Evolution of Sex

[Jeff Corey]

...It is syzygy (a rather absurd word, really, I wonder what its origin is)...

It's from Greek suzugia meaning union, coupling, yoke of animals

 

[Dagny]

Dagny,

I had forgotten the cost of sex and attracting mates. I had never heard of the cost of males. Interesting.

I would think that STDs would not become prevalent until sexual reproduction had gone on for a while. By this time, the sexual organisms would be much fitter.

Co-adapted genes are important but it depends on their prevalence. If they are universal, it would not matter. I would think that natural selection would cause them to re-accumulate even if they are only in part of the population. I guess it depends on the frequency, the extra fitness and the dominant/recessive nature of the gene.

If it is successful, it will work but without sexual reproduction it is more difficult to become successful. Mutation takes much longer than sexual reproduction. If the cost of sexual reproduction are low enough that it can get started, I would think it would spread. But with the costs you mention, sexual reproduction might be too expensive for a poorly adapted organism to survive.

Thanks for the info about the cost of reproduction. I have read a fair amount about genetics and it is great to learn more.

CBL

I was never terribly impressed with the cost STDs either but it is something to add in with all the other costs, really.
I agree that co-adapted genes would probably re-accumulate, but if breaking them up means the offspring don't survive at all, then the recombination is happening just in the species as a whole, and not in a given genetic line.
I'm taking genetics right now (awesome), but we aren't even talking about these things. 

 

[CBL4]

I'm taking genetics right now (awesome), but we aren't even talking about these things

Unfortunately, I stopped after 2 semesters of biology in college and never took genetics. I first read "The Selfish Gene" as a junior. If I had read it earlier, I probably would have taken genetics. I am self educated via popular science books and I find it fascinating.

If I had the chance to do it again, I might have gone into genetic research. I do not like the messy stuff of biology but I love the mathematical part of genetics.

CBL

 

[Dagny]

CBL4,

I was self-educated for a long time that way too (through high school and the first two years of college which were easy, and therefore boring! ;P). Dawkins is really one of the best pop science authors out there. In fact, aside from maybe Carl Sagan, the only one I still like. Personally, I've always had it bad for game theory because of "The Selfish Gene" but I'm not as strong on the math as I'd like to be.
You should pick up some text books on genetics. It sounds geeky, but that's what I did for behavior, and it's totally worth it.

 

[RandFan]

I don't have much to add to Hans' description but I thought I'd add a little something that I find absolutely fascinating.

It appears that some Aphids actually produce genetic clones of themselves. It's only ever females and they can produce varying body types, despite being genetically identical. Why they do this I'm not sure but it would appear that this happens when there is no male around to reproduce with. As an evolutionary trait this would seem to make sense as you get another chance to pass on your genes if partners are in short supply, you just pop out a few clones to take over after you expire.

Yes I know it's not strictly speaking on topic but, I thought you might find it interesting.

Kaydens.

No, it's excellent. I think this kind of periphery information is very relevant. It shows the extent of evolutionary response to reproduction. My thanks to Hans and anyone else who contributed. I was formulating a similar question. This goes hand in hand with an earlier question I had about the rise of diversity since it seemed to take diversity to achieve diversity I thought it was a paradox but others who were smarter than I helped me to understand the error of my ways.

Again, thanks to all who participated.

 

[Phaycops]

I apologize if someone's already said this; I didn't read the entire thread, as in the middle of reading, I suddenly found out that I have actual work to do! Yikes!

Anyway, the book the Red Queen by Matt Ridley covers the evolution of sex. Quite a good read, as well. Share and Enjoy.

 

[CBL4]

Dagny,

I agree that game theory and genetic is fascinating. My strengths are math and computers and I am frequently surprised by the lack of sophistication that geneticists show in these fields.

Are there any genetic textbooks you recommend? (Geeky is my middle name) I would be particularly interested in ones that are likely to be in a local library or used. Text books are ridiculously expensive.

Other than Dawkins, I recommend:
"Endless Forms Most Beautiful: The New Science of Evo Devo and the Making of the Animal Kingdom" by Sean B. Carroll.

I also read a really good book on the evolution of the immune system but I forget its title.

CBL

 

[Dagny]

Dagny,

I agree that game theory and genetic is fascinating. My strengths are math and computers and I am frequently surprised by the lack of sophistication that geneticists show in these fields.

Are there any genetic textbooks you recommend? (Geeky is my middle name) I would be particularly interested in ones that are likely to be in a local library or used. Text books are ridiculously expensive.

Other than Dawkins, I recommend:
"Endless Forms Most Beautiful: The New Science of Evo Devo and the Making of the Animal Kingdom" by Sean B. Carroll.

I also read a really good book on the evolution of the immune system but I forget its title.

CBL

You know, in general I'm surprised that so many fields are so incestual, and fail to utilize all the different techniques and knowledge that's around. I'm sort of a paleo/geology geek on the sly, and it always kills me how little biology students know about the earths history/the fossil record etc. Especially when it comes to issues like global warming.
The text book for my class is "Genetics: from genes to genomes" By Hartwell, Hood, Goldberg and a bunch of other people. It's a second edition.
I don't have anything for comparision, but I think it's pretty clear as text books go. Lots of practice problems with each chapter. My teacher wrote the solutions manual (which is seperate, and very helpful). I'm sure the first edition would be just as informative. You ought to check out amazon, and other such sites; word on the street is they have textbooks for much lower prices than you'd expect to pay in a campus bookstore/college town. I wouldn't know, I always wait till the last minute and then complain about how I could have bought a boat.

 

[Dagny]

By the way, didn't you know geeky is "cool" now?

Anecdotal evidence: rich, anorexic, bleached blonde girls wear shirts that read "I heart geeks". It's pretty obvious they don't.

 

[BillHoyt]

By the way, didn't you know geeky is "cool" now?

Anecdotal evidence: rich, anorexic, bleached blonde girls wear shirts that read "I heart geeks". It's pretty obvious they don't.

Huh? That explains all the strippers that keep hanging around me. I knew something was up. And here I was exercizing, buffing myself up, waxing off my body hair and rubbing myself down with body lotions. I'll have to exchange my contacts for plastic-rimmed glasses instead.

 

[neutrino_cannon]

I was wondering if anyone could provide any sites that detail the evolution of sex.

From A-Sexuality to Sexuality and detailing the between stages.

Also I wanted to know,Are there any fossils of animals that are in a between stage of sexuality? Asexual/Sexual? I know worms are animals and are Asexual.


How did our evolutionary tree evolve sexualy? Asexuality-Sexuality? Which were the first sexual organisms?

If I had to guess, I would bet that the plasmids some bacteria can exchange intraspecies (and even inter-species, freaky!) represent something like a sexual/asexual intermediate.