In my understanding, the word “evolution” implies change to a population over time. Not as in “no two individuals are ever the same” but as in “gene frequency changes over time”. Some genes become more common in the population, others less common. Some genes may die out. New ones may arise through mutation.
If all that ever happened was simple reshuffling, eventually the frequencies will stabilise at a point where every possible gene at an location has an approximately equal frequency. And evolution could be said to have stopped there.Of course the imperfectness of replication implies that mutations happen, and so this is theoretical. Populations will change genetically over time as new genes arise.
I guess I am one those “people who are wrong” in thinking that selective pressure is part of the definition of evolution. I would argue that random population variation over time is not the same as evolution. But that is largely a matter of semantics. And anyway, fairly recent (small) changes in humanity has been observed, that are undoubtedly aided by selection pressures, So even with the way I use the word “evolution”, humans undoubtedly still evolve.
What a Maroon, living up to the 'nymsays
Re the use of “human” as a modifier, you could also point out that “human civilization,” “human language,” and “human sexual response” don’t get legal rights. Also, you can’t make a sandwich from a bread machine.
Matthew Herronsays
“Their gametes are,” not “our gametes are”? Are you a lizard person?
Gordon Davissonsays
this video brings up something I’ve been vaguely curious about for a while: selection between sperm. There’s obviously a lot of opportunity for selection, but to what extent is the success of a particular sperm actually correlated with the particular alleles it carries? I thought sperm didn’t bother with transcription and translation (though this is apparently not entirely true), so a sperm’s mostly running on proteins (& ribozymes) left over from before it matured. How much transcription and translation happens in the haploid-but-immature stages of spermatogenesis?
Damn.
I think I understood that.
PZ, you have a mistake in your math around 8:22.
2^3000 is approximately 10^903, not 10^1204.
I am likely wrong about this. Still…
In my understanding, the word “evolution” implies change to a population over time. Not as in “no two individuals are ever the same” but as in “gene frequency changes over time”. Some genes become more common in the population, others less common. Some genes may die out. New ones may arise through mutation.
If all that ever happened was simple reshuffling, eventually the frequencies will stabilise at a point where every possible gene at an location has an approximately equal frequency. And evolution could be said to have stopped there.Of course the imperfectness of replication implies that mutations happen, and so this is theoretical. Populations will change genetically over time as new genes arise.
I guess I am one those “people who are wrong” in thinking that selective pressure is part of the definition of evolution. I would argue that random population variation over time is not the same as evolution. But that is largely a matter of semantics. And anyway, fairly recent (small) changes in humanity has been observed, that are undoubtedly aided by selection pressures, So even with the way I use the word “evolution”, humans undoubtedly still evolve.
Re the use of “human” as a modifier, you could also point out that “human civilization,” “human language,” and “human sexual response” don’t get legal rights. Also, you can’t make a sandwich from a bread machine.
“Their gametes are,” not “our gametes are”? Are you a lizard person?
this video brings up something I’ve been vaguely curious about for a while: selection between sperm. There’s obviously a lot of opportunity for selection, but to what extent is the success of a particular sperm actually correlated with the particular alleles it carries? I thought sperm didn’t bother with transcription and translation (though this is apparently not entirely true), so a sperm’s mostly running on proteins (& ribozymes) left over from before it matured. How much transcription and translation happens in the haploid-but-immature stages of spermatogenesis?
Oops, my comment about some transcription and translation occurring in mature sperm was supposed to link to https://www.sciencedaily.com/releases/2006/02/060214225237.htm