Sugars from space? Do they prove evolution?
To a chemist, a sugar is not just that sweet crystal added to coffee and tea. Rather, sugars are one family of chemicals containing lots of hydroxyl groups (OH) attached to a carbon skeleton (polyols). Sugars are vital components of life, e.g. the 5-carbon (5C) sugars ribose and deoxyribose are part of the skeletons of our information storage molecules, RNA and DNA respectively. Ribose is also an essential component of the energy currency of life, adenosine triphosphate (ATP). The 6C sugar glucose is a basic energy source for plants and animals, and they are joined in chains to form the cellulose of plant cell walls, as well as the energy storage molecules starch (plants) and glycogen (animals). Common sugar, sucrose, found in sugar cane and to a lesser extent in sugar beet, is actually a combination of two 6C sugars, glucose and fructose.
The ultimate origin of sugars is a huge problem for those who believe abiogenesis, the idea that non-living chemicals evolved into living cells without any intelligent input (see Q&A: Origin of Life). Abiogenesis has been such a difficult problem for the materialistic world view that various antitheists, such as Eugenie Scott of the so-called National Center for Science Education; and Richard Hutton, the producer of the Evolution series shown on PBS(USA) and SBS(Australia); try not to answer tough questions about abiogenesis. Instead, they claim it is not part of evolution, which is simply not true, given its common name ‘chemical evolution’. It has also been included as a part of the ‘General Theory of Evolution’, defined by the evolutionist Kerkut as ‘the theory that all the living forms in the world have arisen from a single source which itself came from an inorganic form.’1
But according to some recent headlines, abiogenesis has virtually been solved by the discovery of sugars in meteorites. Supposedly this shows that sugars could be produced in space, then rained down on Earth to be incorporated into the first organisms. But what is the correct story?
What was found?
Researchers led by Dr George Cooper of the NASA Ames Research Center in California analysed the much-studied Murchison meteorite and the less-well-known Murray meteorite.2,3 Both are a type of meteorite called carbonaceous chondrites, because they contain small nodules called chondrules. They are claimed to be the most primitive objects in the solar system, and the most likely to have organic (carbon-containing) molecules. They used a reliable technique called gas chromatography–mass spectrometry (GC–MS) to detect the different molecules, in the form of compounds with large silicon/carbon groups. They also studied the ratios of carbon and hydrogen isotopes, i.e. different forms of the same element. They found that they were enriched in the heavier isotopes 13C and 2H, which is consistent with an extraterrestrial origin for most of the molecules, rather than contamination from Earth.
They found evidence of lots of different chemicals with names unfamiliar to non-chemists, but in extremely tiny amounts. In fact, there was only one proper sugar found, and this contained only three carbon atoms. They also found a number of related compounds, the most abundant being the sugar alcohols, ethylene glycol (2C, better known as antifreeze), and glycerol (3C), but even glycerol made up only about 0.001% of the mass, and the other compounds were far less abundant. There were none of the sugars familiar to most people.4 The fact that these sugars are not common in living organisms is good evidence against biological contamination from Earth.
The researchers have proposed several possible ways these compounds could have been produced, including the ‘formose reaction’ starting from formaldehyde, which itself might have been formed from carbon monoxide and hydrogen.
The real science stops here with the last section, and as always, creationists dispute no observations made by evolutionists; i.e., we agree that the meteorite does contain organic compounds, probably of extraterrestrial origin. The difference is how we interpret the observations.
What should we think?
The ‘Big picture’
- The most important point to remember, more important than the chemistry, is that both creationists and evolutionists have biases. For the people who performed the research, the Nature editors, and the journalists who reported the results, the question was not ‘Did life evolve from non-life?’ Neither were they trying to find evidence to support either ‘yes’ or ‘no’. Rather, before even adducing the evidence, they have already made up their minds that the answer is ‘yes’—somewhat along these lines:
‘Well, of course life evolved from non-life, because we’re here! … What’s that you suggest … that life may have been designed? You just don’t understand the rules of science. A designer is not part of science, even if the evidence supports that, as Dr Scott Todd pointed out. As Dr Richard Lewontin said, we must only allow materialistic explanations, because we can’t allow “a divine foot in the door”.’
This faith commitment has been noticed even by non-creationists such as the information theorist Dr Hubert Yockey, as shown by this quote.
- This bias produces much wishful thinking, where every trace of organic molecules found is taken as evidence for chemical evolution. As will be shown below, this is contradicted by science. The wishful thinking occurs not only in the popular media, but also in the Nature Science Update commentary:
‘The findings therefore support a growing realization that, even in the frozen depths of space, lifeless chemistry can arrange the elements into molecular forms well along the road to primitive life.’5
Even the acting director of astrobiology and space research at Ames, Kenneth Souza claimed:
‘This discovery shows that it’s highly likely organic synthesis critical to life has gone on throughout the universe. Then, on Earth, since the other critical elements were in place, life could blossom.’6
But while Cooper himself was enthusiastic overall, he did sound a note of caution about the research:
‘What we found could just be interesting space chemistry, and polyols could be just relatives of the compounds that actually gave rise to early life.’6
I agree that it was ‘interesting space chemistry’, and actually have no problem with the researchers’ suggested production mechanisms such as the formose reaction, but this doesn’t mean that it was relevant to chemical evolution. Cooper concluded that more research was needed to learn whether this research was significant.6
- One of the key evidences against contamination, the presence of non-biological sugars and their relatives, also seems like good evidence against chemical evolution. That is, that natural processes tend to produce gunk with little relevance to life.
- The amounts of these chemicals were tiny—far too low to contribute to biological processes. So this can also be interpreted as evidence against chemical evolution, by showing that under truly natural conditions (as opposed to unrealistic laboratory simulations), only trace amounts of these compounds are formed.
- The wide variety of compounds in itself counts as evidence against chemical evolution. Most of the alleged prebiotic simulations use pure compounds, and even then, the results are meagre, so how much worse would they be with the contaminated gunk produced in the real world?
- Sugars are very unstable, and easily decompose or react with other chemicals. This counts against any proposed mechanism to concentrate them to useable proportions. See Origin of Life: Instability of building blocks.
- Living things require homochiral sugars, i.e. with the same ‘handedness’, but these ones would not have been. See Origin of Life: The Chirality Problem.
- Even under highly artificial conditions, the result of intelligent investigator interference, there is no plausible method of making the sugar ribose join to some of the essential building blocks needed to make DNA or RNA, let alone into RNA or DNA themselves. Instead, the tendency is for long molecules to break down into their building blocks. See Origin of Life: The Polymerization Problem and The RNA World: A Critique.
- Even DNA or RNA by themselves would not be life, since it’s not enough to just join the bases (‘letters’) together, but the sequence of the letters must consitute meaningful information. The information depends on the letter sequence and this sequence is not a function of the chemistry of the letters. Information: A modern scientific design argument.
- Even this letter sequence would be meaningless without elaborate decoding machinery to translate this into amino acid sequences. I.e. the DNA stores the instruction code to form the enzymes and structural proteins needed for life. Unless the decoding machinery already existed, those instructions can never be read. Similarly, this article would be useless to a non-English–speaker, who lacks knowledge of the code of the English language to convert alphabetical letter sequences into concepts in the mind (information). See Self-Replicating Enzymes?.
Once again, this teaches us that we shouldn’t rely on pro-evolution newspaper headlines. As always, even if they have reported the scientific observations correctly, the observations must be interpreted. As shown, it is more plausible to interpret them in a Biblical creationist framework and apply well-attested chemical principles. The result is that not only do the observations provide no support for chemical evolution, they are actually further evidence that chemical evolution is based on blind faith rather than fact.
- Kerkut, G.A., Implications of Evolution, Pergamon, Oxford, UK, p. 157, 1960. He continued: ‘the evidence which supports this is not sufficiently strong to allow us to consider it as anything more than a working hypothesis.’ Return to text.
- Cooper, G. et al., Carbonaceous meteorites as a source of sugar-related organic compounds for the early Earth, Nature 414(6866):879–883, 2001. Return to text.
- Sephton, M.A., Life’s sweet beginnings [perspective on Ref. 2], Nature 414(6866):857–859, 2001. Return to text.
- For those trained in chemistry, they found a number of sugars and other types of polyols, e.g. sugar acids and sugar alcohols. The difference is that sugars proper are polyhydroxy aldehydes or ketones, while alcohols have all hydroxyl groups, and acids have a carboxyl group. In fact there was only one sugar proper, dihydroxyacetone (3C). The most common compounds were the sugar alcohols ethylene glycol, and glycerol (3C). The amounts were minuscule, with only 160 nmol/g of glycerol. But even this tiny amount is more than twice that of the most abundant amino acid found in the Murchison meteorite. The 4C sugar alcohols erythritol and threitol were only 1% as abundant as glycerol. The 5C sugar alcohols such as ribitol and its isomers were even less abundant, while the 6Cs weren’t actually seen but the researchers claim they might have been present in bound form. Sugar acids were also found, with the 3C glyceric acid about half as abundant as glycerol, and again the higher-C acids far less abundant, but more so than their corresponding alcohols. Some deoxy sugar acids were found, where a hydroxyl group is replaced by a hydrogen. Deoxyribose is the most significant deoxy sugar proper, since it’s a component of DNA. Return to text.
- Ball, P., Shooting stars sugar coated: Meteorites could have sweetened the earliest life [commentary on Ref. 2] ,Nature Science Update, 20 December 2001. Return to text.
- NASA Scientist Finds Some Meteorites not Sugar-free, 19 December 2001. Return to text.