Why Was Sexual Reproduction Selected?

[Skidoo]

How could sexual reproduction be "invented" by a selection process?

Does anyone have a nice descriptive narrative?

[Propertarian]

I also wouldn't rule out pure randomness; since natural selection is random mutation + fitness selection, a mutation that is close to neutral in overall value fitness wise can stick and spread.

[chezlaw]

[ QUOTE ]
How could sexual reproduction be "invented" by a selection process?

Does anyone have a nice descriptive narrative?

[/ QUOTE ]
how about it it being discovered by a randomized searching process.

chez

[Xhad]

[ QUOTE ]
How could sexual reproduction be "invented" by a selection process?

Does anyone have a nice descriptive narrative?

[/ QUOTE ]

Start four paragraphs down or so

Single-celled organisms that trade genetic material would be analogous to the discussion about "half-wings" and "half-eyes".

Wiki on bacterial conjugation

[Rduke55]

Lots of good answers in the thread on diversity, etc.

Sexual reproduction was a monstrous step in evolution.

Another thing to think about this is that sexual reproduction de-links traits from the genome. With sexual reproduction you can combine different traits from individual genomes. Now good and bad mutations can be separated so good traits from different lineages can be combined and bad traits removed.
If you reproduce asexually, the good and bad pretty much are always together, placing severe limitations on evolving. It's much harder to get rid of the bad mutations.

[Rduke55]

[ QUOTE ]
I also wouldn't rule out pure randomness; since natural selection is random mutation + fitness selection, a mutation that is close to neutral in overall value fitness wise can stick and spread.

[/ QUOTE ]

This seems to be a theme we keep coming back to.
This depends on population size. In small populations this is much more likely (and probably accounts for a good deal of speciation). In large populations it's pretty much selection.

[Skidoo]

Chezlaw and Xhad,

Thanks for the replies. I thought it would be useful to encourage a schematic discussion on the sexual differentiation of an asexual population through mutation and selection.

This could shine considerable light on the topic of the OP.

[Mickey Brausch]

[ QUOTE ]
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?

[/ QUOTE ]Dear hmkpoker,

Start with the premise that humans are a small part of mammals who are a small part of vertebrates who are a tiny, tiny part of the fauna extant on earth -- and that the "paradigm" of "two-sex, sperm/egg congress" is not really that frequent.

Homo Sapiens is at the extreme right tail of the distribution of Life, as prominent an example of cosmic variance as any. Human "paradigms" are not typical of the ways of Life on Earth at all.

Regards,

Mickey Brausch

[Rduke55]

[ QUOTE ]
Start with the premise that humans are a small part of mammals who are a small part of vertebrates who are a tiny, tiny part of the fauna extant on earth -- and that the "paradigm" of "two-sex, sperm/egg congress" is not really that frequent.

[/ QUOTE ]

Um, in fauna it is.

[Mickey Brausch]

[ QUOTE ]
[ QUOTE ]
Start with the premise that humans are a small part of mammals who are a small part of vertebrates who are a tiny, tiny part of the fauna extant on earth -- and that the "paradigm" of "two-sex, sperm/egg congress" is not really that frequent.

[/ QUOTE ]

Um, in fauna it is.

[/ QUOTE ]Um, I ommited several steps to make my point. Tried to save space.

Cellular organisms; Eukaryota; Fungi/Metazoa group; Metazoa; Eumetazoa; Bilateria; Coelomata; Deuterostomia; Chordata; Craniata; Vertebrata; Gnathostomata; Teleostomi; Euteleostomi; Sarcopterygii; Tetrapoda; Amniota; Mammalia; Theria; Eutheria; Euarchontoglires; Primates; Haplorrhini; Simiiformes; Catarrhini; Hominoidea; Hominidae; Homo Sapiens; Sklanskyata.

Mickey Brausch