Precambrian rabbit after all. If you don’t accept that, then please explain why you accept anything by people who say that evolution runs super-fast except when it runs slowly, that evolution is predictable except when it isn’t, that evolution is a law of nature except when it is extremely flexible, that mutations are random except when they occur on hotspots, that chimpanzees are 99% similar to humans except when the differences are 70%, that Lilliputians are Gullivers, and that Red Queens are really Court Jesters. When that Precambrian rabbit dove into the fossil hole it was shouting, “Oh dear! Oh dear! I shall be late! to a very important date!” at the Malice in Blunderland party.