Evolution: Not only the fittest survive page

[Bunnyfoot]

Interesting study on bacteria and food utilization...

Professor Laurence Hurst, of the University of Bath, said: "Key to the new understanding is the realization that the amount of energy organisms squeeze out of their food depends on how much food they have. Give them abundant food and they use it inefficiently. When we combine this with the notion that organisms with different food-utilizing strategies are also affected in different ways by genetic mutations, then we discover a new principle, one in which both the fit and the unfit coexist indefinitely."

Dr Ivana Gudelj, also from the University of Exeter, said: "The fit use food well but they aren't resilient to mutations, whereas the less efficient, unfit consumers are maintained by their resilience to mutation. If there's a low mutation rate, survival of the fittest rules, but if not, lots of diversity can be maintained.

I wonder how this relates to human food consumption and efficiency. Do humans who are fit become more exposed to genetic mutations? It doesn't make sense in my brain at all. And what is their definition of "fit"?

[Blackcatbone]

You can't really compare human with bacterial reproduction. Bacteria reproduce by cell division and humans sexually. Sexual reproduction is actually a defense against bacteria that reproduce by dividing. This gives the sexual reproducers the advantage of having more genetic material to draw on, whereas bacteria need to run through many more generations to compete with us. It's an arms race. And mutations are an advantage, up to a point. Some are particularly harmful but the vast majority are not.

[Stabby]

Er, yeah, I'm a bit confused here. What Darwin meant by fitness was the ability to survive and reproduce. What we generally mean these days by fitness is actually the fitness of genes in building organisms that are good at propagating those genes. What these scientists are calling fitness is simply efficiency in metabolizing food. So we have bacteria who metabolize less food more efficiently and ones who metabolize more food less efficiently. Apparently both of these are decent strategies for survival of genes throughout generations. But by the modern definition of fitness both of these bacterial strategies are both fit because they sustain genes throughout generations. Within the little lab niche they have going on both strategies can thrive, for reasons I don't know but they obviously do. It would seem that less food, more efficiency, but less resilience to poor reproduction is just as good as the alternative at propagating those genes on to the next generation and the subsequent generations.


I am inclined to say that these people don't know how evolution works. Both strategies are fit. The fittest always propagate most prolifically, but fitness isn't so black and white. What they call fitness and unfitness are arbitrary and not what the word actually means.

If a man happens to have the tendency of sleep with as many women as possible, and he gets 2 pregnant in his life, it is equally good an evolutionary strategy as a man who decided to marry his first girlfriend and have 2 children with her. Different strategies, same effect.

[Blackcatbone]

Oh, and I'll add that they're defining fit by their ability to efficiently use the energy from food. If you want a mammalian correlation it would actually be more like someone or something so specialized that when there's no longer any need for their particular talent or skill they can't survive. But if there's a high demand for that skill then the fittest will dominate. If there is more food than can be eaten then there's no need to be particularly efficient.