Saturday, November 11, 2006

Experimental evidence of evolution


For those who say that the theory of evolution is a belief just like intelligent design is a belief, here is another piece of evidence for you. The two species shown to the left are involved in a "red queen" antagonistic co-evolution race. The wasp feeds on the larvae of the house fly, and because wasps that eat more larvae are more likely to survive and have offspring, the population as a whole become more and more efficient predators. The fly on the other hand must develop defenses against these wasps. Those larvae that are unable to defend themselves against the predator will die and therefore cannot contribute any genes to the next generation. In sum while the wasps become more and more efficient killers, the flies get better at protecting themselves, thus the relative frequencies remain stable.

What happens though if you, for each new generation, take out, say all the surviving flies, that is, all the flies that were able to survive the attacks from the wasps, and instead introduce a new population of flies that have never encountered these wasps before? What happens is that virtually all flies are killed! The wasps have evolved by natural selection, but the flies have not. If you do the opposite and introduce naive wasps to flies that have had a chance to evolve, then the relative frequencies tilt to the advantage of the fly. The wasps starve to death because they cannot overcome the defenses that the house fly has evolved.

This experiment has actually been done, way back in 1963 by Plmentel and Al-Hafldh, and yet, there are still tons of people who claim that the theory of evolution asserts that all species were formed accidentally (not to mention all the Christians who firmly believes this is what the theory of evolution says). How is the process illuminated in these experiments chance? Please, someone explain that to me, I do not understand

2 comments:

GeneralERA said...

It's pretty simple. Natural selection is easily proven experimentally, and that's what Darwin observed. The actual "Origin of the Species" is where the debate lies. ID advocates and creationists dispute the plausibility of life arising from non-life, and the possibility of natural selection leading to extreme changes. While tightly controlled experiments have been done that have produced certain enzymes and proteins, there has not yet been an experiment that has actually created life from basic chemicals. Even if there were to be such an experiment, all it would prove is that people can create life, not that it can arise on its own. For that to happen, this abiogenesis would have to be observed naturally.

Dave said...

"How is the process illuminated in these experiments chance? Please, someone explain that to me, I do not understand"

What causes the mutations to occur that cause the flies to be better adapted to survive? What causes the mutations to occur that cause the flies to be more adapted to handle the flies' mutations? There is no intelligent agent involved. The surviving flies don't know what killed many of the last generation and even if they did, they couldn't encode that in their DNA to pass it on. Chance is the mechanism that drives mutations.

Isn't the whole process you described natural selection but not evolution? Did any of the original fly population have the traits that now keep the whole population alive? If so what we have observed is the limiting of the gene pool and the increase of flies that have the particular limited, though in this case beneficial, genetic makeup. This is not evolution. The loss of genetic information is de-evolution.