Friday, April 30, 2010

"A 95 million-year-old fossilized jaw discovered in Texas has been identified as a new genus and species of flying reptile, Aetodactylus halli, says paleontologist Timothy S. Myers, who identified and named Aetodactylus halli. The rare pterosaur -- literally winged lizard -- is also one of the youngest members of the pterosaur family Ornithocheiridae in the world. It’s only the second ornithocheirid ever documented in North America, says Myers, a postdoctoral fellow at Southern Methodist University, Dallas."

Another fossil find. The fossil record is an important part of the reason evolution is considered a fact, not a hypothesis in need of more evidence. There are two aspects to using fossils to document evolution. One is the fossil itself, the things it tells us about the creature captured in stone for us to find millions of years later. The second is the dating of the fossil, to understand when it lived. Since the flow of time allows evolution to play out, we need the date to update the timeline of evolution.

The methods for dating fossils are various, but all are based in solidly established sciences like geology and nuclear physics. Geologists initially received as much grief from the fundamentalists as evolution would later receive. They were estimating the age of mountain ranges, seabeds, and other geologic formations by estimating the time it would take for things like erosion to whittle away at the hards surfaces of the earth. These preliminary estimates quickly placed the history of the earth thousands and even millions of years in the past, well past the six thousand years which the early Bible would indicate.

But this criticism eventually died out. One reason was that the evidence for an old earth continued to mount until there was no reasonable way to claim the earth was actually six thousand years old. Today, some fundamentalists hold onto the idea of a young earth, but they have absolutely no way to support this in the face of such a huge amount of evidence placing the earth approximately 4 billion years old.

When nuclear radiation was discovered and understood, this provided an independent way to test the dates which geology had proposed. The heaviest elements in the universe are often unstable, changing into other elements as they emit protons and neutrons from the nucleus. Some of these take a very long time to decay and so the amount of certain isotopes can lead to estimates of the age of the materials tested. The well-known carbon-14 dating process is just one example. But Carbon-14 is only valid for formerly living material which died no more than about 100 thousand years ago. Other elements, however, can be used to date rocks, sediments, and other parts of the earth's crust. The physics of nuclear decay and half-life determination is highly precise and beyond question as an accurate understanding of the basic building blocks of matter. Radioactive dating allowed more precise determination of the age of various parts of the earth's crust.

Even more confirmation of the earth's age came with the discovery of tectonic plates. Now geologists had a strong theory to explain all the things they had been documenting, such as fossils of fish at the tops of mountains, sections of one continent which fit perfectly into sections of other continents (Africa and S. America, for examle), and the ages of different parts of the crust. There is no question about the validity of plate tectonics. It has allowed us to know roughly how the planet looked at various times in the past. The continent of Antarctica, for example, was once along the equator and covered with tropical plants.

One aspect of plate tectonics which gave further confirmation to evolution was the correlation between when various continents broke apart, and when various species diverged from a common ancestor. Similar mammals exist in South America and Africa, which were once part of the same super continent. The estimates for when certain species diverged corresponds well to when geology says the continents split.

Between the fossil record and continental drift and geology, we can describe the various plants and animals which populated the earth and on which continents they lived and where those continents were and what kind of climate they experienced. This has given us a remarkable ability to "see" the earth as it has existed over the course of its 4 billion years.

When the big picture is seen in this way, it should be clear that no more fossils are needed to prove evolution. New fossils provide only more details allowing us to understand the manner in which evolution has shaped the populations of life on the planet.

For more information, I recommend the following site for a good overview of the evidence for evolution and the place fossils play in understanding evolution:

For a detailed (thought still merely an overview) of transitional fossils, go to this site:

2-million-year-old fossils offer look at human evolution

Not much has been studied of this new fossil discovery, but each new hominid fossil fills in a little more of the evolution of humans from earlier forms of apes. Contrary to popular understanding of human evolution, there is no missing link that would clinch the evidence for human evolution. We don't have anything like a detailed collection of fossils that show every stage of our evolution, but we have enough to show that it happened. This will undoubtedly lead to many new insights into the process.

Wednesday, April 28, 2010

Dinosaurs outgrow their baby feathers

This little article describes a fossil find that demonstrates a transition state between dinosaurs and birds. Critics of evolution often suggest that the fossil record is incomplete and has missing links. This is a bogus argument, however, because the fossil record is expected to be incomplete, not because of any shortcoming of evolution, but for geologic reasons. Fossils only form when an animal is quickly buried in something that excludes the usual chemicals that promote tissue degeneration. The majority of animals and plants that have lived have died in mundane ways that do not lead to fossils.

More significant is the strong evolutionary trends that can be seen in the fossils we have found. The dinosaur to bird transition is just one. New fossils are being unearthed every day and over the centuries that fossils have been collected and studied, nothing in the millions of fossils strongly contradicts the theory of evolution.

Sunday, April 25, 2010

A recent incident in Connecticut illustrates a serious problem in public education in America: the fear of controversy when teaching evolution. A science teacher presented a lesson plan for approval which would compare the accomplishments of Charles Darwin and Abraham Lincoln. The plan was not approved because, according to an e-mail from the principal, the principal did not want to present potentially controversial information to grade school children. An appeal to reverse this decision made to a higher level of the administration was also turned down.

You can read details of the incident here: and

The official excuse was that evolution is “a philosophically unsatisfactory explanation for the diversity of life,” and is “not age appropriate, is not part of our existing curriculum, is not part of the state frameworks at this point in a student’s education, nor a topic in which you [teacher Mark Tangarone] have particular expertise.”

The claim that it was not part of the state frameworks turned out to be false ( The principal and teacher have since resigned and the principal later apologized for his decision.

The anti-evolution extremists have gotten administrators so terrorized that they are afraid to teach evolution. The idea that young children will be traumatized by learning about evolution is propaganda and refusal to teach evolution on this basis will produce the exact result it allegedly tries to avoid. Children are naturally curious and curiosity about human origins is a natural and expected development. When this curiosity is not satisfied with facts that explain the prevailing consensus, they fill the void with whatever other explanation is offered. This is usually the pseudo science of intelligent design or blatantly religious creationism put forward by adults with religious motivations for their ideas and little knowledge of biology. Children grow up accepting these ideas, and when they are later presented with evidence for evolution, they are forced to reject the authorities they've trusted in order to assimilate the information. This leads confused children who complain to their parents, who then complain to the school boards, who respond by watering down text books and "teaching the controversy".

A stand must be taken and school boards need to teach the community, not just the students, about how science works and the preponderance of evidence for evolution. If parents still don't want to face these facts, they are free to home school their children or send them to private schools which cater to their prejudices. Public education needs to stick to the facts and let children know what scientists already know, that evolution is fact, not speculation.
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.