EVOLUTION
In the February issue of Natural History, Stephen J. Gould talks about space which is the theme of the issue. However, he begins the article by talking about evolution. Remember that Charles Darwin never used that word in his Origin of Species, but called it "descent with modification". Why is that? Because the definition of the word means an unrolling or unfolding in time of a predictable sequence of events. It implies direction and preset events, which actually may be true when referring to space. Stellar "evolution" does follow a predictable sequence of changes because of very specific physical laws. But organisms adapt to local circumstances and these vary in a random manner and can not be predicted. So in the strictest sense of the word, it is not appropriate to describe descent with modification as evolution. However, over time it seems to have "evolved" into a definition for biological change through time.
Stephen also talked about two recent events and their impact on our understanding of evolution. The first I mentioned in an earlier column. That is the discovery of two vertebrate genera in the Lower Cambrian in China. This means that all animals’ forebears appeared in the Cambrian and that the line that leads to us primates did not evolve later and stand higher than the others. The second discovery involves gene sequencing of parasites. Using that techniques scientists can now show that some parasites are actually simplified forms of more complex animals rather than the maintenance of an original primitive state. A higher Hox gene has been found in them indicating that the parasites have become simplified in anatomy by adaptation to their parasitic lifestyle. This strengthens the argument that biological evolution is not directional in leading to more complex structures. We know that because of the physical laws our sun will self destruct in about 5 billion years, and it is possible that the only ones left on earth to see it will be the indestructible bacteria!!
MORE EVOLUTION
In two recent studies reported in Science, scientists report that natural selection appears to be as important as Darwin thought. One reported a change in the size of the wings of European fruit flies. When these flies were introduced from Europe to California, it was noticed that the wings got larger from south to north (exactly as they had in Europe). They also noted that the European flies increased the size of their wings in the part closest to the body, while those in the US increased the size on the outer part of the wing. However, they both adapted to create a larger wing. The other study was of stickleback fish in three isolated lakes in British Columbia. The same two species were found in all three lakes; one was a hefty bottom dwelling fish and the other was a smaller streamlined open water feeder. The two do not interbreed. When mixed, the females chose only fish of their own type regardless of their lake origin. The researchers believe that this strengthens Darwin’s case.
BIRD-DINOSAUR FOSSIL PROBLEM
It was bound to happen sooner or later. With all the exciting well preserved fossils coming out of China these days, it was only a matter of time before there would be problems. It is extremely important to carefully excavate and document all important fossils. However, it is also true that fossils have increased in monetary value a great deal recently. Because of this the famous fossil of Archaeoraptor reported in National Geographic recently has been shown to be constructed of two different animals. The Czerkas purchased the fossil at the Tucson Show thinking it was authentic. Now they have found that the tail is the companion piece to another fossil in a collection in China. And that animal is a dinosaur. The top part of the fossil is that of a bird. Another issue raised was about National Geographic jumping the gun and publishing the info before a scientific study of the fossil had been done. There is a lot of that going on now as everyone wants to be the first to report these exciting new animals. It always takes a while for the true scientific study to come out and some are impatient. Perhaps, this incident will slow things down a bit.
SUE UNVEILED
At this time, it appears as if everyone in the world will have an opportunity to see The Field Museum's SUE unveiled on May 17, 2000. Current plans call for the presentation to occur on the early morning TV shows at about 6:50 am CST. CNN will also be there to broadcast it all over. The Museum will open as usual at 9:00 am for the public and we are expecting big crowds. Until the unveiling there will be a big box in Stanley Field Hall where SUE will be erected. A curtain will cover the top as well so no one can see until May 17. There are no SUE bones at the Museum these days as they are away being mounted and will be in the box when they return. However, there is still prep work being done in the McDonalds Lab at the Museum. They are working on some dinosaurs from Canada and from Madagascar as well as other animals like fish.
DINOS ???
There are a lot of new discoveries being talked about these days. I already mentioned a couple- the monster sauropod from Texas and Santanaraptor from Brazil. However, they have yet to be officially documented. And now there is another one – a feathered T rex from Montana. Bob Bakker is involved with this one which he describes as a sleek version of the beast. On all of these and others, I will withhold more until the official technical information is reported. They are all very exciting, but the early information on such finds is often wrong. For example, a lot of the early information on SUE is now known to be wrong and everyone will know that when the official paper comes out with the actual information. It is fun to hear about them, but it makes sense to wait for full documentation.
Karen Nordquist, ESCONI Paleontology Study Group
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