Why Was Sexual Reproduction Selected?

[hmkpoker]

Here's something I don't understand about natural selection: why was the two-sex, sperm/egg congress paradigm selected? Many species have the ability to reproduce asexually, and I would think that that's more advantageous to survival as it's simpler. Can anyone shed some light on this?

[GBP04]

I think it has something to do with the genetic variety sexual reproduction allows (compared with the rather limiting method of asexual cloning). More variety = greater chance of success.

[Sephus]

seems like it facilitates diversity.

[Girchuck]

Sexual reporduction provides better protection against parasites.

[thylacine]

Also bacteria sometimes "do it" by exchanging DNA.

[Propertarian]

The old explanation was that sexual reproduction promotes diversity.

Two modern explanations:

A) Kondrashov's: Most mutations are harmful, and sexual reproduction limits the propogation of harmful mutations.

B) The theory with the most support is a more nuanced version of the old view: sexual reproduction leads the organism to be better able to fight disease/parasite, because it can retain genes that aren't useful now but have potential. This is called the "Red Queen Hypothesis" and the explanation for why retaining genes that have potential is so important for fighting disease is somewhat long, but you probably can sucessfully google it.

Asexuality is more common in species that have avoided diseases/are little harmed by them.

[GBP04]

[ QUOTE ]
The old explanation was that sexual reproduction promotes diversity.

Two modern explanations:

A) Kondrashov's: Most mutations are harmful, and sexual reproduction limits the propogation of harmful mutations.

B) The theory with the most support is a more nuanced version of the old view: sexual reproduction leads the organism to be better able to fight disease/parasite, because it can retain genes that aren't useful now but have potential. This is called the "Red Queen Hypothesis" and the explanation for why retaining genes that have potential is so important for fighting disease is somewhat long, but you probably can sucessfully google it.

Asexuality is more common in species that have avoided diseases/are little harmed by them.

[/ QUOTE ]

Those are both valid points, but to disregard the former (which, I don't think you are doing) is silly.

[hmkpoker]

These are interesting points. This probably explains where recessive genes come into play.

[FortunaMaximus]

Sheer entertainment value? Sex is fun. And the mistakes keep the process interesting.

Is it the most efficient form of exponential growth? Probably not. <shrugs>

[suppasonic]

This may not explain fish or lizards, but for mammals, with two parents raising a newborn it would suggest a lower infant mortality rate...