http://www.newscientist.com/article/dn13677-evolution-myths-evolution-is-not-predictive.html

Including this nice example:

Perhaps the most striking prediction in biology was made in 1975 by entomologist Richard Alexander. After studying the evolution of eusocial insects such as termites, he predicted that some burrowing rodents in the tropics might have evolved the same eusocial system – as later proved to be the case with the naked mole-rat.

I guess we tend to show evolutionary biology as some sort of proto-science only interested in describing the universe and accumulating tons of data, perhaps because its how biology is born, but anyone who take a look at journals like "evolution" will see evolutionary biologists are very much interested in theory and predictions.

One cannot hope for the sort of quantification one finds in the hard sciences. But if it could be quantified by objective algorithms and applied across the board, I think such postdictions would make up for the impossibility of predictions. There is too much contingency to successfully extrapolate forward; but interpolation ought to be easier.

E.O. Wilson predicted a number of characters that an ancestral ant would have based on the assumption that it shared a common ancestor with wasps. Fossil species Sphecomyrma freyi turns up dating to around the age that was predicted for the divergence of wasps and ants, and it has all of Wilson's characters except for two.

And one from more recent memory:

Neil Shubin opens an old geography textbook and sees there's a bunch of exposed old rocks on Ellesmere Island that no one has ever searched before. They're rocks in which, according to evolutionary theory, we're likely to find "fishapods"–they date to the age when fish first moved out onto the land. He decides to go on a dig. All hail Tiktaalik.

Yes, in the sense that you can make detailed predictions only for simple situations. You can only make predictions in broad strokes for complex situations.

In physics, predicting the motion of just three idealized interacting bodies was fiendishly difficult (cf. "three body problem").

If classic Newtonian physics has a hard time predicting three simple objects following strict, simple rules, image the difficulty of making detailed predictions involving millions of entities following probabilistic rules. In other words, biology.

Biological prediction is far from hopeless, though. For instance, companies now anticipate that antibiotics or pesticides will lose their effectiveness as control agents after several years, due to the strong selection pressure for resistance that the chemicals apply to the "bugs" they are meant to control.

That said, I think there is still confusion regarding "fact" vs. "theory" vs. "path". My post was about predictions based on assuming the fact of common descent. I think predictions about path in a major sense are simply not possible given the number of influences. However, the notion that the theory can't make predictions is clearly incorrect, given that there are mathematical models specifically developed to predict the effects of natural selection, drift, gene flow, etc., within populations, and these can be and have been investigated experimentally and through observation of natural systems.

To a physicist, a lot of those predictions may seem a little thin, and broad enough to be fulfilled in a great many ways. I think what some folks may mean by "predictions of evolution" is in Dr. Gregory's second layer: the theory. For example, Newton's theory of gravitation enabled him to predict planetary positions and motions with great precision (if after laborious calculations). In that spirit, Darwin's theory of natural selection via the struggle for existence ought to enable us to "calculate" the "trajectory" of species in some way. (I know there are no Darwin's Equations. The language is analogical.)

The dog-bear seems to be more or less ancestral to dogs and to bears (arising in two distinct habitats over the ancestor's range), possibly a "collateral" ancestor. Given the dog-bear, can we predict the dog and the bear? IOW, does natural selection predict forward the way mechanics or electromagnetism does?

Just to be clear: Species either poof into existence or they emerge from other species; and they don't poof. Therefore, they emerge from other species. So the fact of evolution [Level 1] is quite solid. The question is whether the theory/mechanism [Level 2] makes adequate predictions of the path [Level 3]. I don't expect evolutionary theory to be any more immutable than gravitational theory, after all, and sometimes it's useful to know at what points the theory breaks. [E.g., Newtonian mechanics at the very small and the very fast.]

CONFIRMED TODAY!

I appreciate your interest, and given the polite tone you have taken and your apparent sincerity in contemplating the subject, I am happy to carry on in the discussion.

I think it would be productive to separate "evolution" into its three major components or definitions.

One, the "fact" of evolution. This is the idea that species are related through common ancestors by descent with modification. This is considered a "fact" in the scientific sense that it is supported by a wide range of independent types of evidence.

Two, the "theory" of evolution. This is the series of mechanisms that have been put forth to explain the fact of evolution. This includes mutation, natural selection, genetic drift, gene flow, and other components.

Three, the "path" of evolution. This is the historical route that lineages have followed over time. This would also cover patterns like whether evolution has occurred gradually or in bursts.

It is important not to mix these. "Punctuated evolution" would be about the path, and perhaps would raise questions about the mechanism, but it has no bearing on the fact. (And, for the record, I am a proponent of punctuated evolution as a common phenomenon).

As to your specific statements,

1) You may be expecting a very gradual change depicted in the fossil record, which is almost certainly impossible to find. Fossils are rare in most groups. For vertebrates, we have examples showing the major intermediate stages (but note a difference between lineal and collateral ancestors), but not change in minute steps. However, in some invertebrates or protists that leave hard cases, the record can be remarkably detailed.

2) Banding is based on the arrangement of DNA, specifically whether it is compacted (heterochromatin) or less so (euchromatin). This is quite different from whether the DNA sequences are the same. So, the observation is a discrepancy in chromosome number, which was proposed to be explained by chromosome fusion and supported initially by banding data. Then, when genome sequences were available, it was possible to confirm not only that a fusion occurred, but to identify the exact site of it.

As to paleopolyploidy, no, a chromosome fusion would not be part of that. Paleopolyploidy under Ohno's hypothesis is that entire genomes duplicated 2 or 3 times in the history of vertebrates/bony fishes. A fusion of chromosomes is a different process.

5) You're right that there aren't enough specimens to be sure about the overall range of Neanderthals (new discoveries have expanded it), but it is pretty clear that they did not originate in Africa. Nor are they ancestors of ours, rather they would be cousins. We now have DNA from Neanderthal fossils, so we can be sure that they were very closely related.

Recently, actually, yesterday, at the library I obtained Only A Theory – Kenneth R. Miller and The Edge of Evolution – Michael J. Behe, to do a compare and contrast.

First impressions

My name is Kenneth R. Miller. I am very important because I teach at Brown University and have been on lots of committees. I just don’t teach any class at Brown, I teach Cell 4. I have also published a high school text book on biology. Although I teach cell biology I sometimes have problems getting to the point. I like to quote Mathew Arnold, Disraeli, and others because it makes me seem more well rounded and well, intelligent.

Miller may eventually make some good points but his beginning is awkward.

Behe to his credit gets to the point in the 2nd paragraph –

“-it is a mixture of several unrelated, entirely separate ideas. The three most important ideas to keep straight from the start are random mutation, natural selection, and common descent.”

I have not thought about it enough to decide for myself if the ideas are entirely separate but his plain statement of the troika of the neo evolutionary synthesis is seminal.

1. With more detail provided I appreciate your point. However, this could also support a punctuated evolutionary scenario. Most impressed that the time period predicted was correct. There are many cases of newer time studies finding more recent times for many events.

2. I am extremely interested in the 24 to 23 transition. Is this an example of Ohno’s Paleopolyploidy Hypothesis? They looked and saw banding and then predicted that if they looked closer they would still find banding. Wow!

In general I am unopposed to common descent. My concern here is if whether there was enough time, based on the geological record, for this change to have happened by random mutation? In the spirit of Ohno’s Hypothesis, there seems to be many times when very large changes happened over relatively short time spans.

3. OK

4. OK

5. Thanks for the Neanderthal correction. Still, there is a lot being deduced from a relatively small sample size.

I think the neo evolutionary synthesis is a good theory, but still a theory. My concern is that participants in this field are becoming increasingly myopic. More succinctly, nothing I am aware of prevents occasional periods of punctuated evolution. The mystery being the causes of these unpredicted events.

Life is good,

d