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Author Topic:   The Evolution of sex
beanhead
Inactive Member


Message 1 of 28 (52589)
08-28-2003 12:47 AM


I am by no means an Expert on plants so Help me out here
Recently I was studying Plants(I don't normaly do this) and I got to thinking about angiosperms and how the reproduce By Sexual means.
Correct me if I am wrong but wasn't our last Common ancestor asexual or thought to be? Did both Evolve independent from each other? It seems we must have shared a common ancestor.... to me it seems unlikely a very similar Mutation like that would happen again... But I guess it could happen though.. However aren't those plants thought to have evolved from gymnosperms which are asexual aren't they?
thanks in advance

Replies to this message:
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Mammuthus
Member (Idle past 4818 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 2 of 28 (52602)
08-28-2003 4:00 AM
Reply to: Message 1 by beanhead
08-28-2003 12:47 AM


Hi beanhead,
Are you asking about the evolution of sex per se or the evolution of sexual reproduction in plants specifically?

Here is a general theoretical paper

Otto SP. Related Articles, Links
The advantages of segregation and the evolution of sex.
Genetics. 2003 Jul;164(3):1099-118.

and here is one on plants

Holsinger KE. Related Articles, Links
Reproductive systems and evolution in vascular plants
Proc Natl Acad Sci U S A. 2000 Jun 20;97(13):7037-42.

cheers,
M


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bobanio 
Inactive Suspended Junior Member


Message 3 of 28 (281530)
01-25-2006 1:50 PM
Reply to: Message 2 by Mammuthus
08-28-2003 4:00 AM


live sex
spam and porn link deleted and member banned.

This message has been edited by AdminJar, 01-25-2006 12:55 PM


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mark24
Member (Idle past 3538 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 4 of 28 (281576)
01-25-2006 7:26 PM
Reply to: Message 1 by beanhead
08-28-2003 12:47 AM


beanhead,

Sexual reproduction evolved long before gymnosperms appeared. In other words, gymnosperms, like angiosperms are generally sexual.

Mark


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halucigenia
Inactive Member


Message 5 of 28 (281751)
01-26-2006 12:42 PM
Reply to: Message 1 by beanhead
08-28-2003 12:47 AM


Yes sex evolved long long ago
As mark24 said long before gymnosperms 'sexual' plants appeared, if this is what this thread is actually about. My favourite revelation in biology class was that pteridophytes and bryophytes (ferns and mosses) actually produce mobile, flagellate sperm that fertilizes an egg in their sexual reproduction, just like us animals.
So our shared common 'sexual' ancestor was indeed a long long time ago.

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Brad McFall
Member (Idle past 3376 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 6 of 28 (281810)
01-26-2006 6:09 PM
Reply to: Message 1 by beanhead
08-28-2003 12:47 AM


beyond X and Y representations
Now that is question!!

Is there some way to think about sex synthetically or is it purely a part of our analytic capability?

I hate it that EVC moves on before I can leisurely develop a topic so you will need to press me with some kind of extraordinary endurance but I will respond in a particular direction and to a particular end if pressed.

I am begging to think indeed that the traditional symbols 0+ and <-0 mean more than we think they do.
So, you can simply pursue some of the more conventional responses in the thread or see how I will try to show that sex is matter of difference of 1-Dimensionality purely. I will develop some kind of hypothesis about temperature dependent sex creation in turtles if you push this further else I will simply say that a figure I have displayed on EVC before:


Click to enlarge

goes some what to show that individually while not an atom sex might be combinations of atoms that reflect different kinds of 1-D relations with "male" being less symmetrical than female when not at rest (in the physics sense).

The neat thing about ferns' sex is that I think some graphs about the different gene frequencies in haploids vs. diploids might indicate via the 1-D affects actual phenotype differences(not charms) of the heart shaped form which water mediates fusion of the different kinds of gametes in these plants.

This message has been edited by Brad McFall, 01-26-2006 06:14 PM


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halucigenia
Inactive Member


Message 7 of 28 (281924)
01-27-2006 4:00 AM
Reply to: Message 6 by Brad McFall
01-26-2006 6:09 PM


Haploid and diploid phase phenotypes
quote:
see how I will try to show that sex is matter of difference of 1-Dimensionality purely
you are going to have to explain a lot just for me to decipher what you are even trying to get at here (as usual Brad). That may be off topic but we will see where this thread goes.

quote:
The neat thing about ferns' sex is that I think some graphs about the different gene frequencies in haploids vs. diploids might indicate via the 1-D affects actual phenotype differences(not charms) of the heart shaped form which water mediates fusion of the different kinds of gametes in these plants.
Is there a problem with haploid and diploid phases of an organism expressing different phenotypes? Another interesting topic I had not thought of this before.
I was just amazed when I learned that plants had sperm :eek:

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Brad McFall
Member (Idle past 3376 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 8 of 28 (281985)
01-27-2006 12:58 PM
Reply to: Message 7 by halucigenia
01-27-2006 4:00 AM


Re: Haploid and diploid phase phenotypes
Ok I will start with the plants before trying to see if sex is not merely analytic. The synthesis is much vaguer to me but I have thought about it.

The line of sexual demarcation that I intend to denote is found on page 57 of Evolution and the Genetics of Populations
http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=16&t=124&m=1#1
chapter 3(Systematic Change of Gene Frequency: Sinlge Loci)
there, anyone with eyes can see two different cross lines. If my view is NOT off topic then male "sperm" is litterally redisplayable from that graph COMING OUT of the upper left corner thanks to water flowing "down"(?that is the question) to the lower right corner with the condition being that unstable and stable changes ( in the difference of phases of diploid and haploid survivals) in the haploid phenotype are divided by the difference of unions of gametes over time.

Once I get the visualization over, I will move on to discuss how the correlation shadows of relative correlations remand sexual differences BOTH in the distance WITHIN this graph and between any two given gametes IF RANDOMLY breeding. Water aside from tending to go "down" would tend to give random sperm directions, so a Hardy Weinberg starting point will not be put off in the begining of the -
discussion.

The prothallium does justice to Darwin's notion of a "brancH" in any plurivocal sense.
http://gecko.gc.maricopa.edu/~lsola/NonFlwr/fern105.htm
As a preview read Weyl on symmetry or be prepared for me to refer to it.
http://www.pupress.princeton.edu/titles/865.html

I wouldnt be saying that it is a problem with expressing different "phenotypes" but that the correlation beween phenotype and geneotype seperate geometrically (sexually) INTO the actual fern diploid form irreversibly including charms of fern morphology.


Click to enlarge

Above is my first expression between the one dimensional kind of symmetry I have consistently represented as "+" here on EvC and meiosis and inbreeding. Interestingly I had implicated heat and electricity contra Darwin (see thread
www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=10&t=160&m=169#169 -->www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=10&t=160&m=169#169">http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=10&t=160&m=169#169
)and inbreeding vs meiosis. Since this representation (it is about a year old)I was able to collapse the horizontal presentation in this figure. More later.

This message has been edited by Brad McFall, 01-28-2006 09:04 AM


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Brad McFall
Member (Idle past 3376 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 9 of 28 (282123)
01-28-2006 8:51 AM
Reply to: Message 2 by Mammuthus
08-28-2003 4:00 AM


another "classical" source
The Principles of Heredity by LH Synder

This is a book my Grandfather used to teach (genetics, (I suppose)) with… in the 50s. Here is page 355-6:

quote:
The modern development of genetics with its discovery of sex chromosomes, sex-linked, sex-influenced, and sex-limited genes, and the phenomenon of genic balance, has made it a necessity to include problems of sex determination and sex differentiation in any adequate review of heredity. Two problems are involved. First, why does one individual or one part of an individual develop into a male, another individual or part of an individual into a female? Second, why are different characteristics associated with the two sexes?

In regard to the first problem that of sex determination, there have in the past been two prevailing theories. One theory, built around the discovery of sex chromosomes, stated that sex, was unalterably determined by some internal chromosomal mechanism. The other theory, built around the demonstrated possibility of “sex reversal,” stated that sex was determined by environmental factors such as food, light, metabolic rate, and others. Today we know that neither of these alone is adequate to answer the question of ex determination. As is so often the case in science, a merging of the valid essentials of two or more hypotheses has furnished a nearer approach to the truth.


For me which parts make up which individuals all depend on how the perpendicular is “mentally” dropped (see thumbnails in
http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=16&t=124&m=1#1
).


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mark24
Member (Idle past 3538 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 10 of 28 (282253)
01-28-2006 7:56 PM
Reply to: Message 7 by halucigenia
01-27-2006 4:00 AM


Re: Haploid and diploid phase phenotypes
hal,

you are going to have to explain a lot just for me to decipher what you are even trying to get at here

Remember to breathe.

Remember.

Mark

This message has been edited by mark24, 01-28-2006 08:07 PM


There are 10 kinds of people in this world; those that understand binary, & those that don't

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halucigenia
Inactive Member


Message 11 of 28 (282339)
01-29-2006 3:42 PM
Reply to: Message 10 by mark24
01-28-2006 7:56 PM


Re: Haploid and diploid phase phenotypes
Is that a comment about punctuation, or am I not to hold my breath for an explanation?
I do, eventually, want to understand just one of Brad's posts :confused:

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halucigenia
Inactive Member


Message 12 of 28 (282345)
01-29-2006 4:39 PM
Reply to: Message 8 by Brad McFall
01-27-2006 12:58 PM


Re: Haploid and diploid phase phenotypes
I have had some time to think about this Brad, and now I think that I understand, please tell me if I am anywhere close to your way of thinking.

The multicellular haploid adult form of the fern is a graph/set of the multicellular diploid adult form in the way that a mandlebrot set is a graph/set of the julia sets that it contains?
If you could graph the 1-D symmetry (fractal dimension) of the prothallus as a complex plane, then the distance between any two given gametes, wether on the same prothallus or not, would indicate the symmetry of the resulting multicellular diploid adult form?

I like fractals, and have had some success in generating fern-like and cell-like fractals using iterative algorithms. I have always thought that cellular development could be explained by fractal geometry. ;)


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Brad McFall
Member (Idle past 3376 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 13 of 28 (282353)
01-29-2006 5:25 PM
Reply to: Message 12 by halucigenia
01-29-2006 4:39 PM


Re: Haploid and diploid phase phenotypes
I think it is justthat the diploid form just IS the haploid form differentially sexualized.This is a little hard to explain unless I start to dissect the sexs down to the largest atom aggregates they might be explained in. This would be the synthetic part whereas so far I only was trying to say something that does not remand any changes in knowledge. I might be wrong on the visualization as this depends somewhat on fern speciation but using the complex plane to situate my lexicology does not detract from my projection and pinpoints the relations I intended.

This message has been edited by Brad McFall, 01-29-2006 05:26 PM


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halucigenia
Inactive Member


Message 14 of 28 (282385)
01-29-2006 8:34 PM
Reply to: Message 13 by Brad McFall
01-29-2006 5:25 PM


Re: Haploid and diploid phase phenotypes
If the the haploid form IS just the diploid form differentially sexualized then the differentialisation is only sexual in the fact that the gametes are formalised as the water flow descends across the prothallus thus dimentionalising haploid form. If the MOTILE sperm tend to give non random directions, does this not invalidate the starting point and therefore disrupt the non deterministic outome of the chaiotic attractor of the complex plane? ;) ;) ;)

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macaroniandcheese 
Suspended Member (Idle past 2271 days)
Posts: 4258
Joined: 05-24-2004


Message 15 of 28 (282388)
01-29-2006 8:47 PM
Reply to: Message 14 by halucigenia
01-29-2006 8:34 PM


Re: Haploid and diploid phase phenotypes
i'm sure this belongs somewhere else in the discussion. but just how are our haploid reproductive cells different than the haploid phase of moss etc? and thus wouldn't that make them the important phase and us just carriers or something?

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