Monthly Archives: February 2007

Got milk (alleles)?

As you probably know, everyone should drink milk. Lots and lots and lots of milk. All your life. Or so says the American Dairy Industry, often using those sexy posters of famous people with milk smeared on their faces.

The truly amazing thing about those posters is that the people in them more often than not seem to have an ethnic identity that I, as a trained Biological Anthropologist (and thus keeper of this sort of knowledge) can easily see contraindicates milk consumption. Most of these individuals would likely be unable to break down the lactose in the milk because they have the “wild type” or “normal” allele that facilitates the shutdown of lactase production some time in early life.

Now let’s be clear about this. We humans are mammals, and as mammals, we drink mother’s milk while young. This is facilitated by the production of lactase, an enzyme that breaks down the main energy bearing molecule in milk, the sugar lactose. But your basic well adapted mammals should not bother producing the enzyme lactase after weaning normally occurs … maybe a few years after in a long-lived mammal like humans … because it is inefficient and potentially risky to produce enzymes you don’t need.

Why is it inefficient? Well, there are thousands and thousands of enzymes and if we just produced all of them all the time in all our cells, that would be really costly of raw materials and energy, both of which are required to produce them. So, evolution has shaped, via the brilliant designer of Natural Selection, our multicellular bodies to produce enzymes only in the cells they are needed in (from which they may be exuded on occasion, as is the case with lactase, a digestive enzyme). This is much more efficient. By extension, the system should be (and usually is) selected to produce specific enzymes when they are needed instead of all the time from birth to death. By doing this we save a lot of raw materials and energy.

Continue reading Got milk (alleles)?

Global Warming, the Blog Epic ~ 01 ~ Introduction

The IPCC report is out, “An Inconvenient Truth” has been honored by the academy, a sea change is happening in the way that climate change news is being reported, and you can bet the Right Wing and the Ree-pubs are as we speak working up new Talking Points and Spins to deflate the urgency of the issue. It is an axiom that in reporting science, there are two (not one, not three or four, just two) sides to every issue, and one side is the plank nailed to the Democratic Party Platform, and the other side is the plank nailed to the Ree-pub Party Platform. This is a truth as stable and reliable as the fact that Home Depot will always sell 2” X 4” studs and plywood in 4′ X 8′ foot pieces. We are already seeing the dubious dichotomies forming up. For instance, yes, the Antarctic Ice Sheet is sloughing off the continent, but it is opening new and wonderful opportunities for both shrimp and scientists. Yes, global warming is real and is anthropogenic, but the Average American thinks, according to Polls, that it is only the third or fourth most important issue. And so on.

The global warming debate has been running continuously since the now very obscure publication of Moment in the Sun: 1968” by Dr. Robert Rienow and Leorna Train Rienow. Most people think of the literary beginning of the environmental movement has having been “Silent Spring” by Rachel Carson, and maybe so, but for me, it was Rienow. This is partly because “Moment…” was the first book I read on the topic, one of the first “adult” books I read at all, and on those early mornings before school I was able to watch Dr. Rienow on that crazy new fangled box … the black and white TV my parents had just acquired … on a thing called “Sunrise Semester” produced by SUNY-Albany. Rienow would lecture, and he and his wife and (I assume) the occasional student would put on skits lampooning industrialists and other polluters.

I remember one day, years after having last seen Sunrise Semester, having just acquired a car and a license (at a ripe old age of 18 or so) exploring the territory south of town, along the Hudson River. I encountered an old narrow road running down into the wooded valley from a minor highway, and took the turn thinking it would lead somewhere interesting. Soon enough there was another turn onto a narrow gravel way called “Holly Hock Hollow” … that name sounded familiar, but I could not place it. So I made that turn as well. A mile and a half or so later, the road leveled off to join the floodplain of a small creek, and I started to see little wooden signs in the forest, extolling in a few words here and there the virtues of nature, and imploring the reader to “leave no trace of your visit” and “respect the trees and animals” and such. Eventually I spied, along side the road where a stone wall opened to a gate, a sign: “Holly Hock Hollow Farm ~ Robert and Leorna Rienow.”
Continue reading Global Warming, the Blog Epic ~ 01 ~ Introduction

Racism, Creationism, Darwinism

Racism and it’s various manifestations such as eugenics is a Janus Faced monster of human society. One side speaks to people’s fear and hate, and is social and political. It speaks a sermon to the angry and downtrodden who love to hear that their “race” is superior, or to the social managers and engineers who benefit from a handy excuse to explain the results of repression and economic inequality as the natural outcome of history and circumstance beyond our control and thus not the fault of those self same social managers and engineers.

The other face is the biological one, the scientific description of “race” itself, and the scientific explanation for racial differences.

Each of these aspects of modern racism can act independently and to some extent have different histories, but by and large they are two parts of the same trend. Prior to Eugenics, the biological side of this monster was not scientific, and was in fact typically religious. When European Christians needed to explain the people of the New World (how the heck did they get there, and who were they, really?) or the “savages” of Africa, they turned to the bible … and there found the basis for Continue reading Racism, Creationism, Darwinism

Home Schooling Creationist Science Fair 2007

Well, Amanda, Julia and I stopped by the 2007 Home Schooling Creationist Science Fair over at the unique Har Mar Mall in Roseville, Minnesota. Very few of the shoppers passing through the mall seemed to take much of an interest. There were a couple of moms showing each exhibit to their children, reading off the relevant parts … “Evolutionists think fossils take millions of years to form, but creationists have shown that this is not true…” and so on.

Science Lesson Plans

Science is probably one of the hardest subjects to teach. Many students just don’t see the connection between abstract science in textbooks and how it works and affects them in real life. That’s where a variety of science lesson plans can help teach science to your students more effectively.

The Social Studies Help Center

Help for 11th graders. There are class notes, numerous Supreme Court case summaries and information on how to write a research paper.

The 15 or so exhibits demonstrated a wide range of levels, from what must have been pre-school to at least one clearly done by the parents (that one, present yesterday during an earlier trip to the mall, but missing today) compared the affective behavior of childcare-kids vs. home school kids.) Most of the exhibits had a quote from “the scriptures” related in some way to the exhibit. For instance, my favorite: a very young child’s exhibit (I’m guessing) on bunnies. The Scripture: “God has arranged the parts in the body, every one of them, just as he wanted them to be” (I Corinthians 2:1912:18). Of course, I Corinthians 12 is about the unity of the spirit and the body, and that bit about the arrangements of the body parts is part of a sort of mini parable in which each part of the body stupidly asks “If I am not an eye, I am not part of the body?” and so on. So note, fellow rationalists. As annoying as it is when creationists “Quote Mine” from the scientific literature, take heart. They don’t get in much trouble for doing that, but when the quote mine from The Bible, well, I assume they are going to Hell for that. What goes around comes around.

Anyway, the “Bunny” science fair entry was my favorite not because of the misquotation of scripture, but because of the hypothesis being tests:

Question: What do bunnies do?

Hypothesis: God made bunnies with many parts that work together so they can do lots of things.

We all had to laugh when, on the way home, Amanda slammed on the breaks to avoid flattening a bunny tearing across the street. “Well, praise the lord, all the parts seem to be working…”

Many, really the majority, of the exhibits were just regular (mostly half baked) science fair exhibits that had some scripture slapped onto them. In other words, despite the occasional exhibit clearly motived by pure creationist philosophy, most of the kids ended up doing some kind of science or another. Funny, I don’t remember ANY of the 200 exhibits or so at the Brimhall Fair (see this on Julia’s entry) held earlier in the year just down the street at a Real School addressing creationist ideas. But when the kids enter into a creationist fair, they can’t seem to help themselves from doing some actual science.

Nonetheless, the overall quality was unimpressive, as one would expect from the home school environment.

After my first visit to the fair, I swooped into Barnes and Noble and bought myself a copy of Dawkins “The God Delusion.” … I just needed to do something. After this trip, I think I’ll just take a shower.

Flock of Dodos Rocks

The new feature-length documentary by filmmaker and evolutionary biologist Randy Olson, “Flock of Dodos” was shown at the Bell Museum last night. Executive Producer Steven Miller, and the Minnesota Evolutionary Musketeers, Scott Lanyon, Mark Borrello and PZ Myers were in attendance to lead a discussion afterwards, moderated by the Phil Donahue Like Shanai Matteson.

Randy Olson left the world of science to pursue a career in Hollywood, and after about 10 years of not paying a lot of attention to his former career, learned that a new theory had emerged to explain the diversity of life: Intelligent Design. This film chronicles his quest to find out what Intelligent Design had to offer, and to explore the political and social conflict associated with the rise of this new idea.

It is an absolutely fair film in that both “sides” are given ample opportunity to demonstrate merit. As such, of course, the Intelligent Design side of the discussion appears significantly weaker and sometimes downright foolish, and occasionally nefarious.

This film has been well received. Many reviewers note a comparison with Michael Moore … I have to say, I’m a Michael Moore fan (not a nut over him, I just think he has talent and a sufficiently demented sense of humor to enjoy). Olson is NOT a Moore clone, despite the similarities. While Olson’s voice is clear in Flock, it is not “in your face” but rather a voice that is always there drawing out, sometimes cajoling, others to be heard.

Olson’s experience as an evolutionary biologist turned filmmaker placed him in a unique position. The evolutionary biologists he interviews are either people he knows or people who know people he knows .. in other words, members of his extended professional community. This allows him license to poke fun at them. It also allows him to treat their position in the film with a respectful rather than snide humor.

On the other side of it, it turns out that Olson is a native Kansan, and his mom (spiritualist “Muffy Moose”), one of the stars of the film, lives around the corner from one of the principle players in the Kansas ID movement. Olson’s family and community ties, and his being a Prairie Homeboy himself, gives him the ability to treat the ID representatives with simultaneous respect and humor.

While the Intelligent Design “movement/theory” (both in quotes, you will note) is trumped by the science in this film, the weakness of the scientists as a group … especially when it comes to making their case to the public … is clearly underscored. Olson replicates the famous “Harvard Poker Game” (which used to be played at my good friend Irv’s house back in the day) at which several scientists sit around talking about Intelligent Design. Each time one of the scientists comes up with a multisyllabic erudite utterance (a fancy word), the film stops and goes to a black screen on which a definition of the word is typed out. In this and other ways, the scientists are duly mocked.

But I must say the opportunities Olson was able to exploit for mocking the Intelligent Design proponents were myriad and wonderful.

So while the IDers in general were trumped, the BIG loser, losing poignantly, painfully, even Michael-Mooresquely, was ID Central itself, the Discovery Institute. They are shown to be deeply, darkly, impressively evil. I won’t give you the details …. and it is nothing like the main point of the film … just go see it. It is worth noting that while the Discovery Institute would not give Olson the time of day at the time he made the movie, they have since reacted strongly and very negatively to it (creating an entire web site about it “Hoax of Dodos”). I would give you the link to it but, well, they can go screw themselves.

The post viewing discussion was as expected: Informative and lively. Unlike the recent situation in Seattle, the filming was not infiltrated by the Discovery Institute, as far as I know. Excellent questions were asked, and points were made. The two creationists who spoke out were low key and were treated respectfully.

The film is currently available from DER, at institutional-use price and license. If you are with an institution, go buy it now on the company’s dime!!! It will be on Showtime a bit later, and around summer, available from all the usual sources as a home-use DVD.

I’d like to express a particular thanks for Steve Miller for coming to the Twin Cities in sub-zero weather to view the film with us (but I hastily add, I think Steve is a Minneapolitian, but since he currently lives in the Deep South, this could not have been easy).

Cafe Scientifique: Myers Causes Woman to Become Closer to Jesus

Amanda and I just returned from the Bell Museum sponsored by Cafe Scientifique at the Varsity Theater in Dinkytown, Minneapolis, and it was a very interesting evening.

Panelists Scott Lanyon, director of the Bell Museum and ornithologist, Mark Borrello, Historian of Science, and PZ Myers, Fire Breathing EvoDevo Biologist, each gave 5 minute summaries (none of which lasted more than 10 or 11 minutes) of various aspects of the current social debate over evolution, then fielded questions from an audience that seemed much of the time all too compliant. Many thoughts came to my mind during the discussion (which I stayed tactfully away from) the first of which is that these three guys did a great job at driving home a variety of points. I won’t summarize their perspectives, but rather, I’d like to give a few gut reactions.

I think starting right now we have to substitute the term “Evolutionary Biology” for the often used “Evolutionary Theory” instead of constantly whining about how “people” misunderstand the use of the word “Theory.” It is the Theory of Relativity, but the physicists say just “Relativity.” The Periodic Table of the Elements is a theory, but the word “theory” is never used there either. We are just asking for trouble and should not be so surprised when we get trouble.

It was interesting to see the range of perspectives, running from left to right (on how the panelists were arranged on the couch) but from centrist to left with Lanyon advocating a truce between religion and science on one end and Myers saying of religion “It’s wrong all the way down” (a subtle reference, no doubt, to turtles).

The speakers represented a fairly typical range of biological fields and thinking, even in the way that the behavioral aspects of biology were not especially considered. For instance, Borrello extolled the virtues of The Origin together with The Selfish Gene as representing a kind of range of explanatory power in biology. This is OK, and not wrong, but biologists who study mainly genes or inverts or cells often forget that starting with Hamilton in 1964, and running through a pantheon of other fieldworkers, theorists, and experimental biologists, there is a lot of strong theory that relates almost entirely to organisms with brains (the field of behavioral biology). This missing area was also felt (by me anyway) when Borrello (or Lanyon, can’t remember) noted that there have been three major revolutions in biological science: Darwin (Natural Selection), Mendel (genetics) and EvoDevo. Clearly, Behavioral Biology and Behavioral Theory is one of the revolutions (a.k.a. sociobiology). Nonetheless, the speakers did a fine job fielding the one behavioral question they got, on homosexuality.

The point was made that we live in a science and technology based society, yet Americans disrespect science to a large degree. This is an interesting point. We are actually a Christian Nation, according to some, and this conflict is at the heart of the discord.

I was left with the very strong feeling that science is in need of strong cultural leadership. Instead of our society requiring that office seekers be good christians, we need credible politicians … and movie stars and recording artists and other cultural icons … sticking their noses up at creationism and promoting the premise that of course, we do live in a science and technology based society so we should give more respect to the scientists and the theoretical and empirical knowledge they work with.

This was a real Minnesota Experience for me, coming from “out east.” At one point an anti-religion/pro-atheistic remark was made (by an audience member) and it drew applause. That, I get. And had this event happened in Cambridge Mass, that would have happened. But then, just at the end, what was supposed to be the “last question” turned into a rant against PZ Myers by someone who claimed to be “non religious” and who’s hero was none other than Darwin Himself, but who believed that anti-religious sentiment underlying at least part of the above mentioned spectrum was even more arrogant than Myers had claimed creationists to be. THAT also received applause. THAT would not have happened in Cambridge.

The moderators, feeling that this was a bad “last question” handed the mike to another person. Big mistake. She took the discussion down several notches, explaining (to her credit) that she as a christian still supported science and believed in evolution, but then she did not stop talking, and went on for a while about how she loved Jesus and how this discussion did nothing more than to make her closer to Jesus and so on and so on. More applause.

I don’t think anyone was converted, but thirsts were slaked. The audience wanted more, and more, I think, they shall have at upcoming Cafe Scientifques here and elsewhere. I ended the evening with a discussion with Gordon Murdock that included the idea of doing a Cafe Scientifique sort of format for High School and Grade school kids (same format, minus the beer). And I hope all three of these panelists will be available for that.

The Big Bang and Stuff

Dialog from Annie Hall:

Doc: Why are you depressed, Alvy?
Mother: Tell the doctor … It’s something he read.
Doc: Something you read, heh?
Alvy: The universe is expanding.
Doc: The universe is expanding?
Alvy: Well, the universe is everything, and if it’s expanding, someday it will break apart and that would be the end of everything!
Mother(shouting): What is that your business? (to doctor) He stopped doing his homework.
Alvy: What’s the point?
Mother: What has the universe got to do with it? You’re here in Brooklyn! Brooklyn is not expanding!
Continue reading The Big Bang and Stuff

PKU: An exploration of a metabolic disease

Phenylketonuria (fee-null-keet-o-noo-ria), mercifully also known as “PKU” (pee – kay – you) is a disorder in which phenylalanine, an essential amino acid, is not broken down as it normally would be by an enzyme (phenylalanine hydroxylase) and thus accumulates (in the form of phenylpyruvic acid) in the body. Normally, Phenylalanine hydroxylase coverts phenylalanine into tyrosine, another amino acid, which has a number of different functions.

This is bad because buildup of phenylpyruvic acid has several negative effects, the most important being to interfere with normal development of neural tissues. Continue reading PKU: An exploration of a metabolic disease

Charles Darwin Bicentennial – Iguanas, a “most disgusting, clumsy lizard…

…They are as black as the porous rocks over which they crawl & seek their prey as from the Sea. — Somebody calls them “imps of darkness”. — They assuredly well become the land they inhabit. — When on shore I proceeded to botanize & obtained 10 different flowers; but such insignificant, ugly little flowers, as would better become an Arctic, than a Tropical country. — The birds are Strangers to Man & think us him as innocent as their countrymen the huge Tortoises. Little birds within 3 & four feet, quietly hopped about the Bushes & were not frightened by stones being thrown at them.” [Darwin’s Beagle Diary (1831-1836)].

And thus we get a hint of Darwin’s impressions of the Galapagos, and in particular, that Island’s marine iguanas.

The Iguana family is Iguanidae, but most Iguana’s you’ve cuddled in the pet store are members of the genus Iguana (and most likely species Iguana iguana.) The Galapagos Islands have two or three species of iguana: The Land Iguana is Conolophus subcristatus and Conolophus pallidus, or perhaps is actually the subspecies Conolophus subcristatus pallidus. The marine iguana is Amblyrhynchus cristatus.

The two genera of iguana on the Galapagos seem able to interbreed, though they otherwise also seem to make good, distinctive species. (No, it is not really true that inability to inbreed is “THE biological definition of species….” it is more complex than that. A topic for another time, perhaps.) The phylogenetic relationship among the Galapagos iguanas and continental iguanas is similar to that among the finches and other Galapagos animals… complex and more complex because of the apparent fact that while the oldest of the Galapagos islands is about four million years old, earlier islands, perhaps going back twice that age, formerly existed but are now eroded down below sea level. One wonders what will happen next ice age (or what happened last ice age) when a 120 -150 meter drop in sea level exposes some of these islands! The point is that these volcanic islands have a complex history, and it is likely that the islands themselves have a complex relationship to the distant continent. Again, the topic of another post perhaps.

The following passages from Darwin (1839) Continue reading Charles Darwin Bicentennial – Iguanas, a “most disgusting, clumsy lizard…

Charles Darwin Bicentennial – Notebooks

Darwin published hundreds of pages of text, but he also kept notebooks many of which come down to us today. They can be roughly divided into two aspects, the Beagle field notebooks of 1831 – 1836, and his later notes. Sometimes these notes are found in a single book, and one way they are told apart (when otherwise undated) is by the orientation of the notes themselves. Darwin wrote “portrait” style in the field, but “landscape” style in the lab.

Many of the notebooks are preserved at Down House, Darwin’s residence. Down House has 14 Beagle notebooks, one crossover, and one post-voyage notebook, as well as a fragmentary notebook which is believed to contain post-voyage notes.

The complete transcription of all but one of the Down House Notebooks is available on The Complete Works of Charles Darwin Online. The exceptions are previously published books, for which the publication is available at the same web site.

It is in these notebooks (as well as letters) that one can get a glimpse of Darwin’s thinking about evolution and the evolution of his thinking. Continue reading Charles Darwin Bicentennial – Notebooks

Charles Darwin Bicentennial – Gauchos

Painting of a Gaucho
Click to visit Obkouna Art Works

You may have noticed that these posts on Darwin are (so far) in alphabetical order. So this means, if I’m doing Gauchos, I must not be doing Fuegians. Maybe I’m saving Fuegians for 2009!?

But I will mention them. The Fuegians live in Tierra del Fuego (no surprise there) way down at the southern tip of South America. Most people know that, but did you also know that when the Beagle departed Portsmouth Harbor in 1831, it was carrying three Fuegians previously captured by Fitzroy and brought to England?

The Gauchos are the cowboys of the so-called Southern Cone and Pampas. The Gauchos are a Latin American version the horse mounted pastoralists that emerged wherever four things are found together: Grasslands, horses, people and cattle. Like all horse-mounted pastoralists, they have been known to have certain cultural tendencies or traits. These include being incredibly good horse riders. It includes a disdain for any sort of locomotion that does not involve a horse. The Gauchos are held in high esteem as a symbol of trustworthiness and strength, this symbol commonly exploited in regional politics in Argentina and Brazil, or by sports teams (in a mascot-like fashion), even in North America.

The Gauchos are beings with four hooved-legs and two heads because a Gaucho is nothing without his horse. Most wars in the region required Gaucho calvary.

Darwin spent a fair amount of time among the Gauchos, and both Darwin and Fitzroy Continue reading Charles Darwin Bicentennial – Gauchos

Charles Darwin Bicentennial – Finches

Darwin’s finches are a classic and historically important example of a species radiation (sometimes called an “adaptive” radiation, but that implies a specific assertion about the cause of the radiation which may not be appropriate in all cases). During the five weeks that Darwin spent on the Galapagos in September, 1835, he made a number of observations of these birds, but they did not occupy his time or attention more than any other aspect of this remarkable archipelago of islands. It seems that Darwin did not recognize all of the finches as finches, thinking some were of an entirely different group of birds, and in some cases, the variety seen across some of 13 or so species was initially interpreted by Darwin to represent a notably large range of variation in a single species. Please remember, Darwin was a rock man more than he was a bird man, at the time.

John Gould was a bird man, the most famous of his time at least in England, and he is the one who re-identified specimens mistaken by Darwin to be three or four different kinds (blackbirds, grosbeaks, and finches) as representing about a dozen different finches that had diversified into distinctly different forms.

There is even a Vampire Finch. And, even more amazingly, there is a Vampire Finch Movie!(click here to find out more…)

There are two separate dimensions to variation in these finches. The overarching pattern is that different species are found on different islands, owing to a combination of genetic drift and local adaptation, the other is that different finches living in overlapping geographical ranges had different adaptations for differing diets. One gets the impression that Darwin was struck more by this first aspect of variation than the second. This pattern of variation … island by island … also applied to other animals such as the tortoises.

The phrase “Darwin’s Finches” was first advanced, or at least popularized, by David Lack, the famous ornithologist who also advanced a version of group selection theory, in the 1940s.

Here is a list of the species cribbed from Wikipedia: Continue reading Charles Darwin Bicentennial – Finches

Charles Darwin Bicentennial – Coral Reefs

As Europeans plied the seas in search (and ultimately management) of colonies and conquests, they learned the practical geology they needed to find their way and avoid wrecks. Everyone knows that Charles Darwin’s opportunity to spend several years on the Beagle ultimately rested on the British Admiralty’s need to improve navigation maps, especially along the South American coasts. The near shore conditions change, some of the existing maps were not adequate, and the size of ships was increasing so once-safe passages no longer necessarily were. The Beagle’s Captain Fitzroy had a reputation was for tenacious accuracy in map making and navigation, and the fact that a one or two year voyage (as planned) more than doubled in its time is a testament to this.

One of the features critical to navigation is the coral reef. Reefs provided an excellent way to wreck your ship in a storm as well as one of the best ways to Continue reading Charles Darwin Bicentennial – Coral Reefs

Charles Darwin Bicentennial- Beagle and The Voyage

The point of the voyage of the Beagle was to make an accurate survey of the coastal areas of South America, and to run a chain of chronometric readings around the world. The making of geological maps of all of the regions visited was also on the “to do” list for this expedition. Darwin was well matched for this job, because his main interest and to a large degree his primary training was geology. All this stuff about Evolution and Natural Selection was to come later. Darwin knew he would be making extensive collections of biological materials and prepared for this by seeking advice from his mentors on the methods of preservation and shipping of preserved plants and animals, and he was keenly interested in observing the natural world during his entire trip. I don’t mean to suggest otherwise. But nonetheless it is true that geology was both his focus and his job on the voyage. Of the twenty four notebooks we know about of Darwin’s, from this voyage, most of the written material is about geological observations.

The story of Darwin’s invitation to join Captain Fitzroy on the Beagle is a long, complicated, and fascinating one. You can read about it in Darwin’s Autobiography, and several scholarly works, as well as various fictionalized accounts. For example, there were issues with his father: Continue reading Charles Darwin Bicentennial- Beagle and The Voyage

Charles Darwin Bicentennial – A Tangled Bank

Last Darwin Post I gave you the famous “Tangled Bank” quote, in which Darwin links the concept of selection to the concept of ecology and thus derives “grandeur in this view of life.”

This is a theme of much of Darwin’s writing in The Origin, and in fact, the Phrase “Tangled Bank” shows up much earlier in the volume.

In the case of every species, many different checks, acting at different periods of life, and during different seasons or years, probably come into play; some one check or some few being generally the most potent, but all concur in determining the average number or even the existence of the species. In some cases it can be shown that widely-different checks act on the same species in different districts. When we look at the plants and bushes clothing an entangled bank, we are tempted to attribute their proportional numbers and kinds to what we call chance. But how false a view is this! Every one has heard that when an American forest is cut down, a very different vegetation springs up; but it has been observed that ancient Indian ruins in the Southern United States, which must formerly have been cleared of trees, now display the same beautiful diversity and proportion of kinds as in the surrounding virgin forest. What a struggle must have gone on during long centuries between the several kinds of trees, each annually scattering its seeds by the thousand; what war between insect and insect—between insects, snails, and other animals with birds and beasts of prey—all striving to increase, all feeding on each other, or on the trees, their seeds and seedlings, or on the other plants which first clothed the ground and thus checked the growth of the trees! Throw up a handful of feathers, and all must fall to the ground according to definite laws; but how simple is the problem where each shall fall compared to that of the action and reaction of the innumerable plants and animals which have determined, in the course of centuries, the proportional numbers and kinds of trees now growing on the old Indian ruins!

(Darwin, C. R. 1869. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 5th edition. Pages 86-87)

This is a fantastic example of Darwin’s breadth of interest and integrated mind. He makes explicit reference to the fact that selection is context dependant (“widely-different checks act on the same species in different districts”). He is explicit about the fact that chance is NOT the operative force in organizing nature (a fact that creationists seem to ignore when they speak of the unlikelihood of a tornado passing through a junkyard creating a Boeing 747 and hogwash). Continue reading Charles Darwin Bicentennial – A Tangled Bank