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As previously mentioned Nature published on a couple of transitional flatfishes. The National Geographic uses this as a chance to take a dig at the Discovery Institute. Casey Luskin (a lawyer, not a biologist) is outraged I tell you, outraged that the NG suggests that Intelligent Design is really creationism. No dear, it is. The reason you refuse to answer questions about the nature of the designer is that as soon as you did you'd be outed as a bunch of Creationists who won't even answer questions about how old you think the Earth is.
In fairness to Luskin the NG doesn't actually quote anyone who identifies themselves as cdesign proponentsists. However Luskin then goes off on one about how the NG says that sudden evolutionary changes are inconsistent with gradualistic evolution, but are what we see in the fossil record. Unfortunately the debates between Punctuated Equilibria and more gradualistic interpretations of evolution are rather more involved than either NG or Luskin seem to realise. What often happens when an evolutionary novelty appears is that you get a rapid radiation of all sorts of interesting organisms doing different things, and eventually things settle down, and some lineages die out. The spottiness of the fossil record, and the discontinuities of sediment deposition being what they are, for us to see gradualistic change you need rather rare circumstances and lots of fossils. Trilobites are a good example, showing both "Punc Eq" and gradualistic changes.
Of course this ignores the "one man's gradualism is another man's Punc Eq"- neontologists would say that 60,000 years is a very long time, but a palaeontologist might not see a gap twice as long as this in a stratigraphic column. Then there's Dawkins' argument that Gould wasn't actually saying anything new (there are passages in Darwin's work pointing out that rates of evolution are not constant).
Luskin then goes on to criticise the actual paper itself. Unfortunately I'm not sure he's read it. (I have, its really rather good- if short, and generally very clear.) Heteronectes and Amphistium are transitional. The eyes are not on the same side of the head as in modern derived forms, but the whole head is asymmetric. Some modern flatfish have one eye on the "top" of the skull and one in the usual place. So we have a transition. "Normal" fish-->Heteronectes/Amphistium (asymmetric skulls)-->Spiny Turbot (one eye on top)-->Derived flatfish.
There are derived flatfish that are contemporaries of these two genera. Luskin (and predictably the conventional creationists) then use a variant of the "why are there still monkeys" non-argument, and Luskin proposes his own hypothesis, that the two genera are actually going the other way, and are derived from normal flatfish. The little cladogram that Friedman includes in the paper immediately disproves that one. In fact if he'd found that these fishes nested deep within the flatfishes it would be bigger news, because it would mean that we really don't understand flatfish evolution- rather than the fact that we had a fairly good idea what must have happened, but didn't have the fossils to demonstrate it.
The paper finally mentions that:
In fairness to Luskin the NG doesn't actually quote anyone who identifies themselves as cdesign proponentsists. However Luskin then goes off on one about how the NG says that sudden evolutionary changes are inconsistent with gradualistic evolution, but are what we see in the fossil record. Unfortunately the debates between Punctuated Equilibria and more gradualistic interpretations of evolution are rather more involved than either NG or Luskin seem to realise. What often happens when an evolutionary novelty appears is that you get a rapid radiation of all sorts of interesting organisms doing different things, and eventually things settle down, and some lineages die out. The spottiness of the fossil record, and the discontinuities of sediment deposition being what they are, for us to see gradualistic change you need rather rare circumstances and lots of fossils. Trilobites are a good example, showing both "Punc Eq" and gradualistic changes.
Of course this ignores the "one man's gradualism is another man's Punc Eq"- neontologists would say that 60,000 years is a very long time, but a palaeontologist might not see a gap twice as long as this in a stratigraphic column. Then there's Dawkins' argument that Gould wasn't actually saying anything new (there are passages in Darwin's work pointing out that rates of evolution are not constant).
Luskin then goes on to criticise the actual paper itself. Unfortunately I'm not sure he's read it. (I have, its really rather good- if short, and generally very clear.) Heteronectes and Amphistium are transitional. The eyes are not on the same side of the head as in modern derived forms, but the whole head is asymmetric. Some modern flatfish have one eye on the "top" of the skull and one in the usual place. So we have a transition. "Normal" fish-->Heteronectes/Amphistium (asymmetric skulls)-->Spiny Turbot (one eye on top)-->Derived flatfish.
There are derived flatfish that are contemporaries of these two genera. Luskin (and predictably the conventional creationists) then use a variant of the "why are there still monkeys" non-argument, and Luskin proposes his own hypothesis, that the two genera are actually going the other way, and are derived from normal flatfish. The little cladogram that Friedman includes in the paper immediately disproves that one. In fact if he'd found that these fishes nested deep within the flatfishes it would be bigger news, because it would mean that we really don't understand flatfish evolution- rather than the fact that we had a fairly good idea what must have happened, but didn't have the fossils to demonstrate it.
The paper finally mentions that:
"The sudden appearance of anatomically modern pleuronectiform groups in the Palaeogene period matches the pattern repeated by many acanthomorph clades. Inferring interrelationships between higher groups in this explosive radiation has proved difficult, and an unresolved bush persists."This is of course seized on by Luskin as an admission that the evidence for evolution is weak, and Friedman has overstated his case. Er no it isn't. Its pointing out that while we now have a nice little evolutionary sequence for one particular group of fishes, there are still unresolved questions about fish evolution. What these fossils have not revealed (yet) is how the flatfishes fit within this wider group of fishes. The Tree of life page for the Percomorpha (the group in question) shows what Friedman means by a bush. Everything is mushed together what is called a "polytomy", and it isn't at all clear what the relationships between the various groups are.
