Evolution & the Origin of Life

I've been thinking a bit about this topic lately. All you have to do is spend a little time browsing the internet to find the wildly varying information available. From researchers publishing their latest breakthroughs, to supporters of intelligent design offering supposedly scientific counterpoints, and everything in between. Honestly, it can be pretty confusing to those unfamiliar with the subject and downright frustrating to those who feel passionate about the issue.

I am not an expert. I might sometimes talk like I am, but I have no degrees or formal training on the topic, save for a year in college studying molecular biology (when that was my major). I'm not claiming to know anything absolutely, and quite frankly, I feel more comfortable when people concede a lack of perfect knowledge. For me, one of the strongest ideals of science is that it recognizes that data may someday appear that challenges even our most fundamental understanding of the way things work. Theories are only as certain as the data they describe, and their predictive power only indicates a reasonable confidence in their conclusions but never absolute certitude.

That certitude which exists in the minds of supporters of religious explanations for the origin of life (and everything else) is actually a weakness. It may seem counterintuitive, but this sense of an absolute truth that can be fully known prevents the believer from acknowledging new information that, though it may strongly contradict his belief, is strongly supported by objective evidence. If a believer could absolutely be shown to be wrong (not that I'm saying that can be done), I'm pretty sure he would still deny the evidence, because his belief system does not allow for the acceptance of such evidence. If, however, a scientist could be shown absolutely to be wrong (which is possible and has happened many times), she would simply have to reassess her understanding of that data and would have to offer an alternative theory that doesn't just account for this new data, but is highly predictive of it.

That is the strength of science. It is not a house of cards that relies on every theory it puts forth being true to hold it up. Science is more like a clay sculpture that can always be refined to a more accurate representation of reality, though perhaps never a perfect duplication of it.

To some degree, the intelligent supporters of creationism or ID recognize that it is impossible to argue against science without science, so they try to incorporate science into their explanations and refutations, confident that their assertions are a death knell to science. This is amusing because if you could prove the scientific method was faulty by using the scientific method, wouldn't that indicate that the process you used to prove it was faulty was, itself, faulty? This is a paradox of the same order of the statement "this statement is false". Fortunately, no such paradoxical proof has ever been offered, and I'm fairly sure that no such proof exists.

Instead of attacking the methods of science, creationists and ID'ers attack the data by cherry picking some data of their own. They often present physical evidence that might be interpreted in such a way as to support their beliefs, but ignore other evidence that refutes it or alternative explanations for their supposed evidence. Probability is also a favorite tool, as it is easily manipulated to achieve results that could support any number of viewpoints.

For example, many creation "scientists" boggle at the odds they calculate for the random creation of life. Their argument goes something like this:

"In the simplest known organism, there are about 5,000 genes. These genes must be in a certain configuration for that organism to exist. If you do the math, you find that there are 4.8 x 10⁵⁰ possible arrangements of those genes. Hence, the odds of that particular strand of DNA forming are 1 in 480,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000."

Wow, that number sure is impressive when you write out all the zeros. When you consider that the best estimates of the number of unique species on the Earth are about 10 million (and there may well be significantly more), it seems staggering to suggest that all that happened by chance.

Well, sure. Ok. If one were to suggest that at some instant in the past, atoms suddenly arranged themselves in the perfect configuration to build E. Coli bacteria, I would demand some pretty compelling proof. If you then went on to tell me that this happened randomly, I would probably walk away thinking you were crazy.

This is one of the major disconnects in arguments between evolutionists and creationists. Oftentimes, creationists go into a debate with an idea about what the evolutionist believes that is so far removed from reality, one can hardly blame them for questioning it. In fact, any evolutionist who believes that lightning struck a puddle of various chemicals, which then arranged itself into a perfect DNA molecule, is ignorant to the process proposed by most scientists.

It is important to note that, while we don't understand all of the processes involved in DNA or how it came to be, there is nothing in the structure or function of DNA that suggests it is defying the laws of chemistry. There are no remarkable compounds that just shouldn't be there, there are no chemical combinations that are impossible according to our current understanding.

That said, it is not absolutely impossible for these processes to have happened by chance. These staggering numbers that creationists offer (which I will demonstrate are misleading) still mean that it is possible, though highly unlikely by their numbers, that such things would have happened by chance. If you can prove that the chance that something occurs is not zero, you have just proved that it is possible.

Consider, for a moment, the following text: q@0oDt61m^eIDy%ag#eV4ivpws)h9r.

This text is a random string of 30 symbols from the set of all lower and upper case letters on a standard US keyboard as well as the numbers 0-9 and all the alternate symbols on those number keys. That means that any one of those symbols in that string has a 1 in 72 chance of being chosen at random (26 upper case + 26 lower case + 10 numbers + 10 symbols). That means that the odds of randomly typing that specific string of 30 characters is 1 in 5.25 x 10⁵⁵.

Wow! That's even less likely than the odds that the 5,000 genes in E. Coli bacteria just randomly flying together! And yet, there it is. It happened. Is it a miracle? No. Granted, that string of 30 characters doesn't mean anything, at least, it isn't intended to mean anything. Similarly, genetic code was never "intended" to mean something. Life didn't form based on chemistry's intentions, just the laws that govern it. That distinction is important because creationists need to think that the complex chemical reactions that are involved in life are somehow more special or remarkable than the thermonuclear reactions that power stars or the complex system of gravitational interaction that comprises a galaxy. The only remarkable thing about us is our ability to reason about whether or not we are remarkable.

Regardless, no reputable scientist is arguing that those 5,000 genes of E. Coli just suddenly assembled. Instead, scientists propose the very reasonable suggestion that on the early Earth, where organic compounds (those containing carbon and that are necessary for life as we know it) were in abundance and bombarded with all kinds of possible energies, from ultraviolet solar radiation to the still cooling planet's internal heat, assembled into more complex molecules over time. This is merely chemistry. One can perform experiments with chemicals thought to be in existence in early Earth and easily create amino acids, which are again a crucial part of life on this planet.

Over the course of probably geologic time scales, chemical reactions with organic molecules were happening simultaneously all over the Earth. In one of these reactions, the result ended up being some kind of molecule that was capable of replicating itself to some extent. There is nothing magical about this, nothing that requires supernatural explanation. Within the context of the laws of chemistry, it is perfectly possible for a molecule to exist that is able to replicate itself within a solution of its component parts. This self-replicating molecule was the precursor to our DNA.

There are numerous theories as to how DNA may have ended up within the nucleus of a cell, or within any part of a cell, but I will leave readers to investigate those on their own. If you haven't agreed with me thus far, you won't agree with any of the stuff that comes after. ID proponents often start with DNA in their arguments, especially because of the impressive probabilities against abiogenesis that can be derived (and exaggerated), so I thought I'd start there too.

Another favorite supposed science "gotcha" is the infamous and inviolable second law of thermodynamics. Specifically, this law states: The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.

It is the more general interpretation of this law, however, that creationists jump on. That interpretation states that the amount of order in any system will reduce over time rather than increase, unless there is some external force that acts to increase it. It should be pretty clear why this seems so significant to those who seek to prove that life was created by a divine intelligence.

The argument goes like this: A pocket watch is a highly ordered state of matter. It contains several tiny gears, cogs and springs, all perfectly suited to a specific purpose. If one were to come upon a pocket watch on a tree stump in the woods, it would be absurd to the highest degree to assume the pocket watch had assembled through some sequence of random events, especially if its discoverer knew about the second law of thermodynamics. The most logical conclusion, given the evidence, is that the pocket watch had an intelligent creator who cleverly crafted the watch with his own hands.

On the surface, that certainly seems reasonable. The parallels between a pocket watch and a living creature seem clear in this context. Living beings are also made up of many meticulously integrated parts that are perfectly suited for functioning in their native environments. If you remove one of its fundamental parts, it will cease to function (or at least cease to function as well as it once did).

So, what could possibly be wrong about this analogy? Furthermore, if the random assemblage of a pocket watch would be a violation of the second law of thermodynamics, then why isn't the random assemblage of a living creature? Well, keep in mind that what science claims about life is hardly random. Again, science believes that life originated via deterministic chemical processes, not that chemicals randomly combined in impossible ways. A pocket watch does not function through chemical processes. This is a pretty important point because there are no laws of chemistry that we know of that would govern a reaction that would result in even a single gear or cog in a pocket watch. Through non-chemical means, the natural formation of any part of such a watch in probabilistic terms is far less likely, by orders of magnitude, than the odds of a natural chemical reaction resulting in the precursors of DNA, which through natural selection evolved into increasingly more complex structures resulting in living cells.

So what of thermodynamics? Isn't a living creature a more ordered state than a pile of the same atoms sitting on the ground? How would one propose to explain that living things appear to violate the second law? For starters, let's revisit that pesky law:

The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.

Notice how I highlighted the word "tend" there. What the second law is referring to is a statistical reality that may not represent specific instances within that isolated system. Rest assured, over the course of time, the second law will result in an even distribution of entropy throughout the universe. That is, of course, unless the force of gravity in the universe is strong enough to overtake our expansion, but that's a whole other conversation.

Now, that last paragraph might seem like hand-waving. Verbal prestidigitation to allow for decreased entropy in living systems on a technicality. Well, if you think that's a poor explanation, you're right. The truth is, we don't need such technicalities to explain the supposed decreased entropy of a living system. This is true for two reasons.

First, even if a living system represents a higher state of order than a random pile of the elements that make it up, there were plenty of sources of energy that were around to be added to the system on ancient Earth. The planet was significantly less hospitable to modern life as we know it, but it was a boon to the chemical reactions that would give rise to life. Solar radiation, geothermal activity, cosmic rays, lightning and fiery impacts from the debris that littered the early solar system, just to name a few. Any or all of these sources could have provided significant energy to the chemical system that preceded life. This might suggest that life is one of the results of the entropy in the solar system moving toward equilibrium.

Second, consider for a moment some properties that all living things share. One of the fundamental properties of all life is a metabolism. All organisms must expend energy to perform the tasks of living, and so must obtain that energy from somewhere. Metabolism is the process by which organisms extract energy from their surroundings. We eat food and our body breaks that food down chemically to provide us with the energy we need to live. The most important thing about this system is that an organism's metabolism converts chemical energy into other forms of energy that are dissipated back into the environment, creating more disorder than the order required for a living thing to exist.

Just think about that. Simply by sitting there, your body is generating 98.6 degrees of heat by breaking down the food you've ingested and providing energy for respiration, circulation and all the other autonomic functions of your body. That heat is energy that radiates into the universe and heats it up. Even at rest, you increase the entropy in the universe every second. This energy exchange happens at all levels of life, and it is the crucial element to answering whether or not life violates thermodynamics.

With the points covered in the above paragraphs, it is pretty easy to demonstrate that life as a chemical process could have certainly arisen on ancient Earth without any direction from a greater intelligence. Once a molecule forms that can crudely copy itself, it is trivial to show that variation would have given rise to natural selection, which would have resulted in a more robust molecule. Further interactions with the environment and possibly ongoing chemical reactions would have gotten the ball rolling toward something we would consider life. All that would have been necessary from that point forward was time.

What really amazes me is that this whole process is stunning, a beautifully entwined confluence of physics, yet those who are opposed to these ideas seem convinced that science is somehow reducing life to something empty, hollow. The explanations of science don't allow for a soul or a divine creator, and this somehow lessens life's beauty and significance. Having an omnipotent being will into existence the diversity of life, fully formed, makes for great mythology, but it is truly awe-inspiring to know that the laws of physics alone are sufficient to account for all the wonder that surrounds us.

Pale Blue Dot

Sometime in the first half of 1990, as the Voyager 1 spacecraft hurtled beyond the edge of our planetary system, it spun around to take one final photo of the place from whence it had come, perhaps never to return again. Actually, Voyager 1 took several images in an attempt to capture a snapshot of the entire planetary system as each world orbits the sun. One of these pictures in particular, however, stands out as perhaps one of the most awe-inspiring and humbling images ever captured in the entirety of human civilization. It was entitled "Pale Blue Dot" by the man who campaigned to have the picture taken and who, in 1980, formally introduced the world to the "Cosmos". That man was Carl Sagan, astronomer, author and arguably the greatest contributor to our common understanding of the universe in modern history.

Sagan's words reflecting upon the significance of the "Pale Blue Dot" have been quoted and paraphrased many times. One wonders if it could ever be said better than this:

"Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam."

The sheer sense of humility inspired by such musings is chilling, and yet we should also be reminded of what we don't see beyond the confines of that photo. The image shows us as a part of the much larger grandeur of the universe. Granted, it is a very small part, but it is still a part. Carl Sagan also said, "We are a way for the universe to know itself," and while the universe may not have planned us for this purpose, or even planned us at all, I think we should rise to that challenge. This picture of a minuscule Earth sparkling in a ray of light is just a glimpse of the amazing perspectives that await us as we strive to meet that challenge.

To know the universe is a pretty enormous undertaking. We're making some strides, but we still have quite a way to go. Voyager 1 was launched in 1977 and took about 12.5 years to travel to a point where it would be about 6.1 billion kilometers from Earth, the distance from which the "Pale Blue Dot" photo was taken. A distance of 6.1 billion km is pretty far when you consider the distances we typically travel on the Earth, but on a universal scale, it isn't even a drop in the bucket.

Consider these points:

The universe was recently estimated to be 156 billion light years wide. As many of you probably know by now, a light year is the distance light travels in a single Earth year. Since light moves incredibly fast (a bit under 300 million meters a second), to say 156 billion light years definitely sounds like a lot, but words like "light year" and "billion" are simply words that we use to make it more convenient to talk about distances and numbers most humans couldn't even imagine. For the sake of demonstration, I am going to try to stop using these words to give you a little better idea of how mind boggling these numbers really are. My standard measurements will be in kilometers (km) and meters (m), admittedly abstractions themselves.

If the universe is 156 billion light years wide and there are (get ready) 9,500,000,000,000 (that's 9.5 trillion!) kilometers in just one light year, that means that the universe is 1,482,000,000,000,000,000,000,000 (1.5 septillion) km wide! Looking at the distance at which the "Pale Blue Dot" was taken, which was probably about 6,054,558,968 km (give or take a few million km), we can do some simple math to figure out how that compares to the universe.

*doing calculations*

That means that the distance at which Voyager 1 snapped that picture was 1/242,950,819,672,131^th of the total diameter of the universe. To put that into perspective, if the width of the universe were 1 meter, the distance from Voyager 1 to the Earth in 1990 would be about .00000000000000412 meters. The shorthand for this tiny distance is 4.12 femtometers, which is about the diameter of an atomic nucleus (depending on the atom). This calculation, comparatively, reduces the Earth to a size smaller than a proton or neutron, probably smaller even than a quark.

While this comparison seems to relegate us to some insignificant proportion of the universe, that's only true looking down on this tiny blue speck from afar. If we instead look outward at the vast reaches of our universe, we see that there is so much yet to discover. We are travelers on a quest to answer every question that can be conceived. The universe offers us no shortage of opportunities to drive and satisfy our uniquely human brand of curiosity.

It's not going to be easy. Many things stand in our way, the most perplexing being the universal speed limit, the speed of light. Even significant fractions of the speed of light seem difficult to fathom given our understanding of relativistic speeds and the current level of our space travel technology. Even at the relatively impressive speed that Voyager 1 shoots out of our solar system, it is still only moving at 1/18,000^th the speed of light. We're going to have to come up with something a lot faster than that if we're going to explore even the closest corners of our interstellar neighborhood. I believe, however, that we are propelled by such an intense need to know, we will find some way to overcome these obstacles. Far in the future, when the intelligent descendants of the human species look back on this pale blue dot, I hope they will look on it with fondness as the starting point of the incredible journey that brought them to every corner of the galaxy and maybe, just maybe, to their first steps into the larger universe.