Wednesday, March 9, 2011

Evolution of Scientific Theory/Hypothesis: Lamarckian? (Ironic or just amusing?)

Random thought of the day (may or may not become a daily occurrence):

For those of you without a biological background, a primer. Evolution is the study of the development of new species from older species (ex. from ape-like beings to humans). During the development of evolutionary theory there were two competing theories. Both theories involve the transfer of traits from the parent generation to the next. Both theories also state that the accumulation of these changes/traits will eventually lead to the formation of new species. The two theories differed in where the traits came from. The first theory, largely discredited now, states that these new traits arose from an organisms own ability to change itself. A famous example of this would be the giraffe gaining its long neck via stretching. Giraffe-ancestors would not be able to reach foliage in high up places (they were vertically challenged), so they would stretch their necks. This self-inflicted change would be passed on to their offspring, eventually leading to the creation of giraffes. This theory was labelled as Lamarckian evolution. The second theory states that these traits originated among the population already and that environmental pressures would give individuals with certain traits an advantage and these traits would be passed on. While a famous example of this would be moths in Europe during the Industrial Revolution, I prefer to look at the evolution of antibiotic resistance in microbes. Many species of bacteria are susceptible to penicillin. If we take a large population of a species of bacteria and expose them to penicillin, you'll find that some of the bacteria will survive and form new colonies. In this case, the environmental pressure would be the antibiotics and the trait would be the resistance. This theory would be called Darwinian evolution.

Okay primer over, back to my story. I was reading an article about cancer and the article mentioned HeLa cells. I remembered what HeLa cells were, but I was curious as to any new research on them. Ironically, I came across a fairly old article (1991) that proposed that the HeLa cells had evolved into a new microbial species. This then made me think about evolution, and then about science itself when I came to the conclusion that scientific theories evolve in a Lamarkian manner.

Take a fictional scientific theory stating that liquid water makes aliens explode. With each new discovery the theory changes a little bit. At first it becomes liquid water makes aliens explode because they are made of lithium. In the end you have a theory about how alien physiology created a new flexible lithium. Now inspecting how this theory/hypothesis evolved, you see that with new challenges to the theory, the theory adjusts itself, becoming a new, slightly different explanation.

Looking into this further we are aware that sometimes there are competing theories that try to explain the same phenomenon. There are two outcomes to this. One, the theories merge and become a new theory (this would be akin to two species evolving into a single species [I can't think of a biological equivalent]). The second outcome would be that one of the theories is discredited. One could argue that this is textbook natural selection, but I disagree. In this case the theories adjusted themselves in different directions. The key here isn't the survival of the fittest concept but rather the origin of the differences in the theories. The theories may have started the same but they diverged by changing themselves. If the theories didn't start the same it is more akin to two different species competing for the same ecological niche.

Anyways, I'm not expecting, or even wanting the current scientific method to change. I was just amused by how scientific theories evolve in a way that is not parallel to biological evolution.

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