evolutionary reasons for sex

For discussion of issues pertaining to sexuality. Warning: Topics within this forum may contain frank discussion of a sexual nature.
michaels
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evolutionary reasons for sex

Postby michaels » Mon Jul 18, 2011 7:01 pm

A recent article discusses why sexual reproduction exists, and mentions research showing that sexual reproduction (as opposed to asexual reproduction) increases long-term resistance to parasites:

http://www.livescience.com/15096-sex.html

What I love about this is the fact that only _genetically unusual_ pairings produce offspring with evolutionary advantages in terms of parasite resistance. Something like this has been seen in the case of blond people. The very first blond person is thought to have been born about 20,000 years ago, but blond people now make up 20% of the world's population. I'm not saying that blonde hair confers an advantage, but genes often occur in groups, and some other gene associated with blondness does confer an advantage.

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tysephine
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Re: evolutionary reasons for sex

Postby tysephine » Sun Jul 24, 2011 7:02 pm

It would make sense that the constantly intermixing genes would promote evolution, kind of like puting things together until the right combination is made. Asexual reproduction would produce the same genes over and over, not allowing for adaptation. Don't adapt--dead.

I don't plan on reproducing, so my parasites are probably happy. :)
"If it looks like a duck, and quacks like a duck, we have at least to consider the possibility that we have a small aquatic bird of the family anatidae on our hands." -Douglas Adams

michaels
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Re: evolutionary reasons for sex

Postby michaels » Tue Jul 26, 2011 4:11 am

tysephine wrote:I don't plan on reproducing, so my parasites are probably happy. :)


:) Mine too.

Interestingly, I came across another article where some researchers state that sexual reproduction promotes species _stability_ by making sure offspring are as similar as possible to the parents, while it is asexual reproduction that actually promotes diversity within a species. I can dig out the link if people want to read it.

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tysephine
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Re: evolutionary reasons for sex

Postby tysephine » Fri Jul 29, 2011 7:44 am

That's interesting, but you would think logically that it would be the other way around--that multiple combinations of dominant and recessive genes would produce the most diverse genetic makeup and that the asexual reproduction would constantly produce the same organism. That would be why some people are born with traits that had been recessive in both parents.

And yet...we evolved out of one-celled organisms once, or so the theory goes, right? Hmm.

But then I have only had one class that covered evolution, and that was college Physical Anthropology. Most teachers in the schools I have been to in Alabama (which is admittedly few) skip the chapter on evolution, for whatever reason. [An interesting aside--Alabama science textbooks have a sticker inside the front cover that disclaims any information within so that parents can't complain about the "questionable" contents, like evolution, etc. Do other states do that?]
"If it looks like a duck, and quacks like a duck, we have at least to consider the possibility that we have a small aquatic bird of the family anatidae on our hands." -Douglas Adams

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Dargon
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Re: evolutionary reasons for sex

Postby Dargon » Fri Jul 29, 2011 4:38 pm

tysephine wrote:[An interesting aside--Alabama science textbooks have a sticker inside the front cover that disclaims any information within so that parents can't complain about the "questionable" contents, like evolution, etc. Do other states do that?]


Product of the Texas public education system here. Our textbooks do not have such a sticker, but our (newly defeated) education standard was a "strengths and weaknesses" approach, which taught a straw-man version of evolution as well as several soundly refuted "weaknesses" of the theory.

That being said, it seems to me that sexual reproduction would lead to higher diversity within the species, as well as taking less generations for trait selection than asexual reproduction. With asexual reproduction, the only changes are mutations when budding off; favorable and the new strain may overrun the old; unfavorable and it will likely die off; no effect and it will probably coexist. With sexual reproduction, different sets of traits, as well as mutations, will pass to the individual offspring, leading to greater change per generation. This seems it would allow more competition between those different organisms within the same generation, weeding out unfavorable traits and propagating favorable traits in fewer generations.

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Re: evolutionary reasons for sex

Postby michaels » Sat Jul 30, 2011 6:27 pm

Just as an aside, the creationism battle had been won in the 19th century until the United States decided to backslide itself back into the 17th. I'm saddened by the thought of millions of schoolkids in the world's most powerful country being "educated" to believe that the world was created 6,000 years ago.

As for the main issue, what you both say makes lots of sense. I've tried to dig out the article but haven't been able to find it again.

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tysephine
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Re: evolutionary reasons for sex

Postby tysephine » Fri Aug 05, 2011 7:57 pm

Michaels, that's just the thing--we weren't taught creationism or evolution. We were taught nothing about how we came to be where we are now. At least here in Mobile, we were taught the basics of biology and very little else. There was basic instruction and the occasional dissection. Nothing near theorizing how humans were created/came to be as they are.

A little off topic, but I didn't want you guys thinking we were all religious nuts--just uninformed and a little afraid of the threat of a lawsuit from angry parents (one way or the other--the few liberal parents in AL would probably throw a FIT if creationism was taught while evolution was ignored. All 3 of them ;) ).
"If it looks like a duck, and quacks like a duck, we have at least to consider the possibility that we have a small aquatic bird of the family anatidae on our hands." -Douglas Adams

michaels
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Re: evolutionary reasons for sex

Postby michaels » Sat Aug 06, 2011 12:41 pm

I don't know what's worse, teaching only creationism/evolution or not teaching anything at all. The best approach to take would be to present both sides and make sure students understand the question is controversial. (I've talked to creationists who present some pretty impressive scientific-sounding (if pseudoscientific) arguments to support their cause, and I wouldn't be against kids being exposed to those arguments as long as there was balance.)

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Dargon
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Re: evolutionary reasons for sex

Postby Dargon » Sat Aug 06, 2011 4:33 pm

My problem with your statement, Michael, is that creationism is not science, and as such should stay out of the science classrooms. If you can present me with a scientific argument for creationism, I may change my mind, but all I have ever seen is poor and soundly debunked arguments against evolution (which are not arguments for creationism). Anything I have heard "for" creationism is nothing more than argument from ignorance.

I have no qualms with creationism being taught in a theology class, but not in science.

michaels
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Re: evolutionary reasons for sex

Postby michaels » Sun Aug 07, 2011 11:50 am

Dargon wrote:My problem with your statement, Michael, is that creationism is not science, and as such should stay out of the science classrooms. If you can present me with a scientific argument for creationism, I may change my mind, but all I have ever seen is poor and soundly debunked arguments against evolution (which are not arguments for creationism). Anything I have heard "for" creationism is nothing more than argument from ignorance.

I have no qualms with creationism being taught in a theology class, but not in science.


Those poor and soundly debunked arguments are popular and prevalent enough that they need to be presented in a science classroom as at least a widespread phenomenon. I'm not saying science teachers should argue in favor of creationism, just present creationists' arguments and the counterarguments from the scientific community.

But as long as sleepy-eyed government pencil-pushers are in charge of things and obsessed with avoiding confrontation, that won't happen, and kids will have to find things out for themselves.

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Dargon
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Re: evolutionary reasons for sex

Postby Dargon » Sun Aug 07, 2011 2:47 pm

I guess I misunderstood what you meant by presenting the arguments. I would be okay with using science to debunk the non-science commonly presented as counters to the theory of evolution.

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Re: evolutionary reasons for sex

Postby PiF » Tue Nov 29, 2011 12:24 am

if we didn't have sex where would all the people writing books about it come from?

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Re: evolutionary reasons for sex

Postby michaels » Tue Nov 29, 2011 10:28 pm

PiF wrote:if we didn't have sex where would all the people writing books about it come from?


And 85% of websites on the internet wouldn't exist.