Evidence for Evolution

2010-05-15T08:30:00.004-04:00

Study of Evolution Needed to Understand and Control Plant Diseases, Scientists Argue

A strong argument for the validity of evolution is the fact that our research into diseases and medical treatments assumes that evolution accounts for the divergence of both organisms such as ourselves and disease pathogens. Without this assumption, our medical research would grind to a halt.

An article in Red Orbit, an Internet journal for news on science, space, and technology, Emergence Of Fungal Plant Diseases Linked To Ecological Speciation, discusses the reasoning behind a commentary published by Tatiana Giraud, Pierre Gladieux, and Sergey Gavrilets that argues for the need for funding for general research on evolution. Without understanding evolution, they argue, we would not be able to understand how new diseases emerge, since a new species may provide a new and better host for certain portions of a pathogen community. Pathogens themselves also tend to evolve rapidly.

So when we hobble efforts to teach evolution, we are undercutting the ability of our society to generate scientists capable of studying the one group of nature's organisms which still poses a serious threat to human life. Anti-evolutionary crusaders are also the loudest voices for cutting government and private funding of evolutionary research. A citizenry unaware of the value of understanding evolution will be less likely to object when funding for evolution is cut.

So the next time you come down with a disease and the good doctors at your local hospital quickly identify and treat your disease, say a prayer of thanks for the scientists who have devoted their lives over the past 15o years understanding the nature of evolution! Then next time you hear someone suggest we cut funding for evolution research, ask him or her how Intelligent Design advocates would approach the control of infectious diseases.

This leads me to think about the theology of Creationism and Intelligent Design, which would have us believe that all the diversity of species is purely the result of recent creation of all species by God. Ian Anderson, the driving creative force behind the rock group Jethro Tull, wrote a lyric that goes, "The jungles are full of crocodile nasties/ and he who made kittens put snakes in the grass."

The comedy group Monty Python wrote a parody of the song "All Things Bright and Beautiful," called "All Things Dull and Ugly." Here are the lyrics of the original song (which I remember singing in my church's children's choir):

Refrain:
All things bright and beautiful,
All creatures great and small,
All things wise and wonderful:
The Lord God made them all.

Each little flow’r that opens,
Each little bird that sings,
He made their glowing colors,
He made their tiny wings.

The purple-headed mountains,
The river running by,
The sunset and the morning
That brightens up the sky.

The cold wind in the winter,
The pleasant summer sun,
The ripe fruits in the garden,
He made them every one.

The tall trees in the greenwood,
The meadows where we play,
The rushes by the water,
To gather every day.

He gave us eyes to see them,
And lips that we might tell
How great is God Almighty,
Who has made all things well.

Here is Monty Python's version:

All things dull and ugly,
All creatures short and squat,
All things rude and nasty,
The Lord God made the lot.

Each little snake that poisons,
Each little wasp that stings,
He made their brutish venom.
He made their horrid wings.

All things sick and cancerous,
All evil great and small,
All things foul and dangerous,
The Lord God made them all.

Each nasty little hornet,
Each beastly little squid--
Who made the spiky urchin?
Who made the sharks? He did!

All things scabbed and ulcerous,
All pox both great and small,
Putrid, foul and gangrenous,
The Lord God made them all.

In theological circles, these songs highlight the problem of theodicy, the name given to the question, "If God is a loving God, why do we have such a multitude of evils in the world?" A theology that embraces the findings of science has no need of this question. The evolution of all the things we value most, including ourselves, strawberries, bluebirds, ladybugs, goldfish, and kittens, also produced all the nasty, ugly parts of nature. In Unitarian Universalism, this is referred to as the interconnectedness of all life. Embracing this leads in a very different theological direction than a Creationist theology.

It also means that when we study evolution, we are studying life, ourselves, and--I would assert--God. Other religions, such as Buddhism and Taoism, also embrace the plurality of nature, pointing out that the distinctions between good and bad, beautiful and ugly, medicine and poison, are human inventions, not a part of the natural order. The sooner we recognize this, the more quickly we can approach an understanding of the whole which is both wholesome and healthy.

2010-05-13T05:04:00.007-04:00

Filling in the Gaps

Anti-evolutionists will not be trumpeting this news to their faithful fundies, I don't think. Irish study fills gap in evolution describes a new fossil find, not just a single fossil, but a site that is providing thousands of fossils documenting a stretch early evolution that has not been studied before. As the article reports, fossils of soft-bodied animals are extremely rare. This is because the conditions that will preserve a soft body are extremely rare. Only when the soft bodies are captured in some kind of muck which stops decay and then the muck turns into something like shale do we get to see what these ancient creatures looked like.

Those critical of evolution like to claim that the fossil record is incomplete. They say that as if it were not completely expected and explainable. As described in my previous post, the fossil record shows steady, slow evolution of many species, as well as relatively fast spurts of evolution. What gaps exist are not because intermediate creatures did not exist, but because they were not preserved in fossils or because we have yet to discover where they are preserved.

When new fossils are found, they provide a kind of lab in which to test evolutionary theory (not that more tests are needed, but that is what science always does with new information). We look at what we find and ask if it is consistent with theory. In this case, the fossils found in Morocco show life about 480 million years ago. Another site preserving such soft-bodied species dates back 510 million years ago. If evolution is correct we expect to find some creatures essentially unchanged even over 30 million years. But we also expect some creatures to have evolved to take advantage of new ecological niches.

That is exactly what is being found in the Fezouata Formations in the Draa Valley north of Zagora in southeastern Morocco.

“We know the fossil record is an important record of life, but it is an incomplete record,” says [Dr. Patrick] Orr. It makes interpretation of the progress of evolution very difficult, akin to trying to assemble the plot of a film using only intermittent still images, he suggests.
There was an explosion of new life forms during the Cambrian Period, with the shales revealing soft-bodied animals, according to Orr, “and then the record went blank.”
Now the evolutionary story continues with the Moroccan fossils showing that many of these Cambrian animals survived and multiplied into the next period, the Ordovician. The original animals were there but the Ordovician Period saw a rapid diversification of related species and so the mix is much more varied, Orr says.

This kind of filling in of gaps has been going on since scientists began hunting for fossils. Sometimes a new fossil location forces revision of the story that scientists had developed based on the then existing evidence. But this is a natural part of science. Such revisions are not to the theory of evolution, but to the details of what we are understanding evolution to have entailed.

2010-04-30T21:41:00.005-04:00

Rare 95 Million-Year-Old Flying Reptile Aetodactylus Halli Is New Pterosaur Genus, Species

"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: http://evolution.berkeley.edu/evolibrary/home.php

For a detailed (thought still merely an overview) of transitional fossils, go to this site: http://www.talkorigins.org/faqs/faq-transitional.html

2010-04-30T20:17:00.002-04:00

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.

2010-04-28T19:21:00.002-04:00

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.

2010-04-25T12:18:00.003-04:00

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: http://www.wired.com/wiredscience/2010/04/evolution-controversy/ and http://www.acorn-online.com/joomla15/thewestonforum/news/local/56145-evolution-flap-ribbens-apologizes-weston-parents-have-questions.html.

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 (http://is.gd/bDLT3). 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.

2010-04-25T09:35:00.004-04:00

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.

2009-03-08T10:02:00.004-04:00

When I started this blog, my goal was to provide support for the theory of evolution by demonstrating that, contrary to statements by anti-evolutionists, new evidence of evolution is continually being reported. This includes new findings from fields such as cell biology, ecology, morphology (the study of the forms organisms take), ethology (the study of animal behavior), medicine, and neurology. Oh, and let's not forget fossils, which continue to turn up new examples of intermediate forms. Time has not allowed me to carry through with this agenda.

But there is an argument that needs to be made that relates to the question of evidence and evolution. Anti-evolutionists, who with a few exceptions are not biological scientists, claim that current text books and biology curiculla need to reflect an alleged abundance of evidence that calls evolution into serious question. Now this "evidence" has been refuted by competent scientists, but the idea that such evidence could exist is refuted by a proper understanding of the way science works.

If the evidence existed which seriously challenges evolution, and if biological science is operating by the same rules as other sciences, then it would be leading biological scientists who would be insisting on debate about the validity of the theory. Scientists make their mark on the history of science by seeking out such evidence as cannot be explained with current theories. That is what science does. Yet no such fight is being fought, at least not by scientists.

A good example of how this works can be seen in the history of phyics around the turn of the 20th Century. A famous anecdote illustrates the attitude of established physicists at this time. A recent college graduate asked a physics professor if he recommended a student seek an advanced degree in physics. The professor discouraged the student, saying that all the important theories had been established and the only work that remained for physicists was to calculate the known constants to greater and greater accuracy. One student at the time, who thankfully did not receive and follow that advice, was Albert Einstein. In 1905, working as a patent clerk, published papers that exploded the complancy of physicists and established whole new fields of study, such as relativity and quantum mechanics.

How did the scientists of the day respond? Did they ignore this evidence, attempt to cover it up, try to stiffle criticism of the established theories? No. Physicists were energized and zestfully set to work to find the theory that would explain the evidence coming to light better than the established theories. This is not to say that every physicist of the day was persuaded that new theories were needed. In some ways, the new theories did not really take off until the old theorists died off and were replaced by students who did not have any emotional stake in maintaining the status quo.

This is how the system is supposed to work. Science invites the reporting of evidence that calls theories into question. It thrives on them. If the new theories proposed by physicists such as Einstein, Bohr, Heisenberg, and others did not explain the evidence in hand better than the established theories, no changes would have been made. Science is inately conservative, requiring a lot of evidence before changing its collective mind.

My point is that if the evidence that seriously challenged evolution existed, we would not need non-scientists to lead the charge to change the acceptance of evolution in the scientific community or the lay community. The scientists themselves would be fighting over whose theories would replace evolution. No such fight has ever occured in the case of evolution. Most of the evidence that seemed to call evolution into question has turned out to be improperly interpreted. Sometimes later discoveries shed new light on the evidence.

For example, some anti-evolutionists have made much of a bed of rock with fossil footprints that appeared to show footprints of humans along-side footprints of dinosaurs. If this were good evidence, it would indeed throw the field of evolution into a dither; according to orthodox evolution theory dinosaurs were extinct long before primates, much less humans, had evolved. But the evidence was being misinterpreted. A closer examination of the footprints by qualified paleontologists demonstrated that what appeared to be human footprints were prints of a dinosaur which left prints which, at first glance appeared human.

Likewise, anti-evolutionists have insisted that a complex structure like an eye could not evolve because it does not work if any part did not do its job. But scientists have shown that a wide range of organisms have eyes ranging in simplicity from mere light sensitive spots to the eyeball with a lens. Each is but a small change from a simpler example, demonstrating that evolution can produce complex structures.

These attempts to discredit evolution are dead-ends that evolutionary biologists have already considered and rejected, not because they don't want to see the theory discredited, but because evidence supports the conclusions. If this is not yet convincing you, let me give you an analogy that might clarify it.

There are some who claim that the Nazi holocaust of Jews and others undesirables never happened. Knowledgable historians do not discuss these claims, citing this as an alternative interpretation of the evidence, nor are these theories taught in history classes. This is because the evidence for the Holocaust is so extensive that it would be irrational to claim it never happened. Historians don't consider the Holocaust a theory which deserves to be viewed as inconclusive because the evidence is so extensive and so clear that no qualifiers need be made. The Holocaust, unfortunately, happened; it is a fact of history, not a theory.

If we consider what could cause people to question the Holocaust, we cannot but conclude that they choose to believe this in spite of the evidence based on bigotry, not evidence. In a like manner, I conclude that those who believe in intelligent design and creationism do so in spite of the massive weight of evidence based on religious beliefs. To suggest that such ideas have a place in science class is as irrational as to assert that anti-Holocaust texts be introduced in history classes. The only reason to even mention these topics in science or history classes would be to demonstrate antithesis of science and history.

2006-11-28T08:51:00.000-05:00

Elephants, Humpbacks, and Humans

In my previous post, I suggested that a number of other species demonstrate many similar traits as humans, suggesting near human intelligence. These traits include the ability to use language, create tools, and interact in complex social hierarchies. Recently, elephants were added to the list of creatures thought to be able to recognize their reflections as an image of themselves, rather than another animal. Self-consciousness suggests an ability to have mental concepts, including an idea of a self. This has also been observed in chimpanzees, bonobos and orangutans, and humans (by two years of age).

Another recent discovery notes similar types of brain cells in humpback whales and humans, of a sort that may relate to intelligence. These types of cells are not found in dolphins, but are found in other primates.

One of the reasons many reject evolution is that they don't want to accept that humans are not special. These people like the idea, promoted by certain religions, that humans were a special creation of God, and that everything in the universe is essentially an elaborate stage. God's attention is focused on us and us alone. This notion has also gone farther, with certain ethnic and cultural groups believing that God does not even favor all humans equally, but gave special information to one tribe of people and no one else. This kind of elitism is betrayed for what it is, pride, when we objectively look at the world. There are many cultures, many religions, and there is beauty and worth in each of these religions, even if none is completely right about everything. Likewise, there are other creatures that differ from us by very little.

It is likely that humans could only achieve our current situation because, in addition to our intelligence, we walked upright, had hands that could make tools, and vocal cords that could make a great variety of sounds. And, as noted in other posts, it is very unlikely that we are the only planet in the universe with intelligent life.

2006-11-28T08:23:00.000-05:00

The following very short article relates to the development of planets around stars, about which I made a post some time ago. I'll quote the whole article, which appeared on globeandmail.com.

Planets really made from dust
Globe and Mail Update
Monday, October 09, 2006

Floating discs of debris do indeed turn into planets, and now the world finally has evidence to prove it.
Scientists analyzing data from the Hubble Space Telescope have at last confirmed the long-held belief put forward by philosopher Emmanuel Kant more than 200 years ago.
Until now, astronomers have detected more than 200 extra-solar planets and have seen many debris disks around young stars, but they have yet to observe a planet and a debris disk around the same star.

Again, this does not relate directly to biological evolution, but it shows that the universe incorporates evolution even in its non-biological history. This is a different meaning of evolution from the evolution referred to in natural selection. This is the more general notion that relates to things which change progressively over time and don't change back.

The idea that planets can form from space dust has been around for a while, as the article notes. Over time, more and more evidence has been produced and this process continues. Now we can safely assert that there are hundreds of billions of hundreds of billions of stars in the universe, and many, if not most, of these have planets around them.

The number I gave above is not just hyperbole of the sort associated with Carl Sagan. The accepted round number for stars in our galaxy is 100 billion. And an all sky survey that counted galaxies reached a similar number of galaxies in the universe. Some of these are smaller than the Milky Way but many are much larger. So a hundred billion hundred billion is accurate, to a few orders of magnitude.

We cannot yet determine if any of these other planets has life of any sort, let alone complex, possibly intelligent, organisms. But if we accept that the universe is a well-ordered place, with the same laws operating here as anywhere else, we can only conclude that there should be a great number of planets with life. Considering the number of animals on earth which have similar intelligence and social lives as humans (apes, dolphins, whales, and elephants), I think it very unlikely that we are the only species in the universe contemplating these same questions.

2006-11-26T21:25:00.000-05:00

A recent search for articles and papers providing evidence for evolution turned up a wide variety of examples.

Evolution of typhoid bacteria
This is fairly technical and I'm not qualified to sumarize it or elaborate on the evidence, but the opening summary reads as follows:

In a study published in the latest issue of Science (24 November, 2006), an international consortium from the Max-Planck Society, Wellcome Trust Institutes in Britain and Vietnam, and the Institut Pasteur in France have elucidated the
evolutionary history of Salmonella Typhi. Typhi is the cause of typhoid fever, a disease that sickens 21 million people and kills 200,000 worldwide every year. The results indicate that asymptomatic carriers played an essential role in the evolution and global transmission of Typhi.

Clearly, these biologists have no difficulty understanding this disease in terms of evolution, and we are fortunate for this, as they are working to keep us one step ahead of diseases that clearly demonstrate a propensity to evolve. This is a growing problem in hospitals, since strains of bacteria are evolving that are not killed by standard antibiotics.

Oysters in bay adapting to illness

This article opens, "Virginia scientists are finding pockets of oysters in the Chesapeake Bay that have adapted to genetically resist the deadly diseases that threaten the broader population. 'We have what appears to be an evolution of disease-resistant oysters,' said Ryan Carnegie, an assistant research scientist at the Virginia Institute of Marine Science." This shows the other side of the "arms race" between bacteria and the organisms they infect. Some have even suggested that this to some extent accounts for continuing evolution rather than a steady-state situation in which all organisms have evolved to some peak level of survival ability.

Wheat's lost gene helps nutrition

Domesticated varieties of wheat have a gene that normally is not turned on. That is, the gene is present, but another gene is needed to turn it on, so that it acts on the development of the plant. By figuring out a way to turn this gene on, scientists have increased the nutritional quality and decreased the time to reach maturity. For those worried about eating genetically modified foods, the scientists have found a way to turn the gene on by cross-breeding domestic and wild strains of wheat. This may help improve the nutrition for people all over the world. These kinds of advances can never be provided by "intelligent design" theory. How would you predict something like this if you had no way to fathom the designs created by this intelligent designer?

New Gene Map Reveals Surprising Differences

This article reports on a new way of comparing gene maps that picks up on subtle differences from individual to individual in something called 'copy number variants' or CNPs. This may be a revolutionary development because it may enable scientists to identify genetic causes of certain diseases. This says to me that the genetic reproduction process is very complex and so there can be lots of variation before something becomes significant enough to cause an evolutionary change.

Evolution can happen quickly, study finds

I'll quote the first few paragraphs, since they say better than I many important points about evolution and how new research is confirming the theory, rather than challenging it.

A new study of lizards in the Bahamas shows that the natural selection pressures that drive evolution can flip-flop faster than previously thought -- even in months.

"Darwin was right about so many things," said Jonathan Losos, a former Washington University biologist who led the study. "In this case he was wrong. He thought that evolution must occur slowly and gradually."

The lizards and their changing leg lengths are yet another case of evolution occurring in real time. From finches that evolve longer beaks in a few years to bacteria that adapt to strange feeding regimens in days, evolution, as a science, has leapt out of musty museums and into the field. Scientists say that, from a political perspective, the cases offer a vivid reminder of the continuous process that some people imagine proceeding only in fossilized fits and starts: first monkey, then man.

The article goes on to describe science at work, testing hypotheses, improving theories. Scientists measured leg length of a lizard on various islands in the Bahamas. Then they introduced a predator and used evolution to predict how the lizards' legs would change in response. They thought the legs would grow longer initially, since the longer legs would allow the normally ground-dwelling lizards better chances to survive by running up trees. Once the population had lived in the trees a while, however, they expected leg length to decrease again, as it provides a better way to get around in the trees. They found the predicted changes.

For another example of how scientists are testing and verifying evolution, see the next article.

Robot Tadpole Sex Sheds Light on Vertebrate Evolution

Quoting the first few paragraphs:

The distant forebears of humans and other vertebrates were much squashier than their descendants. They possessed flexible rods known as notochords that served as primitive backbones, but no vertebrae. Scientists think vertebrae evolved to
help our ancient predecessors swim more powerfully by stiffening the body so attached muscles could generate more force.
"The fossil record shows vertebrae evolved independently at least four separate times. That shows they must really be functionally important," said vertebrate physiologist John Long at Vassar College in Poughkeepsie, N.Y.

To test this idea, Long and his colleagues built robot fish with backbones of varying strength to simulate extinct animals. They then "mated" the best swimmers to see how generations of "offspring" evolved to swim better.

Here again, a test of the idea of evolution, with no guarantee that the results would confirm the hypothesis. This is a physical version of something that is often done on computers, creating "genetic algorithms." It demonstrated that the hypothesis was confirmed. The faster swimmers, when "mated," (that is when "computer simulations that modeled the genetic mixing that occurs during sex to produce the next generation" were used to generate new designs for the swimmers), produced a structure that does stiffen the region down the center where the spinal cord would be in primative organisms.

But they also found that the hypothesized evolution only accounted for 40% of the improved swimming speed. Evolution found other ways which the scientists had not thought of to improve the "design" of the model. They plan to introduce a robot predator to test how well visual sensing device similar to something in fish can improve through evolution.

2006-11-06T21:44:00.000-05:00

Evolution of Complex Organs

One of the most common attacks on evolution is to assert that complex organs such as the eye could not evolve since they only work when all parts are present. National Geographic, obviously intent on showing that this claim is false, has published an article in the November 2006 issue detailing the wealth of evidence for how such organs evolve. For the Internet version of the article, see http://www7.nationalgeographic.com/ngm/0611/feature4/.

The jist of the article is that marvels such as the eye, the arm, feathers, and flowers are, in fact, built up from primative beginnings through minute changes that over millions of years add up to the organ in question. Furthermore, the same genes are used in different organisms to develop different forms of an organ or limb. For example, "Insects and humans use the same genes to tell cells in their embryos to turn into photoreceptors. And both kinds of photorecptors snag light with molecules known as opsins" [p. 126]. This is as would be expected if eyes of insects and humans evolved from some very early common ancestor which evolved a simple way to detect light. Later elements like the lens of a more advanced eye evolved out of a transparent protein called crystallins, which existed well before the eye used them to build a lense.

This puts the lie to another accusation made against evolution, that only microevolution has been demonstrated (slight changes within a given species, such as foxes with different colored fur in the arctic and the temperate zones), not macroevolution (the evolution of new species). Small changes, over a long enough time, can lead to major differences in the way a set of genes shapes the organism. It is not a quirk of some intelligent designer that all mammals have virtually the exact same skeleton, even though the bones are often put to very different uses: whale "hands" are fin for swimming, bat "hands" form wings, and human hands can create complex tools. The same goes for feathers, which evolved from scales, serving various uses during the intermediate period between scales and flight feathers.

Despite all this evidence, the same false accusations are made over and over and over again by proponants of creationism and intelligent design. Yet they claim it is the scientists who are dishonest, giving the public a false sense of certainty regarding evolution. [For one example, see: http://www.discovery.org/scripts/viewDB/filesDB-download.php?id=118 .]

2006-11-04T21:58:00.000-05:00

Evolution of the Human Brain

http://www.physorg.com/news81709891.html

The above link is to an article describing a discovery relating to how the human brain differs from the brains of other mammals and may shed light on how our brains have evolved to allow more complex thought. To quote the article: "Cell adhesion controls many aspects of brain development including growth and structure, and enables neurons to connect with other neurons and supportive proteins. Differences in the molecular connections of human neurons compared to the neurons of chimps, mice and other animals, could help explain why the human brain is capable of far more complex cognitive functions."

This discovery is related to DNA sequences that determine when genes are switched on or off. The effect of DNA is not just to determine the genes and hence the morphology of the organism. The same genes can generate different features in an organism depending on when it is allowed to work and when it is prevented from working. This could explain why humans and chimpanzees share 98 percent of the same genome, yet the end result is quite different. This provides a new avenue for evolution, one that does not change the genes but when they turn on and off. For more on this idea, see the next article.

2006-10-10T08:07:00.000-04:00

Talking Bones

The September 2006 issue of Discover magazine had an article about a scientist who practices a science called paleopathology. This is the application of the science of pathology, which attempts to understand health problems of living things, to paleontology, which is the study of fossils. Since fossils are mostly of the bones of creatures who lived so long ago their solid remains have turned into stone, studying the bones in light of our current medical understanding can reveal many things about the creatures of the past.

In the article, the scientist, Bruce Rothschild, discusses his findings about a variety of ancient and not so ancient creatures. He has challenged the idea that certain dinosaurs walked upright, because their bones do not demonstrate the types of fractures and other deformation that normally come from such a posture. He has also bolstered the theory that dinosaurs like the Tyrannosaurus rex did walk upright. Other findings suggest that T-rexes may have ad rough sex.

Another finding relates to creatures that dive deep underwater to catch prey. Diving too deep for too long and rising too quickly can lead to a condition called the bends, in which bubbles of gas form in the bloodstream which can cause damage to the brain and joints. But Rothschild has found evidence of the bends in the bones of certain diving creatures of the past. This suggests that some creatures evolved a way to cope with this condition and survive where others would be killed or crippled. He hopes this may lead to ways of allowing humans who dive deep to cope with the same problem.

Critics of biological evolution try to cast doubt upon the value of fossils in proving evolution. In fact, fossils are a very rich window on the past, allowing us to understand many intricate details of life forms that are no longer around. The changes in bone structure over time gives enough evidence of evolution to establish the theory, even if there were no other evidence for the theory (which there is). This shows the lie that we cannot test the theory of evolution because we cannot test theories with experiments.

Just as the forensic scientists who investigate crimes can testify to events of the past based on evidence found in the present, so can paleontologists describe the creatures of the past based on the evidence they have left for us to find millions and even billions of years later.

2006-10-10T07:33:00.000-04:00

Evolution of Planets

I have not posted in a while, not because there is no news relevant to evolution, but because I have been in the middle of a career switch and rather busy.

Recent news reports have announced new and significant evidence for the hypothesis that planets form from dust that is scattered in space and gradually coalesces due to the mutual pull of gravity. The idea has been around a long time and I know of no reputable scientists who questions the idea. It is in perfect accord with both theory and observation. But science likes to confirm with more than plausibility. It likes to see evidence that definitively establishes a theory beyond any doubt.

For some time now, powerful new telescopes such as the Hubble Space Telescope have been detecting planets around stars. Telescopes have also detected stars with a disk of dust around them, something like our planet Saturn with its rings. The latest observations are of a planet and a disk around the same star and the planet is aligned with the disk.

What does this have to do with evolution? Evolution requires time. There is a wide range of evidence to suggest that our planet has been supporting life for several billion years, with the planet forming about 4.5 billion years ago, perhaps a billion years after the formation of the sun. This idea is also consistent with observations of other star systems, but now we have an observation that fills a small gap in this evidence.

It is also evidence that evolution, in a general sense, is a universal aspect of our universe. Science asserts that all stars form from clouds of dust and simple atoms and molecules that can be observed throughout our galaxy and others. When a critical amount of this matter forms, the forces of gravity overcome the forces holding the atoms apart and we begin to get nuclei fusing together and giving off energy, which accounts for starlight. It also keeps the star from collapsing further, as the energy given off pushes atoms apart on average as much as gravity pulls them together.

The earliest stars were probably made of just two elements, hydrogen and helium, the simplest of atoms. But when stars are really big, they burn through their nuclear potential and collapse some more and this leads to an explosions called a nova or a supernova. This fuses heavier atoms to form the heaviest of atoms so far observed. All this matter drifts out from the star, but globs of it can be drawn together again by gravity and a new system can form. Some of this heavy matter can form planets.

Some planets, such as earth, have the right amount of water and other chemicals to foster life. That life necessarily starts out simply, as complex self-replicating molecules. Over time, the process of natural selection begins to nurture evolution of these forms, and the process can lead to creatures such as ourselves.

So simple atoms evolve into heavier atoms which evolve into chemicals which evolve into life which evolve into self-conscious life, which evolve things like the Internet and blogs. Creationists and intelligent design exponents do not say much about the evolution of stars and planets. First it contradicts the idea that the universe is much older than indicated in Genesis. It also makes the idea of biological evolution all the more plausible.

Evolution happens. It is a wondrous thing. It is only a problem to those whose religion clings to the idea that human beings are extra-super-duper-special, the center of universe. But we don't have to be the center of the universe to be special or wondrous.

2006-06-17T22:43:00.000-04:00

Secrets of Bat Machismo From Discover magazine, May 2006, p. 17: A species of bat has been discovered with very large testicles and very small brains. This is explained as follows: "Testicles are almost always bigger in animals species in which females mate with multiple partners.... When females are promiscuous, the sperm of different males must compete to fertilize each egg. Because males with more sperm have a better chance of producing offspring, the frequency of large testicles in those species increases. The pattern holds among all animals, including primates. Gorillas, who keep their harem close, have small testicles, while libertine chimpanzees have large ones. Those of humans, whose mating habits fall in between, are midsize."

The connection to brain size is that both a large brain and large testicles take a lot of metabolic resources. So we would expect that bats that need big testicles to gain an advantage in reproducing would have smaller brains to compensate.

Evidence was collected for 334 bat species. "In species with unfaithful females, males invest almost five times as much in testicles and 27 percent less in brains."

2006-06-17T22:36:00.000-04:00

Origin of the Ear From Discover magazine, May 2006, p. 16: "Our earliest ancestors may have breathed through their ears." "The tubes that form the middle-ear canal in humans probably evolved from a pairof gill-like holes that allowed primeval sea creatures to breathe from the back of their heads."

The evidence: fossils dated at 370 million years ago of an intermediate species between fish and the first four-limbed animals to crawl onto land. This species "had small bones in its skull that appear to be early analogues of both ear canals and the gill system in some modern fish." When the creatures evolved to walk on land and breath air through the mouth, the canals were no longer needed for breathing, could develop into ears.

2006-06-17T22:24:00.000-04:00

From Discover Magazine, May 2006, p. 13: Are We All Asians?

While most biologists agree that humans have evolved from earlier species of primates, this article points out that the location of these early ancestors of humans is not established. Some believe the evolution occurred in Africa and that humans spread elsewhere relatively late (80,000 years ago). Two scientists, Robin Dennell and Wil Roebroeks, suggest that we don't have enough evidence from Asia to discount it as a starting point for human evolution.

Another scientist, Spencer Wells, supports the Africa hypothesis, but added, "That Homo erectus could have origins in Asia would be potentially shocking, but I think that what Roebroeks and Dennell are saying reflects the state of the field. We certainly don't have enough fossils. Perhaps we are never going to be able to test the hypothesis."

This shows how open scientists are to having their favored interpretation of the evidence overturned by new evidence. It is how science advances.

Note that if new evidence turns up for humans evolving in Asia, it would not discredit the idea of evolution, only a prominant hypothesis about a particular detail of it.

2006-06-17T21:52:00.000-04:00

Introduction: Evolution Defined

One popular misconception perpetrated by intelligent design proponants and creationists is that evolution is "just a theory," implying a significant degree of uncertainty. There are two aspects to correcting this misconception.

First, evolution is not in any sense a theory, speaking strictly of the concept of evolution. Evolution refers to a type of change that has nothing theoretical about it, any more than the concept of velocity is a theory. Velocity refers to an observable phenomena associated with motion. Evolution refers to a method by which certain changes can come about in a certain type of population. One can point to many examples of it, and one can create any number of examples in computer simulations. Evolution happens.

Evolution happens under the following circumstances:

1) One has a population of entities which are nearly, but not completely, identical.
2) These entities reproduce or are reproduced such that the copies are nearly, but not completely, identical to the original. Earlier members of the reproducing population are eventually replaced by these copies.
3) There is something about the situation which causes certain individuals of the population to produce more copies of themselves than other members. This happens consistently over a number of generations.
4) The differences in reproductive rates eventually brings about a change to the general characteristics of the population compared to an earlier generation.

Examples: One could write a program which starts with a set of 1000 numbers, each number between 1 and 100. The program picks a number from the set at random and evaluates whether or not the number is prime or not. If the number is prime, the program copies the number twice into a new number storage area. If the number is not prime, it is reproduced just once in the new area. Once the new area has 1000 numbers, the program starts again with the new set of numbers. Each iteration of the program will generate a new set of 1000 numbers. If this is kept up long enough, one would find almost all the numbers in the latest set to be prime numbers, even if the original set had only a nominal number of primes.

Other examples include selective breeding of dog or horses to produce animals with a certain trait, competition in the marketplace which over time changes the features on a product such as telephones. Even ideas evolve. Ideas exist in people's heads or minds, and are reproduced as new people are born and are exposed to the ideas. Ideas like racism were once very common, but today, the idea is found less and less.

This is not controversial. But when most people hear the word evolution, they think of the evolution of the species. This refers to the theory that the differences in animal and plant species that we observe in the world today are the result of a process of evolution. In this case, the population of entities is a biological creature such as a redwood tree or a robin or a dolphin. These populations reproduce by way of copulation and giving birth to new members, who grow up to replace the parents. Most dolphins are very similar to each other, but not identical. The selection occurs when the environment changes so that creatures with some feature have a better than average chance of surviving and reproducing than other members. For example, members of the species with a particular coloration might prove harder to see in the new environment, meaning they get captured by predators less frequently and so reproduce more frequently. The gene that produces the coloration is more common in the next generation, so more of the offspring have the coloration. The process can lead to the entire population changing from one color to another.

The mechanism of evolution is perfectly logical. The only thing theoretical was (back when the theory was first proposed) whether or not the differences in creatures actually observed could be explained by environmental selection. Over time, more and more evidence has been found to support the theory of evolution of species until now, evolution is considered the actual explanation for diversity of species. The only things in questions are particulars of how quickly changes can occur and the mechanical details.

This blog will be listing examples, hoping to demonstrate the reasonableness and value of this idea.

POSTING GUIDELINES: Please limit comments to the relevance of the particular example as evidence for natural selection as the explanation for the diversity of species. This is not the place to debate religious doctrine. (I'll have another blog where that will be appropriate.) Comments which are abusive will be deleted. Off-topic comments will be deleted.