Origins, Part 3
Definition of Life
Having addressed ages of the physical universe and the Earth, I now turn my attention to the topic of life. Some people conflate the origin of life and the theory of evolution, but they are quite different things. I will address evolution in the next article, but here we will talk about abiogenesis ("life from non-life") vs creationism.
Of first note is the definition of "life". Christians acknowledge spiritual life and physical life as two separate things. Thus, in one sense, we do not believe in abiogenesis, because Jesus Who declared Himself the Life1, and is the author of life2, is the One who created biological life. Thus, Life created life. But what is biological life? One might think that there is a good definition for this, but there are disagreements on certain things. For example, does a virus qualify as something that is living? Some scientists say "yes"; some say "no". Some futurists argue that an advanced artificial intelligence would qualify as living, though it would not be (exclusively) biological. Rather than give the definition of life from my college Biology text book, I'll give the following definition of biological life that I think would meet with the general agreement of most biologists today. A living organism is one which contains DNA that is directing the ongoing chemical processes in the organism's cell(s). Thus, a virus wouldn't qualify since its DNA or RNA is only for inserting into another living cell - not for carrying out ongoing chemical reactions within the bounds of a cellular membrane. But even the simplest bacteria would qualify as living.
However, it should be noted that the Bible refers to the "breath of life (Hebrew "naphash") only in terms of things that breathe. This would exclude plants and single-celled animals. Does that mean that the Bible is wrong? No, it just means that modern scientists define life (as I did above) in a more nit-picky way. Neither is less or more correct - just different. They happen to overlap when humans and animals are concerned.
Living Cells
Since we have defined that life is one or more cells, which contain DNA that directs ongoing chemical processes, we need to take a very abbreviated look at DNA, those chemical processes, and also the make-up of the cell. But before that, I need to explain proteins. A protein is a chemical compound made up of a series of smaller chemicals called amino acids. There are twenty amino acids used in the proteins that are used in biological systems. The specific amino acids that are used, the number of them, and the order they are joined together determine a specific protein. People generally think of protein as "meat", but meat is merely a substance that contains various proteins. There are thousands of known proteins and a practically infinite number of potential proteins that could be constructed from twenty amino acids. Different proteins serve wildly different purposes. Some are structural, such connective tissue. Some are enzymes (proteins that trigger operations). Some are poisons, such as snake venom. Some are used in tiny molecular "machines". Some serve multiple purposes.
We don't want the wrong protein used in the wrong place. For instance, an enzyme will be useless as a structural component. Not only do proteins have a specific chemical composition (the included amino acids), they also have a shape. Consider albumin, which makes up over half the content of egg whites. When raw, it is runny and transparent. If you heat it up sufficiently, however, it turns into a pliable white solid. Heat causes it to fold in a different way, altering its shape. Same protein, different shape with different characteristics. It turns out that the shape of a protein is important in many interactions in the body. Its shape allows it to fit lock-and-key with other proteins. Both the mechanical aspect and chemical reactions are important aspect of the bio-activity of a protein (that is, its affect on biological operations).
With the wide variety of potential proteins, producing the right ones is of utmost importance. This is controlled by DNA, a huge molecule that is essentially a recipe book of proteins for a cell to produce. How this process happens is basically as follows. A protein unzips a portion of the DNA (which is a twisted helix consisting of two backbones with amino acids linking them like rungs in a ladder). Another protein creates a copy from the DNA recipe. The copy is called RNA. Then the DNA is re-zipped. Another protein prevents the RNA from folding, which it wants to do due to chemical bonding forces. This is then carried away from the DNA to a place where it can be copied. It is moved via another protein that has two "legs" which literally walk along a microtubule that serves as a track leading to the "factory" that uses the RNA to construct the protein indicated by the RNA, folded in the correct way. The proteins are collected together in a bubble (called a vacuole) which is then carried to the cell membrane for release outside of the cell. That's a simplistic description - it is actually far more complex. And there are things we as yet do not understand. Such as, how does the cell "know" which proteins it needs to produce, how does it find the right spot on the DNA for the needed proteins among all the proteins defined in the DNA, how does it "decide" where to construct the microtubule transportation network inside the cell, etc.?
There are other essential aspects of a cell. There is a need for energy, which is generated by mitochondria (which are like complete cells in themselves), the need to dispose of waste products, and the need to recycle broken proteins. In other words, even the simplest cell has to have all these aspects to function as a living cell. It is like a miniature city containing factories, power plants, recycling centers, garbage collection and disposal, transportation systems, a multiple molecular machines that perform actions such as transporting things. Surrounding all of this is a membrane that protects the insides of the cell from external threats. The membrane is a two-layer wall enclosing the entire cell. If that were all it was, however, the cell would be completely isolated from its environment and would neither affect the environment or be able to take in the nutrients it needs to function. Thus, the membrane has various proteins embedded in it that serve as locks that the right external proteins can use to open a temporary portal into the cell. These are called receptors and different cells have different receptors, as well as some in common.
All of this self-contained city of activity is controlled by the DNA. Thus, biological life as we know it cannot exist without DNA. However, as noted with viruses, DNA in itself is not sufficient to make a living cell. All of the aforementioned components, working together, are necessary to have a living cell.
Scientific Concepts of Abiogenesis
To those looking for a naturalistic explanation for the origin of life itself, forensic science is required since no one was around to observe and describe the emergence of life. However, there is little to no modern evidence to latch on to for a forensic approach. Instead, scientists turn to theories of what the conditions of a young earth would have been. Again, we don't know what the conditions were, so this is entirely educated speculation. However, based on these theories, the idea of abiogenesis is that conditions were such that all the components of a simple living cell eventually came together over billions of years through chemical interactions. This is also called "chemical evolution", though I don't personally care for that term. It is environmental changes that result in natural selection of beneficial traits that enable an organism to survive and reproduce. However, until you have life, there is no reproduction and, thus, no natural selection. So the term "evolution" in regard to abiogenesis is misleading, at best.
As a simplistic summary, abiogenesis supposes a chemical "soup" containing basic building blocks, input of energy (from heat or electrical discharge), chemical reactions, and a long time period. This eventually results in the simplest living cells. A "simple" cell being one that exhibits all the foregoing components and operations, plus the ability to reproduce (which is another complex process). Scientists have experimented and postulated about what is the minimum genome for self-contained life and have come up with a couple hundred proteins that would be needed (I'm not sure if that also supports reproduction).
As I pointed out in a previous article, God could have accomplished the creation of biological life through naturalistic causes. So, even if one could prove chemical evolution, it proves nothing about God or His part in creation. However, looking deeper into the complexity of even "simple" life, one cannot imagine how such complexity could develop from a soup of chemicals - no matter how much time one is given. The appearance of life would have required several sequential miracles. Frankly, I find it requires far less faith to believe that God simply "zapped" life into existence than that He used several improbably circumstances to bring it about over time. But truth is sometimes stranger than fiction, so perhaps I'm wrong about that.
Why do I find abiogenesis so unbelievable? You must have all of the aforementioned parts of a cell together or there is no life. DNA without a means of replication, or RNA without a cell membrane, or a cell membrane without protein receptors - none of these things can be. If you leave out one single aspect, the cell dies - or never lives in the first place. Without a cell membrane to protect the inner workings of the cell, how does it generate the proteins needed for the membrane, for instance? The idea that these things randomly developed over time is also unsupportable. There is no selective pressure that would favor cells with these features over those that don't. Thus, every part of a cell would have to occur randomly. Plus all the random occurrences would have to come together randomly in just the correct way. Then we have the problem of what we call "irreducible complexity". Without the complex proteins to keep the RNA from folding in on itself as it travels from the DNA to the protein factories, proteins cannot be created. But that requires that the factories had previously created that very protein. Both have to exist at the same time or nothing happens. And this isn't the only example of mutual interdependence we find.
The complexity of DNA is also a problem. It essentially contains information in the form of recipes for proteins. How did the the minimum 200 protein recipes get encoded into DNA randomly? That isn't just creation of life from nothing, it is also creation of information from non-information. Plus DNA is rather complicated in itself. It is very unstable and easily damaged. So there are molecular "machines" made of complex proteins that repair damaged DNA in situ. During replication (cell division) there are proteins that verify that the copied DNA matches the original. There are proteins that must unzip (and re-zip) portions of the DNA. Second, if the DNA of a cell were stretched out in a line, it would be several meters long, so to fit into a microscopic cell, it has to twist up into a three-dimensional structure. If random, this could cause problems with obtaining recipes. So we find that the DNA's 3D structure is itself complex, with partitions into different "domains". Surprisingly, where the DNA strands cross each other, we find related proteins near each other, despite being separated linearly by thousands, or tens of thousands, of amino acid pairs in the DNA strand. Then there have to be start and stop indicators for each protein recipe. In multi-cellular creatures, DNA is even more complex, with epigenetics affecting things, and the mixing up of genetic material from two parent creatures. We've only begun to understand the amazing complexity of DNA.
Various experiments have been performed over the decades to try to simulate chemical evolution in the laboratory. There are some problems with this. As I mentioned, no one knows the original conditions of the planet, so - even if chemical evolution is true - how could they prove it is even possible if their theories of original conditions are wrong? Perhaps if they assumed different conditions, they might make better progress - because their progress has been disappointing from the perspective of the theory of Chemical Evolution. One experiment succeeded in creating what the scientists called primitive cell membranes. But all they did is create bubbles with two-layer lipid shells - a far cry from the membrane of a living cell which has proteins embedded in it to serve as "doorkeepers". Then there have been experiments that succeeded in creating the two simplest amino acids. However, the process couldn't have created the other 18 amino acids required for life. This isn't a matter of time either. They couldn't be created in any amount of time.
The idea held by most modern scientists is that given enough time, even the improbable can happen. Some call this "deep time". You've perhaps heard that given an infinite amount of time and an infinite number of monkeys typing on an infinite number of keyboards, that eventually the entire works of Shakespeare would randomly be created. This is the basic idea. But no matter how much time, the impossible cannot happen. Most of the amino acids will not come into existence no matter how much time occurs due to the fact that the ends of the acids chemical repel each other. In a living cell, these amino acids are created mechanically through protein factories. But protein factories require proteins that cannot be created chemically. Many of the needed chemical reactions require water, yet water molecules prevent those same reactions from happening. Everywhere we look, we see interdependent conditions that cannot come together naturally using the laws of chemistry. Even if we had every amino acid available, usable proteins are not guaranteed. Many of the required proteins for life naturally fold into shapes that make them useless for biological processes. The cell's protein factory is necessary to both combine amino acids but also to make sure the protein is folded into the proper shape.
But even if we could assume that, somehow, all the amino acids were available to combine randomly into various proteins that happen to be in the right shape, there are still problems. Since about 200 proteins are required for life, that means that the first living cell would have to have 200 proteins of the right type. Or rather, 200 different types of proteins. The cell would required hundreds or thousands of copies of each of these proteins at the same time. If we ignore the impossible chemistry, the first cell would require that enough of all of the random proteins would come together at the right time without any random proteins that would interfere with the operation of the required proteins. This cannot be accumulated over a long period of time because proteins break down over time. So the process would have to happen within a relatively short period - the cell couldn't slowly come together over millions of years. Would it be possible for the right proteins to come together assuming we had random protein generation somehow? One could possibly calculate the odds, and the time required. However, even secular scientists consider odds that are astronomically small to be equivalent to "impossible". Including the aforementioned problems, the possibility of the right proteins coming together to form the molecular machines, DNA, RNA, the selectively-permeable membranes, and everything else required for the simplest "life", qualifies as astronomically improbable no matter how much time you have. As you might imagine, I've only lightly touched on some of the problems with chemical evolution. You cannot "evolve" a living cell into existence.
The problem is so great that most evolutionists now avoid the issue of abiogensis, instead assuming that life already exists in order for evolution to occur. We'll address evolution in the next article, but believing in chemical evolution requires more faith than believing in a Creator. The only way I can conceive of something so impossible happening is if the Creator specifically manipulated it into being. While not denying that as a possibility, I find the most satisfactory explanation of the origin of life is that God simply willed (spoke) it into existence in an instant.