Sunday, May 13, 2012
But first, a quick reset.
In case I wasn't clear before, there is no question amongst scientists as to weather or not evolution took place, either in our own genetic past, or that of every other living thing on the planet. We know this because, contrary to creationists arguments, fossil records alone -though certainly not "complete*"- are enough to confirm that evolution is a real process responsible for the forming of all species, and almost certainly life itself. Modern genetic studies have gone even farther in mapping, not only the relation of all species to one another, but the points at which specific biological mutations led to their diversification; the point at which one genetic makeup changes (evolves) enough to become another. But in the monkey bill entry, I brought up the idea that evolution was not only a scientific reality of our biological past, but that it was still an ongoing process in the world today. One of the things that makes this, as well as the idea of evolution in general a hard fact for may people to accept, is that evolution happens too slowly in complex, long living organisms, to be observed in real time. But that doesn't mean it can't be observed at all.
Because of their rudimentary genetic makeup and brief lifespans, which can allow for the passage of thousands of generations in a relatively short amount of time, single celled organisms like bacteria, are invaluable in the study of evolution. The E. coli bacteria in particular, has played an integral role in it's study.
Arguably one of the most definitive and direct observations of evolution ever made, was published in the 2009, result of a research experiment conducted at Michigan State University. The experiment was conducted by Professor Richard Lenski, on a sum total of 40,000 generations of E. coli bacteria, grown over the course of 20 years. By the 20,000-generation midpoint, researchers discovered 45 mutations among surviving cells. Mutations, which, in accordance with the theory of Darwinian evolution, afforded those generations of the bacteria distinct survival advantages over their ancestors. One of the the most dramatic examples of the evolution of the bacterial colonies in Lenski's experiment, was one population of bacterias development of the ability to utilize a carbon source other generations and populations could not.
The Michigan state experiment is just one of the many examples of E.coli in particular, being used to directly study and observe the evolutionary process as it takes place, and there are countless other examples of similar experiments to choose from. A recent favorite of mine -What? How could you not know by now that I'd be the kind of guy who'd have a list of favorite scientific experiments?- was a result published just this year.
In an experiment lead by researchers Travisano and William Ratcliff , brewers yeast was successfully coaxed into evolving into a multi-cellular organism. The yeast was grown in flasks of nutrient rich broth. Those flasks were shaken once a day, and the yeast which sank to the bottom of the flasks was removed, leaving the free-floating yeasts behind. After just 60 days, the yeasts which clumped together had grown into permanent clumps of individual yeast cells, displaying all the tendencies associated with “higher” forms of life, including: a division of labor between specialized cells, juvenile and adult life stages, and multi-cellular offspring. Now, because the yeast was exposed to artificial pressures to grow larger, including artificial selection at the hand of the researchers involved, it could be argued that this was not a "natural" evolutionary process. But it does show that seemingly complex traits like multicellularity, can actually develop astonishingly quickly under the right conditions.
But let's be honest, all the bacterial experiments in the world, no matter how unambiguous the result, aren't about to convince the hardcore evolution denier; which is the only proper way to describe someone who chooses to ignore the factual reality of evolution, in case you disagree with my usage of the term.
* The incomplete fossil record is something of a logical fallacy. Not only because most creationists choose to ignore the existence of transitional fossils, but because it implies 1) That all the steps in the evolutionary process from point A to point B, have been identified. And 2) That such a thing could even exist, since, given that many creatures would not have left any physical evidence behind, it could not.