3 - The Origin of Life Made Easy

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potholer5495,359 views
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When Bill O'Reilly asked Kirk Cameron to give his best shot in proving the existence of God, this is what he said:

The fact that a painting proves there must be a painter, the human body proves there must be a designer, because of its complexity and because of the information we can see down at the DNA level.

The problem for fundamentalists like Cameron is that this argument can be too easily flattened. In this video, I want to show what scientists have actually deduced about the origins of life. So let's start by putting the artist and painting myth to rest.

Why can't paintings paint themselves? Simple. Because they are made of chemicals that can't replicate themselves. Living matter, on the other hand, does contain a chemical that can replicate itself. Even if God made DNA, he doesn't need to intervene every time animals mate. The DNA does the job on its own. So the real question is, how did DNA appear? How did living matter come from non-living sludge? Here, again, fundamentalists need to drop a common argument that seems to be based on complete ignorance of a current scientific hypothesis, which is this:

[Scientists believe life just popped out of nowhere.]

Of course that's not what scientists believe. Life popping out of nowhere is no better a theory than life popping out of the hand of a deity. So what do scientists believe about the origin of life? Let's take this step-by-step.

The first step involves looking at the primordial Earth 4.7 billion years ago. There it is, mostly wet, very warm, and with an atmosphere composed of all sorts of gases: hydrogen, hydrogen cyanide, methane, and ammonia are among them. DNA is a long chain molecule made from just four different types of nucleotides, so the first question is, where did the nucleotides come from?

In 1961, a researcher called Juan Oro left hydrogen cyanide and ammonia to stew in an aqueous solution in his laboratory under conditions very similar to those that prevailed on the primordial Earth. Left alone, the solution produced adenine, one of the first four nucleotide bases that make up DNA. To make a complete nucleotide, these bases need to gain a sugar called ribose and a group of phosphates. Biochemists think they know how the phosphate group formed. They're now trying to find out how the ribose is attached.

Once nucleotides formed, the next step was to join together to make chains called polynucleotides. In the 1980s, researchers found that a clay called montmorillonite, which was abundant on the primordial sea floor and in hot pools of water on land, is the perfect catalyst for this process.

Some of these long polynucleotide chains, like ribonucleic acid, (or RNA), are able to make copies of themselves. The copies aren't always perfect. Mistakes creep in, but some imperfectly copied molecules would have been better adapted to the environment than others. These successful molecules continued to replicate and pass on their traits, while weaker or less well-adapted molecules would have broken apart.

As RNA molecules replicated themselves, they shared their environment with other chemicals that thrive in montmorillonite clay. One group called lipids have a natural tendency to clump together to form spherical structures called micelles. RNA molecules that attracted these lipids would, therefore, find themselves protected inside a micelle membrane. Because they were better protected, they better survived and replicated more successfully. There you have the first primitive cells. They look nothing like the complex cells we have today, and for a very good reason. Over 3.7 billion years, they've evolved. I'll tackle the subject of evolution in another video.

Over hundreds of millions of years, RNA grew more complex. The single strand became a double strand, and the better-adapted DNA molecule evolved. One of the differences between RNA and DNA is that DNA needs proteins to replicate itself. Proteins are made of amino acids, which are often called the building blocks of life.

So where did the first ones come from? No, there was no need for God. A number of experiments using montmorillonite have produced not only amino acids, but long chains of amino acids called polypeptides. Montmorillonite, it turns out, is a natural breeding ground for all kinds of complex organic chemicals.

It has to be said that this research is in its infancy, and current hypotheses are no where near as solid as the theory of evolution, which has been around for 150 years and has overwhelming evidence to support it. But the reality is a far cry from the idea that Scientists believe life popped out of nowhere. If God did, indeed, create life, then where did He come in? Step one? Step two? And why? If the chemical process can happen on its own, why would God need to intervene at all?

Before I go, I just want to look at a couple of other hoary, old arguments that have been used and which also show a complete ignorance of science.

[It is impossible for simple chemicals to form complex chemicals without intervention.]

Really? Just because creationist websites like to pass this myth around doesn't make it true. We know it's not true. Left alone, organic chemicals can and DO polymerize to form longer, more complex chemicals.

[But this goes against the 2nd law of Thermodynamics.]

Oh that sad argument. The fact is that the natural formation of replicating chemicals doesn't conflict with any of the laws of thermodynamics. People who make that argument need to read the law, because I suspect most of them have never done so and are just mindlessly repeating an urban myth that has already been debunked.

As I've said, we still have a lot more to learn about this process. Researchers know that there are many more intermediate steps that we haven't yet discovered. And when all of them are found, there will still be fundamentalists around to say, Ah, but you can't prove that this is how life started on Earth. No, we probably never will, but what we can say is if there is a natural process by which the first replicating molecules appeared on Earth, then we don't need to invent gods, goddesses, and other invisible deities to explain it. Ultimately, this isn't a guessing game. It's a detective trail.

Author's description [hide]
The video explains current ideas as to how life might have originated on Earth. The idea that inorganic mud can miraculously turn into cells is a claim made in the Bible and the Qu'ran, not science. What biologists are trying to do is understand how carbon-based chemicals combine to form nucleotides, the building blocks of replicating chemicals. The chemistry is complex, but it's starting to be understood, and it's not magical. 
   Please also see The Origin of Life - Abiogenesis by cdk007 which gives an excellent description on the latest hypotheses about cell formation.
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Thanks to potholer54 for providing transcript.

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