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How and why did sexual reproduction evolve?

Jakeross6
Posts: 17
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10/13/2013 12:03:09 PM
Posted: 3 years ago
There are several hypotheses to explain the evolution of sex. While sex has many costs such as time, energy, the need to protect young, among others. However, it has the advantage of diversity of genomes and variation so that no one weakness is exploited and used against the species, like any asexual organism could have.

So under what circumstances would something like sex evolve in?
Such
Posts: 1,110
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10/13/2013 12:13:43 PM
Posted: 3 years ago
At 10/13/2013 12:03:09 PM, Jakeross6 wrote:
There are several hypotheses to explain the evolution of sex. While sex has many costs such as time, energy, the need to protect young, among others. However, it has the advantage of diversity of genomes and variation so that no one weakness is exploited and used against the species, like any asexual organism could have.

So under what circumstances would something like sex evolve in?

Circumstances that include competition, diversity, and adaptation.
Jakeross6
Posts: 17
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10/13/2013 12:17:05 PM
Posted: 3 years ago

Circumstances that include competition, diversity, and adaptation.

Obviously but the question is under what circumstances would it evolve. For instance, what made the shark evolve its claspers (or peni) for sexual purposes?
Lordknukle
Posts: 12,788
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10/13/2013 12:50:27 PM
Posted: 3 years ago
At 10/13/2013 12:17:05 PM, Jakeross6 wrote:

Circumstances that include competition, diversity, and adaptation.

Obviously but the question is under what circumstances would it evolve. For instance, what made the shark evolve its claspers (or peni) for sexual purposes?

There are several theories for the entire concept, but I doubt that anybody knows much about why specific species did so.
"Easy is the descent to Avernus, for the door to the Underworld lies upon both day and night. But to retrace your steps and return to the breezes above- that's the task, that's the toil."
Bullish
Posts: 3,527
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10/13/2013 1:05:33 PM
Posted: 3 years ago
This is just off the top of my memory, so I apologize for the lack of sources. I'm fairly sure it is at least possible if not essentially accurate.

Originally, there were only "females". These "females" reproduce by splitting. Over time, micro-organisms gained the ability to share DNA; many bacterial organisms today have the ability to absorb each other's DNAs and integrate them.

Eventually, the females started giving birth to abnormal packages of DNA, hence, the "male" version of the organism evolved. The males cannot reproduce, but are simply mutated versions of the females that specialize only in carrying DNA variation. At this point, the females are still fully capable of asexual reproduction, but can choose to integrate (have sex) with males; If I am not mistaken, certain types of aphids can do this today.

The males can be essentially thought of as highly complex and beneficial viruses to the females.

Then, purely sexual relationships developed as males started to become more dominant and asexual reproduction became obsolete.
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Jakeross6
Posts: 17
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10/13/2013 8:41:44 PM
Posted: 3 years ago
At 10/13/2013 1:05:33 PM, Bullish wrote:

...Then, purely sexual relationships developed as males started to become more dominant and asexual reproduction became obsolete.

One I have been looking into is called the Red Queen Hypothesis currently being studied at The University of Indiana. It is the idea that the original females evolved sex due to the risk of infection wiping out an asexual species. Infection meaning any sort of bad genetic mutation, weaknesses that can be exploited by predators and so on an so forth, that sex increased their fitness to survive and reproduce in their environments and be favored by the selective pressures of Natural Selection.

This hypothesis would say that the increased diversity while being costly would ultimately have more benefits than costs. It further states that rapid sexual reproduction could lead to the end of the species, which I question, as many insects reproduce at an astronomical rate. However, I haven't looked to far into it yet.

Below is a link to the University's page on the Hypothesis.

http://www.indiana.edu...

I really do find evolution fascinating along with any other aspect of biology, which is rooted in evolution. It is very fascinating.
Jack212
Posts: 572
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10/16/2013 5:31:05 PM
Posted: 3 years ago
At 10/13/2013 8:41:44 PM, Jakeross6 wrote:
At 10/13/2013 1:05:33 PM, Bullish wrote:

...Then, purely sexual relationships developed as males started to become more dominant and asexual reproduction became obsolete.


One I have been looking into is called the Red Queen Hypothesis currently being studied at The University of Indiana. It is the idea that the original females evolved sex due to the risk of infection wiping out an asexual species. Infection meaning any sort of bad genetic mutation, weaknesses that can be exploited by predators and so on an so forth, that sex increased their fitness to survive and reproduce in their environments and be favored by the selective pressures of Natural Selection.

This hypothesis would say that the increased diversity while being costly would ultimately have more benefits than costs. It further states that rapid sexual reproduction could lead to the end of the species, which I question, as many insects reproduce at an astronomical rate. However, I haven't looked to far into it yet.

Below is a link to the University's page on the Hypothesis.

http://www.indiana.edu...

I really do find evolution fascinating along with any other aspect of biology, which is rooted in evolution. It is very fascinating.

Insects also have a high mortality rate, so the two balance out. If humans reproduced that quickly or had that many offspring at a time, we'd all be dead within a week.
Jakeross6
Posts: 17
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10/16/2013 8:06:38 PM
Posted: 3 years ago
At 10/16/2013 5:31:05 PM, Jack212 wrote:
At 10/13/2013 8:41:44 PM, Jakeross6 wrote:
At 10/13/2013 1:05:33 PM, Bullish wrote:

...Then, purely sexual relationships developed as males started to become more dominant and asexual reproduction became obsolete.


One I have been looking into is called the Red Queen Hypothesis currently being studied at The University of Indiana. It is the idea that the original females evolved sex due to the risk of infection wiping out an asexual species. Infection meaning any sort of bad genetic mutation, weaknesses that can be exploited by predators and so on an so forth, that sex increased their fitness to survive and reproduce in their environments and be favored by the selective pressures of Natural Selection.

This hypothesis would say that the increased diversity while being costly would ultimately have more benefits than costs. It further states that rapid sexual reproduction could lead to the end of the species, which I question, as many insects reproduce at an astronomical rate. However, I haven't looked to far into it yet.

Below is a link to the University's page on the Hypothesis.

http://www.indiana.edu...

I really do find evolution fascinating along with any other aspect of biology, which is rooted in evolution. It is very fascinating.

Insects also have a high mortality rate, so the two balance out. If humans reproduced that quickly or had that many offspring at a time, we'd all be dead within a week.

Yes, I forgot about that. In the description, it says it goes against several hypotheses that are pretty well known. I watched a video on the "Evolution of sex" by the History channel, but it didn't provide more than a few animals that reproduce sexually.

http://personales.upv.es...

That on the other hand was a much better source.
johnlubba
Posts: 2,892
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10/17/2013 1:40:39 PM
Posted: 3 years ago
At 10/13/2013 1:05:33 PM, Bullish wrote:
This is just off the top of my memory, so I apologize for the lack of sources. I'm fairly sure it is at least possible if not essentially accurate.

Originally, there were only "females". These "females" reproduce by splitting. Over time, micro-organisms gained the ability to share DNA; many bacterial organisms today have the ability to absorb each other's DNAs and integrate them.

Eventually, the females started giving birth to abnormal packages of DNA, hence, the "male" version of the organism evolved. The males cannot reproduce, but are simply mutated versions of the females that specialize only in carrying DNA variation. At this point, the females are still fully capable of asexual reproduction, but can choose to integrate (have sex) with males; If I am not mistaken, certain types of aphids can do this today.

The males can be essentially thought of as highly complex and beneficial viruses to the females.

Then, purely sexual relationships developed as males started to become more dominant and asexual reproduction became obsolete.

That is quite a convincing explanation, but why did it happen to so many species.?
drafterman
Posts: 18,870
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10/17/2013 1:50:32 PM
Posted: 3 years ago
At 10/17/2013 1:40:39 PM, johnlubba wrote:
At 10/13/2013 1:05:33 PM, Bullish wrote:
This is just off the top of my memory, so I apologize for the lack of sources. I'm fairly sure it is at least possible if not essentially accurate.

Originally, there were only "females". These "females" reproduce by splitting. Over time, micro-organisms gained the ability to share DNA; many bacterial organisms today have the ability to absorb each other's DNAs and integrate them.

Eventually, the females started giving birth to abnormal packages of DNA, hence, the "male" version of the organism evolved. The males cannot reproduce, but are simply mutated versions of the females that specialize only in carrying DNA variation. At this point, the females are still fully capable of asexual reproduction, but can choose to integrate (have sex) with males; If I am not mistaken, certain types of aphids can do this today.

The males can be essentially thought of as highly complex and beneficial viruses to the females.

Then, purely sexual relationships developed as males started to become more dominant and asexual reproduction became obsolete.

That is quite a convincing explanation, but why did it happen to so many species.?

Who said it did? Most likely it happened to one and that one is the ancestor of all sexually reproducing species today.
Jakeross6
Posts: 17
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10/17/2013 1:56:28 PM
Posted: 3 years ago
At 10/17/2013 1:50:32 PM, drafterman wrote:
At 10/17/2013 1:40:39 PM, johnlubba wrote:
At 10/13/2013 1:05:33 PM, Bullish wrote:
This is just off the top of my memory, so I apologize for the lack of sources. I'm fairly sure it is at least possible if not essentially accurate.

Originally, there were only "females". These "females" reproduce by splitting. Over time, micro-organisms gained the ability to share DNA; many bacterial organisms today have the ability to absorb each other's DNAs and integrate them.

Eventually, the females started giving birth to abnormal packages of DNA, hence, the "male" version of the organism evolved. The males cannot reproduce, but are simply mutated versions of the females that specialize only in carrying DNA variation. At this point, the females are still fully capable of asexual reproduction, but can choose to integrate (have sex) with males; If I am not mistaken, certain types of aphids can do this today.

The males can be essentially thought of as highly complex and beneficial viruses to the females.

Then, purely sexual relationships developed as males started to become more dominant and asexual reproduction became obsolete.

That is quite a convincing explanation, but why did it happen to so many species.?

Who said it did? Most likely it happened to one and that one is the ancestor of all sexually reproducing species today.

It most likely isn't from one ancestor. This is probably a case of convergent evolution. The various forms and ways to have sex. It could be argued though that for larger life forms to evolve, sexual reproduction is a requirement, as the only remaining asexual species (to my knowledge) are single celled organisms.
drafterman
Posts: 18,870
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10/17/2013 2:09:30 PM
Posted: 3 years ago
At 10/17/2013 1:56:28 PM, Jakeross6 wrote:
At 10/17/2013 1:50:32 PM, drafterman wrote:
At 10/17/2013 1:40:39 PM, johnlubba wrote:
At 10/13/2013 1:05:33 PM, Bullish wrote:
This is just off the top of my memory, so I apologize for the lack of sources. I'm fairly sure it is at least possible if not essentially accurate.

Originally, there were only "females". These "females" reproduce by splitting. Over time, micro-organisms gained the ability to share DNA; many bacterial organisms today have the ability to absorb each other's DNAs and integrate them.

Eventually, the females started giving birth to abnormal packages of DNA, hence, the "male" version of the organism evolved. The males cannot reproduce, but are simply mutated versions of the females that specialize only in carrying DNA variation. At this point, the females are still fully capable of asexual reproduction, but can choose to integrate (have sex) with males; If I am not mistaken, certain types of aphids can do this today.

The males can be essentially thought of as highly complex and beneficial viruses to the females.

Then, purely sexual relationships developed as males started to become more dominant and asexual reproduction became obsolete.

That is quite a convincing explanation, but why did it happen to so many species.?

Who said it did? Most likely it happened to one and that one is the ancestor of all sexually reproducing species today.


It most likely isn't from one ancestor. This is probably a case of convergent evolution. The various forms and ways to have sex. It could be argued though that for larger life forms to evolve, sexual reproduction is a requirement, as the only remaining asexual species (to my knowledge) are single celled organisms.

Even so, it happened early on to a relatively small set of species. It's not like fish evolved sexual reproduction independently of amphibians or reptiles, etc.
Jakeross6
Posts: 17
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10/17/2013 2:12:53 PM
Posted: 3 years ago
At 10/17/2013 1:56:28 PM, Jakeross6 wrote:
At 10/17/2013 1:50:32 PM, drafterman wrote:
At 10/17/2013 1:40:39 PM, johnlubba wrote:
At 10/13/2013 1:05:33 PM, Bullish wrote:
This is just off the top of my memory, so I apologize for the lack of sources. I'm fairly sure it is at least possible if not essentially accurate.

Originally, there were only "females". These "females" reproduce by splitting. Over time, micro-organisms gained the ability to share DNA; many bacterial organisms today have the ability to absorb each other's DNAs and integrate them.

Eventually, the females started giving birth to abnormal packages of DNA, hence, the "male" version of the organism evolved. The males cannot reproduce, but are simply mutated versions of the females that specialize only in carrying DNA variation. At this point, the females are still fully capable of asexual reproduction, but can choose to integrate (have sex) with males; If I am not mistaken, certain types of aphids can do this today.

The males can be essentially thought of as highly complex and beneficial viruses to the females.

Then, purely sexual relationships developed as males started to become more dominant and asexual reproduction became obsolete.

That is quite a convincing explanation, but why did it happen to so many species.?

Who said it did? Most likely it happened to one and that one is the ancestor of all sexually reproducing species today.


It most likely isn't from one ancestor. This is probably a case of convergent evolution. The various forms and ways to have sex. It could be argued though that for larger life forms to evolve, sexual reproduction is a requirement, as the only remaining asexual species (to my knowledge) are single celled organisms.

If this were the case, you wouldn't see any larger, more complicated organisms using anything but sexual reproduction (unless a new, better form evolved). Single celled organisms usually produces asexually, even though diversity is achieved by sharing DNA