3 ms·

I'm of the opinion it all goes back to the gametes. Lots vs few. If a creatures can be extremely reproductively successful it adds weight to the success side

I'm of the opinion it all goes back to the gametes. Lots vs few. If a creatures can be extremely reproductively successful it adds weight to the success side of the success/failure equation, which in turn encourages more extreme behavior. Big risks can pay off if there exists the potential for big rewards. This results in more variation and hence a flatter curve. Averaging the same as females but more male geniuses and more male idiots. Any category that centers more toward one end of the spectrum of possibility I'd expect to see more males. Infant mortality, birth defects, high school dropouts, chess grandmasters, murderers, etc. The effect is not enormous but the further toward the extreme you go the more the measurement is going to be dominated by men.

SamReidHughes 5y ago
The problem with this explanation is that mammals have greater male variability, and birds have greater female variability, and the obvious cause [1] is that it depends on which side has more redundancy in their sex chromosomes. https://onlinelibrary.wiley.com/cms/asset/32d94fa6-e5a8-4c82-a35b-3ff327c0cf58/evo12224-fig-0002-m.jpg https://onlinelibrary.wiley.com/cms/asset/32d94fa6-e5a8-4c82... [1] Well, I have to say, it was obvious to me, back in middle school, though I didn't know about the mechanics of X chromosome mosaicism at the time. It'd have been pretty weird if none of the information used to construct the brain was on the X chromosome.
- causality0 5y ago
  Interesting. I wonder how that's influenced by the fact birds have specific reproductive seasons and 90% of bird species only take a single mate per season. A male bird doesn't really have the possibility of being hundreds of times as reproductively successful as another male bird.
  - SamReidHughes 5y ago
    Well, the evolutionary split on that difference is a long time ago, so the causality could only be in the opposite direction. It'd be pretty neat if there was a large relationship between sex chromosome size and species' mating patterns.

SamReidHughes 5y ago

The problem with this explanation is that mammals have greater male variability, and birds have greater female variability, and the obvious cause [1] is that it depends on which side has more redundancy in their sex chromosomes. https://onlinelibrary.wiley.com/cms/asset/32d94fa6-e5a8-4c82-a35b-3ff327c0cf58/evo12224-fig-0002-m.jpg https://onlinelibrary.wiley.com/cms/asset/32d94fa6-e5a8-4c82... [1] Well, I have to say, it was obvious to me, back in middle school, though I didn't know about the mechanics of X chromosome mosaicism at the time. It'd have been pretty weird if none of the information used to construct the brain was on the X chromosome.

causality0 5y ago
Interesting. I wonder how that's influenced by the fact birds have specific reproductive seasons and 90% of bird species only take a single mate per season. A male bird doesn't really have the possibility of being hundreds of times as reproductively successful as another male bird.
- SamReidHughes 5y ago
  Well, the evolutionary split on that difference is a long time ago, so the causality could only be in the opposite direction. It'd be pretty neat if there was a large relationship between sex chromosome size and species' mating patterns.