Why has evolution produced a 50:50 sex ratio?

83 replies

Gentlygently · 16/12/2018 18:09

I presume there is some evolutionary reason to why humans (all mammals?) have a 50:50 sex ratio. But what is it? As a species we could probably survive with much fewer men, in a co-operative society. But maybe a race with more men (hence physically stronger) would fight the female dominated race and win?

OP posts:

MrsTerryPratcett · 16/12/2018 18:15

Evolution, innit?

What benefits the species doesn't 'win' the evolutionary race. It's what benefits the individual. Selfish gene.

AutumnCrow · 16/12/2018 18:14

50% chance

Original poster

Gentlygently · 16/12/2018 18:14

Bike I think slightly more males are born, and then slightly more die early, and then women live longer, so at any given point it is slightly in favour of women. But I meant something more drastic than 51:49.

Autumn where in my post did I imply otherwise?

OP posts:

Squall · 16/12/2018 18:14

Normally 105:100 ratio female to male without femicide I believe.

AutumnCrow · 16/12/2018 18:13

At conception there is 50% channel of male or female chromosomes making up the resulting zygote / embryo.

That's what sexual reproduction is.

NotDavidTennant · 16/12/2018 18:13

It's generally true for most sexually-reproducing species due to something called Fisher's principle.

BikeRunSki · 16/12/2018 18:11

I always thought that there were more women. No idea where I got that - O level biology maybe - and I am happy to be told that I am wrong.

AutumnCrow · 16/12/2018 18:11

Male humans and female humans are different sexes, part of the same species.

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