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asyouwish72 -> RE: More evidence supporting Theory o Evil-ution! (6/12/2008 4:32:14 PM)
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quote:
This experiment specifically reports the tendency of bacteria to turn into different species. Nothing about branching at all. ie bacteria A evolves and turns into....errr wait for it... bacteria B
This is a linear process not a branching one.
First, let me say that these guys came up with a very clever experimental design. My hat's off to them. With that out of the way,
The article does NOT talk about E. coli evolving into a new, distinct species. In fact, it takes pains to point out that the entire concept of "species" does not really work effectively on the level of bacteria.
The important thing to understand about this experiment, and how it relates to evolution in the natural world, is the idea of selective pressure. The environment presented to the bacterial populations in the test flasks was quite distinctly different in terms of nutrient availablity from those areas in which E. coli is normally found. Specifically, the food sources available were quite limited. This meant that initial cultures were not able to exploit their environment optimally, and opened the door to improvements via mutation. Turns out (as anyone with a passing interest in biology can tell you) that Darwin was right: the lucky few who ended up with a set of genes that improved their fitness won out, and came to dominate the population. It took a long time and it was a matter of chance, but the population changed into something that was better-suited to its new environment.
That's evolution. Game. Set. Match.
PS- As previously noted, the "sharks and crocodiles" argument is baseless. They have not changed becuase they have not had to- they are still optimized (more or less) for their environments. Nature sticks with what works.
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