Comments on: I think we’re all biologists on this bus: two quickies

By: Bill

Bill — Mon, 14 Nov 2005 15:42:42 +0000

Anti-bacterial soap contains compounds that do, indeed kill bacteria more effectively. Sure, it may be true that some ways of avoiding selection of and exposure to dangerous bacteria may be better than others. But, who told you that killing bacteria not on your hands was a good thing? If people use small enough amounts of anti-bacterial products, so that they are not washing most of it off into the sewers, then they may be imposing a powerful but incomplete selection pressure for bacterial resistance. Remember that strong acid, high temperatures, and radiation and the harsh vacuum of space are all also very good at killing bacteria. Oh, wait -- there are bacterial species that survive quite handily in all those environments. Are they pathogens? Naaah. But they can do it. As my old colleague Ian Malcolm at SFI once said, "The history of evolution is that life escapes all barriers...."

By: Maynard Handley

Maynard Handley — Sun, 13 Nov 2005 01:40:12 +0000

It was my understanding (correct me if I am wrong) that anti-bacterial soap is not really a big issue because the mechanisms used by such to kill bacteria can be pretty damn blunt (and thus pretty damn difficult to evolve around), simply because soap is for external use, so a blunt mechanism that also (in some mild way) hurts human cells is OK.

Antibiotics, on the other hand, are much trickier because now you have to find something to attack that is specific to bacterial cells and not part of human cells.

Given the horrifying statistics I saw on some blog a month or two ago (37% of US doctors don’t believe in evolution, and let’s face it, probably a large number of those that do probably can’t put two and two together), the real issue here would appear to be the medical profession. A third possible villain (I don’t know enough about this) is antibiotics routinely pumped into animal food.
I suspect both of these are far more important than anti-bacterial soap.

By: Bill

Bill — Wed, 09 Nov 2005 03:27:28 +0000

You know, there was a day one autumn I recall vividly. It was a warm clear day, just after the first few cold days in fall that year, and I was walking along a quiet street on a campus, near a sports field. I noticed something odd, and looked up, and there was a silent, towering dust devil, maybe 5 meters across and 500 meters tall (what I could see of it). I saw it not because of the dust, but because of the leaves it picked up as it wandered along the ground.

It was slow, and I walked over to it and walked along inside the vortex for a while, until it hopped a fence I couldn’t cross. Very memorable, spending ten minutes or so in the midst of a gentle whirlwind.

Anyway: add dust devils and/or small whirlwinds to the umbrella hypothesis, and we have the “leaves from heaven”.

By: Branko Collin

Branko Collin — Wed, 09 Nov 2005 01:11:13 +0000

I think the only logical hypothesis is that leaves fall from heaven, but trees protect the ground from the leaves with their branches. After all, if you emptied a bucket of m&ms over my head while I held an open umbrella up, the m&ms would least likely end up directly in the space shaded by my umbrella. I think. I’ve never actually tried this. Do you think an experiment like that would be grant material?