Thursday, February 19, 2009

Creationists are also wrong about abiogenesis

Evolution explains how the diversity of life that we see on Earth arose from a single common ancestor. But it doesn’t explain where that first common ancestor came from. The name given to the study of the origin of the first living thing from non-living things is called abiogenesis.
Most scientists believe that life came from non-living chemicals through a process not fully understood at this time. Strictly speaking that research is not relevant to evolution itself. The common ancestor of all life could have come from any source – chemicals, outer space, an alien planting life on Earth or from a supernatural act of God – and nothing in evolution would have to change. Not a single word in Darwin’s book On the Origin of Species would change if any of those alternatives was proven to be the source for that first life. Research in abiogenesis is even done by a different group of scientists than is the case for research into evolution. Abiogenesis research is primarily done by organic chemists. Evolutionary research is done primarily by biologists.

Of course there is a close relationship between evolution and abiogenesis. You could even argue that the first living thing was the first thing that could evolve. Effectively the ability to evolve could be used as the first test of when something is actually a living thing.
The real reason why creationists like to raise this subject is because scientists admit that they don’t have an answer yet as to how life first arose. If creationists start talking about abiogenesis they will get the honest answer, “I don’t know” from scientists. On the other hand, scientists have explanations for just about all aspects of evolution itself. The “God of the Gaps” argument so often used by creationists is more persuasive in the case where there is no specific alternative suggested by scientists.

Creationists often insist that abiogenesis was falsified by Louis Pasteur. That is not the case.

Before Pasteur, many people thought that living things arose from non-living things all of the time. If you leave a piece of meat on the ground, you will see things like fly maggots come out of that meat. They’re alive. The general impression was that those maggots arose naturally from the dead meat. This process was called “Spontaneous Generation”.
Pasteur falsified “spontaneous generation”. He showed that fly maggots actually came from germs present in the air that came from living flies. In other words, they can only come to life if there is pre-existing life.
That is not the same thing as abiogenesis.
Fly maggots are relatively large organisms (you can see them with the naked eye). Everyone believes that the first living thing was at most a single cell. Single cells cannot be seen with the naked eye. The processes would be completely different and the end results would be completely different as well. It is interesting to not that even Pasteur felt that abiogenesis was possible. He believed that he had not falsified that idea.
Here’s what Pasteur said[1]:
"Life is the germ and the germ is life. Now who may say what might be the destiny of germs if one could replace the immediate principles of these germs (albumin, cellulose, etc) by their inverse asymmetric principles."The solution would constitute in part the discovery of spontaneous generation, if such be in our power."
Note the phrase, "...the discovery of spontaneous generation..." (The word ‘abiogenesis” hadn’t been invented yet.)Pasteur's words were first written in 1883 but not published until 1922 because the political powers were very conservative when it was first written.
Scientists are making excellent progress towards finding solutions for how the first living thing appeared. But it is a very technical subject. For those interested, Wikipedia and other Internet resources can provide a great deal of information about the state of the research into abiogenesis.
It is worthwhile to discuss the single most famous experiment related to abiogenesis. Creationists are prone to mention it when they are talking about this subject. That experiment is called the Miller-Urey experiment.
In 1952, two scientists (named Stanley L. Miller and Harold C. Urey) attempted to duplicate the early Earth’s environment in order to see what sorts of building blocks for life they could find. They published their results a year later, in 1953.

Their experiment is described by Wikipedia like this[2]:
"The experiment used water (H2O), methane (CH4), ammonia (NH3), and hydrogen (H2). The chemicals were all sealed inside a sterile array of glass tubes and flasks connected in a loop, with one flask half-full of liquid water and another flask containing a pair of electrodes. The liquid water was heated to induce evaporation, sparks were fired between the electrodes to simulate lightning through the atmosphere and water vapor, and then the atmosphere was cooled again so that the water could condense and trickle back into the first flask in a continuous cycle.
At the end of one week of continuous operation, Miller and Urey observed that as much as 10–15% of the carbon within the system was now in the form of organic compounds. Two percent of the carbon had formed amino acids that are used to make proteins in living cells, with glycine as the most abundant. Sugars, lipids, and some of the building blocks for nucleic acids were also formed."

“Amino acids” are complex, organic (i.e. carbon-based) molecules that are very important in biochemistry. They are critical to life and play a variety of roles in metabolism. Proteins are combinations of multiple amino acids. The most well-known amino acid is probably monosodium glutamate (also called MSG) used in food preparation. The complexity of the molecules produced by this experiment and the relative ease with which they were produced was eye opening.

In the last half-century the standard view of what the early atmosphere was like has changed a bit. Creationists are fond of pointing that out and they claim, therefore, that the results of this famous experiment are now irrelevant. But similar experiments have been performed with artificial environments matching more recent views of what the early atmosphere of Earth was like and similar results have been achieved.
Creationists insist that complex organic compounds leading to life can’t happen by chance. But scientists are not claiming that the first life happened completely by chance. Large complex molecules form because of the nature of how atoms interact with each other. Even water is a combination of hydrogen and oxygen that is more complex than either hydrogen or oxygen by itself. But water is still something that will nearly always form with those two atoms are mixed together.
All of the available evidence indicates that life appeared on Earth quite soon after the Earth was formed. It could very well be that life in an environment such as that on Earth is inevitable and unavoidable.
It is even possible, though admittedly unlikely, that new life is continuing to be created today. The problem is that there is now pre-existing life.
If a new, microscopic life form was created thirty minutes ago near some warm water vent in the depths of the ocean, then that new life form was probably eaten by a bacterium fifteen minutes ago. By definition, that would not have been a problem for the very first living thing.
Of course the fact that science doesn’t have a current explanation for how life came about through natural processes doesn’t mean anything except that the solution to this problem is complex. I like to point out that Native Americans were similarly perplexed when asked to provide an explanation for how those very complicated things that we call “thunderstorms” came into existence. They decided that an intelligent being must be responsible. They called that being the “Rain God”. We no longer consider a “Rain God” to be necessary. We have a naturalistic explanation for what causes thunderstorms. We can even predict them (with imperfect but improving accuracy).
That is the fundamental flaw with the “God of the Gaps” argument, one that we have discussed previously because it comes up so often when debating creationists. The basis of the argument is that if we don’t have an answer right now, then we will never have an answer and God is the only possible solution.
That argument has failed time after time after time. It is still not valid.
It never will be valid.
[1] The Evolution Wars by Michael Ruse, Rutgers University Press, New Brunswick, New Jersey, 2001, p. 153
[2] http://en.wikipedia.org/wiki/Miller-Urey_experiment, referenced on January 15, 2009

2 comments:

  1. "He showed that fly maggots actually came from germs present in the air that came from living flies."

    He did? I thought maggots came from fly eggs laid on the meat.

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  2. You err in your description of Pasteur's experiments. That fly maggots cannot arise through "spontaneous generation" was proven by the Italian Francesco Redi in 1668. Pasteur's experiments showed that microscopic life, including bacteria and other single-celled organisms, cannot arise through spontaneous generation. In other words, he took the work of Redi and others into the microscopic realm.

    Did he disprove abiogenesis? No. But you should keep your facts straight or you make this side of the debate look pretty dumb.

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