[ha8o8le]

I have a friend who is somewhat of a "evolution denier" (he's not religious and actually very intelligent). I was thinking about this from his perspective and would like someone else perspective.

"On human terms, the LTEE generations span the equivalent of well more than a million years of human evolution."

Haven't we evolved a lot more in 68,000 generations than the bacteria have? Or put another way, all the bacteria has done in this time period is go from consuming glucose to citrate, nothing else in its shape, structure, etc. So how did humans and other creatures evolve so much over 68,000 generations?

I am 100% on board with evolution, I'm just curious about this. This is only 6-7 times more generations than when humans split from chimps (quick google search said 6-7 million years ago).

Is it because we have way more interaction with our environment and these bacteria are just in a little petri dish? Sounds likely.

Has anyone ever heard of people questioning evolution? I think he was saying something about how impossible it would be to have every single thing we see in nature be pre-written in DNA - it has just been all expressed in genes over the millennia through natural selection.

[Scaevolus]

Sexual reproduction allows beneficial mutations to spread and recombine in a population much faster than asexual reproduction (yes, e.coli has conjugation, but it's nowhere near as powerful). A complex trait might require multiple mutations to support it-- a gene pool that's constantly mixed by sexual reproduction will have much higher chances of the combination arising than with asexual reproduction.

You can observe the same thing in genetic algorithms, where crossover ("sexual" reproduction / mixing of two candidates) is often performed because it creates more viable offspring than simple cloning with mutations.

[whiskyant]

Because we and other mammals are much more complex lifeforms than bacteria, and likely have systems that help us adapt/evolve faster.