Sunday, April 25, 2010

I have not had the time to update this as I intended. The point of this blog was to show how commonly the theory of evolution explains the details of the diversity of life on earth. As a scientist, I'm aware of the role of evidence in developing theories. Everyone who examines the evidence for evolution with an open mind should be impressed by how thoroughly they theory explains the living world. The fact that so many doubt the theory indicates how poor a job our education system does of presenting this evidence.

I have been casting about in my mind for an analogy that does justice to the mountain of evidence for evolution placed next to the feeble examples presented by the anti-evolution scientists of what they think are features of life which could not have evolved. I think I've got something that may begin to hint at this difference.

Imagine the following hypothetical situation. The Pope is giving his annual Easter address to the assembled masses in St. Peter's Square. Film crews line the outer perimeter. In the midst of the address, a man pulls a rocket propelled grenade launcher from hiding and fires at the balcony where the Pope is speaking. Miraculously (some will say) the rocket misses the balcony and the Pope is not injured. The man attempts to load another grenade but is wrestled to the ground and apprehended by security forces.

A trial is held for the man on charges of attempted murder of the Pope. The evidence supporting the charges is massive. The event was witnessed by millions of people. Thousands of these people had digital cameras with which they documented the event from all sides. News media from countries around the world captured the events on high quality video equipment. The rocket launcher had his fingerprints on it. When authorities searched his house, they found evidence that he bought the weapon and stored it at his house. They also found detailed notes in his handwriting explaining how he planned to assassinate the Pope. In addition, the man readily confessed to the attempt.

Despite all this evidence, imagine that a small group of people maintains that the man is innocent. They don't have an alternative suspect. In support of the their claim, they point out that some of the pictures taken of the incident in St. Peter's Square do not clearly show the man's face. The say that the material in his house could have been planted, although they have no idea who that might be or why they would do that. Finally, they quote the man's mother as saying that she did not believe her boy was capable of such an act.

When the weakness of their "evidence" is pointed out, they have no rebuttals except to claim that the authorities are prejudiced against the man and are conspiring to frame the man.

The evidence for evolution is everywhere. First of all, the mechanism of evolution is not hypothetical but real and easily explained and demonstrated. Biological reproduction relies on the genetic material to accurately guide every organism into a close replica of the parents. Some variation in the particular genetic code is naturally present. Individuals with traits that hinder their survival will make them statistically less likely to pass on their genetic code to offspring, while individuals with traits that enhance their survival have an increased chance of passing on their genes. With thousands, millions, even billions of generations over which the statistics can operate, evolution is inevitable.

There is the fossil record showing the progression of traits. While some of the record is understandably incomplete (fossils only form in certain geological conditions), there are many examples of detailed step-by-step evidence of evolution, such as the horse, the transition from reptile to mammal, from reptile to bird, and fish to amphibian, to name but the most dramatic.

There is the close match between the family trees generated by the fossil record and trees suggested by the degree of genetic difference between modern species and the length of time since various differences occurred. The variation in species also follows predicable lines when we examine species from different island and continents separated by oceans, such as Australia, Madagascar, North and South America. Similar environments have produced similar species, such as the dingo on Australia and the wild dogs of the rest of the world.

Then there is the evidence in vestigial organs and bones, such as the hip joints in snakes and eye sockets in blind-from-birth moles. There is also plenty of evidence of evolution happening in the past two hundred years, including laboratory tests on species such as fruit flies and bacteria. There is the example of domesticated animal breeding which shows just how widely a given species can diverge just by the power of selective breeding.

There is the close fit between the evidence for evolution and the other sciences which demonstrate key features of the evolutionary theory, such as the age of the earth (geology), the age of the sun (astrophysics) and the age of the universe (particle physics). There is evidence from such sciences as anthropology, archaeology, and paleontology showing the evolution of the human species over millions of years. There is evidence of cultural evolution, evolution of ethics (cooperation), evolution of language, writing, and many other technical arts.

Finally, the big picture of the universe from the time of the Big Bang shows various kinds of evolution in the sense of simpler things combining to form more complex systems which in turn generate more complex systems. In the beginning was energy that evolved as it cooled to form protons, neutrons, and electrons, which combined to form hydrogen and helium, which combined at the hearts of stars to form larger elements, with the heaviest elements forming in super nova explosions of stars. Elements combined into planets that evolved complex compounds from the basic elements. Some of these compounds formed complex self-replicating forms, and life was off and running. Over time, single cells evolved cooperatives which formed multi-celled organisms. Groups of organisms combined over time to form even more complex organisms, such as fish and plants. In some of these, family groups evolved into simple societies and some of these evolved into complex societies of cooperating individuals. One of these evolved intelligence and once that reached a certain level, evolution of culture and technology followed.

So the amount of evidence is truly a mountain range, while the best the anti-evolutionists can offer are a few feeble aspects of a few organisms which they say could not have evolved. They offer a religious text from 3 or 4 thousand years ago which gives us a creation myth, the details of which do not even closely resemble the picture developed by modern science. They offer egotistical indignation that we humans could have evolved from more lowly forms. They offer no alternative to explain what evolution can explain. Their most basic argument is flawed with the logical error that attempts to prove one theory by showing that the prevailing theory is not adequate. Even if evolution were wrong, it would not support the creationist/intelligent design alternative the anti-evolutions espouse.

So please don't let anti-evolutionists determine what gets taught in public schools. Children need to know the facts in order to judge the facts. The evidence is overwhelming. People uncomfortable with the consequences must deal with this rather than try to hide the mountain with a religious myth.


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