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RE: God, Darwin, and Kansas - 8/14/2006 12:38:45 AM   
seeksfemslave


Posts: 4011
Joined: 6/16/2006
Status: offline 		Lets look at this argument of Punctuated Equilibrium the truth of which is presented HERE as being without any doubt. In fact if you read the Wikipedia reference provided by anthrosub one of the first things you will find there is that it is the subject of much controversy between Paleontologists and Evolutionary Biologists.

If we consider the large mammalian explosion then it is accepted that a large number of new species appeared in short time scales. Quoting Punc. Eq....Due to a dilution effect in the main population this can only have come about by subgroups zooming off to all points of the compass, becoming isolated for some reason and then the latent potential for change has a chance to establish itself. A likely story ! We all know that many species that have behavioural volition, ie can make choices for themselves, are a vicious lot and would almost certainly kill or at the very least abandon any offspring showing any deviation from a norm. See the treatment handed out by birds, cant recall which species, if a chick becomes isolated from its parents. And these are the same species!!! Likewise with seals or walruses. Not sure which. Probably both! How then did the devient offspring develop and even if they did  develop it would be into variants of the parents. see the finches on the Galapogos.
My speculations entirely but they satisfy me.

With regard to daddys point claiming that  evolution has been observed in real time; it would have been such sensational news that even I would have heard about. That raises a point about...is it the dog that doesn't bark ? anthrosub says that new species of flies would not have evolved during genetic investigations because the environment remains the same. Surely some enterprising Natural Selectioner would have taken the opportunity to settle things once and for  all by experimenting with these little flies. Hasn't happened though has it ? Is that the silent dog ? Has been tried and just doesnt produce the required outcome.

Most of daddys other points I admit might be a trifle inconvenient for those who believe that all life originated at the same time.

With regard to DNA continuity thu' time, well life as we know it is DNA based, so daddy just notes that fact.

(in reply to Rule)
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RE: God, Darwin, and Kansas - 8/14/2006 2:33:13 AM   
Rule


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quote:

ORIGINAL: seeksfemslave

Lets look at this argument of Punctuated Equilibrium the truth of which is presented HERE as being without any doubt. In fact if you read the Wikipedia reference provided by anthrosub one of the first things you will find there is that it is the subject of much controversy between Paleontologists and Evolutionary Biologists.

I had prepared an exhaustive reply to your post, but it was lost due to CM time out.
So here a very short reply to this first part of your post:
I do not find any mention of such controversy in the Wikipedia article. Instead it says on line four of the first chapter 'PE's History' that the article by Eldridge and Gould caused Eldridge's theory of evolution by punctuated equilibria to be accepted by both palaeontologists and evolutionists.

(in reply to seeksfemslave)
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RE: God, Darwin, and Kansas - 8/14/2006 2:35:00 AM   
seeksfemslave


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Joined: 6/16/2006
Status: offline 		A couple more points.
Regarding the origin of DNA . N_ssers claim that the building blocks ie amino acids came into existence when the primordial soup was bombarded by high levels of Radiant Energy. But N_essers that bombardment just didnt stop and start to conveniently produce amino acids it was continuous and just as likely to have broken down any nascent acids. NO ?

Evolution of complex organs like wings or eyes.
Again N_essers these organs took a long time involving sequential steps to develop, during which time they were no bloodie use at all. Surely Natural Selection would have eliminated them. NO?

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RE: God, Darwin, and Kansas - 8/14/2006 2:43:23 AM   
meatcleaver


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Status: offline 		The development of eyes can be traced from simple photo sensitive cells in the skin. The whole sequential process can be mapped together from different species and all exist today so they are there to be studied and all have their uses by each species. All are of use.

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RE: God, Darwin, and Kansas - 8/14/2006 3:09:01 AM   
Rule


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quote:

ORIGINAL: seeksfemslave

A couple more points.
Regarding the origin of DNA . N_ssers claim that the building blocks ie amino acids came into existence when the primordial soup was bombarded by high levels of Radiant Energy. But N_essers that bombardment just didnt stop and start to conveniently produce amino acids it was continuous and just as likely to have broken down any nascent acids. NO ?
DNA does not consist of amino acids.
However that may be, of course there will be a loss of amino acids for whatever reasons. The point is that more will be made than are broken down, as was established in the experiment.
Anyway, they may also have been produced by other means.

quote:

ORIGINAL: seeksfemslave
Evolution of complex organs like wings or eyes.
Again N_essers these organs took a long time involving sequential steps to develop, during which time they were no bloodie use at all. Surely Natural Selection would have eliminated them. NO?

No, because even partial eyes are better than no eyes at all - except when they are useless, hence the blind cave fishes.
Also, organs may evolve for one purpose and subsequently being applied and evolve to another purpose entirely.
 

< Message edited by Rule -- 8/14/2006 3:10:01 AM >

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RE: God, Darwin, and Kansas - 8/14/2006 4:43:04 AM   
seeksfemslave


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Status: offline 		I am going to enlist Occam's Razor now.
I hope N_ssers would agree that two sex reproduction is more complex, and more expensive, than same sex reproduction. Therefore why did Natural Selection include the more complex path ?

Also again until the mechanism was "up and running" so to speak it conferred no advantage at all. Did it ? Even assuming it confers any advantage anyway !!

There are also examples in Nature where two at least "things" only perform a given function when both are present. Say A and B . A does nothing without B and vice versa. Without the target function being forseen how did such things come about.
Dont forget N_ssers we are talking complex molecules that add no advantage until both evolve. Wish I could be more specific but I believe Enzymes are involved here.

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RE: God, Darwin, and Kansas - 8/14/2006 4:45:08 AM   
philosophy


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Status: offline 		"I am going to enlist Occam's Razor now."

*blows whistle and calls a foul*

can't use logical tools on other people's arguments that you're not prepared to apply to your own.........

*shows yellow card*

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RE: God, Darwin, and Kansas - 8/14/2006 8:23:56 AM   
Rule


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quote:

ORIGINAL: seeksfemslave
If we consider the large mammalian explosion then it is accepted that a large number of new species appeared in short time scales. Quoting Punc. Eq....Due to a dilution effect in the main population this can only have come about by subgroups zooming off to all points of the compass, becoming isolated for some reason and then the latent potential for change has a chance to establish itself.

Where did you get the quote? It is not in the Wikipedia article, nor did I find it when I googled for it.
Anyhow, I studied the Wikipedia article and was shocked. What Darwin said makes more sense:
 
"I can by no means agree…that immigration and isolation are necessary elements. . . . Although isolation is of great importance in the production of new species, on the whole I am inclined to believe that largeness of area is still more important, especially for the production of species which shall prove capable of enduring for a long period, and of spreading widely." (1859:105-106)

"Throughout a great and open area, not only will there be a greater chance of favourable variations, arising from the large number of individuals of the same species there supported, but the conditions of life are much more complex from the large number of already existing species; and if some of these species become modified and improved, others will have to be improved in a corresponding degree, or they will be exterminated. Each new form, also, as soon as it has been improved, will be able to spread over the open and continuous area, and will thus come into competition with many other forms ... the new forms produced on large areas, which have already been victorious over many competitors, will be those that will spread most widely, and will give rise to the greatest number of new varieties and species. They will thus play a more important role in the changing history of the organic world." (1859:107-108)

I disagree with Eldridge that the main population stabilizes the genotype. It is nonsense. The main population will accumulate new alleles in their gene pool, as I explained before. You ought to pay attention to what I say, seeks, and not be distracted by people like Eldridge and Gould. There is no dilution of the main population when ecological niches open up, but fragmentation of the gene pool. The evolving individuals are all over the place. When they evolve into a new ecological niche it soon becomes disadvantageous to mate with the mother population and vice versa. Consequently, natural selection and sexual selection especially will select for any mutation that increases the reproductive barrier between the two populations; this barrier will be erected at an exponential rate, eventually causing speciation.

So clearly my own theory describing radiative evolution is far superior to the punctuated equilibria of Eldridge and Gould. Henceforth my theory will be called 'Rule's radiative evolution'.

quote:

ORIGINAL: seeksfemslave
A likely story ! We all know that many species that have behavioural volition, ie can make choices for themselves, are a vicious lot and would almost certainly kill or at the very least abandon any offspring showing any deviation from a norm. See the treatment handed out by birds, cant recall which species, if a chick becomes isolated from its parents. And these are the same species!!! Likewise with seals or walruses. Not sure which. Probably both!

This is blatant nonsense, seeks. There are plenty of examples of progeny that differ dramatically from their parents that are not murdered by their parents. As an obvious example I refer you to albino individuals that occur among various species and that obviously have not been murdered by their parents. Also there are many species of animals, bacteria, fungi and plants that have no parental care at all. You do not seriously expect those parents who do not know their progeny to seek out their abnormal progeny and kill them, do you? (Least of all plants.)
 
You are here talking about what happens when offspring is accidentally separated from their parents and are not accepted by other parents. That is a completely different subject entirely. It is another example of your unsound methods of discussion.

quote:

ORIGINAL: seeksfemslave
My speculations entirely but they satisfy me.

I commiserate with you.

< Message edited by Rule -- 8/14/2006 8:35:17 AM >

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RE: God, Darwin, and Kansas - 8/14/2006 8:26:23 AM   
Dauric


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Status: offline 		... This is just getting stupid. I'm not one who normally rips on specific users, but i'll make an exception here.

seeksfemslave has repeatedly proven, and admitted to the fact, that despite his interest in disproving evolution he won't engage himself enough to completely read much less make the effort to understand the arguments on the other side of the debate.

                                      "Never argue with a fool, people might not know the difference."

Just let him have the last word here, his wanton ignorance is on display for all to see.

If I had two pennies for every two-bit opinion I have I wouldn't need...

... $0.02,

Dauric.

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RE: God, Darwin, and Kansas - 8/14/2006 9:53:47 AM   
seeksfemslave


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Status: offline 		Mr Rule I AM listening to you, but I notice that you ask for my attention to be directed to you and not Eldridge and Gould which reveals that you KNOW exactly where in the Wikepedia I got my ACCURATE paraphrase regarding Punctuated Equilibrium.

You also claim that all paleontologists accept the Natural Selection interpretion of the fossil record. Reading between the lines in the Wikepedia shows that this is NOT so. I refer to the bit that says that when the paleontologists were acquainted with the truth, as perceived by N_ssers naturally they saw the light. That probably only means some paleontologists. I also found reference to a book by I think David Smith, a paleontologist not coming from the Creationis/ IDesign camp, who claims that neo Darwinism is hindering the search to unlock the mysteries of  the origin of life.

Incidently Mr Rule do you have any comments on my suggested experiment using short life cycle species to settle the question of the truth or otherwise of theOrigin of the Species by Natural Selection. In particular why no results have been announced. Surely little me could not be the first to consider it ?

Reminds me of the experiment to detect Neutrinos in a mine somewhere in US. Hasn't produce anything like the expected results but that fact doesn't deter Cosmologists from invoking the existance of Neutrinos to help their case. 

< Message edited by seeksfemslave -- 8/14/2006 10:03:02 AM >

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RE: God, Darwin, and Kansas - 8/14/2006 12:44:07 PM   
Rule


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quote:

ORIGINAL: seeksfemslave

Mr Rule I AM listening to you, but I notice that you ask for my attention to be directed to you and not Eldridge and Gould which reveals that you KNOW exactly where in the Wikepedia I got my ACCURATE paraphrase regarding Punctuated Equilibrium.
I am sorry. I do not. Otherwise I would not have asked.

quote:

ORIGINAL: seeksfemslave
You also claim that all paleontologists accept the Natural Selection interpretion of the fossil record. Reading between the lines in the Wikepedia shows that this is NOT so. I refer to the bit that says that when the palaeontologists were acquainted with the truth, as perceived by N_ssers naturally they saw the light. That probably only means some palaeontologists.

There is before and after Eldridge, of course. After most of them saw the light. However that may be, you know that I disagree with Eldridge's model. Rule's model of radiative evolution is now - and has been for years - the best.
 
quote:

ORIGINAL: seeksfemslave
I also found reference to a book by I think David Smith, a paleontologist not coming from the Creationis/ IDesign camp, who claims that neo Darwinism is hindering the search to unlock the mysteries of  the origin of life.

He may very well be right, depending upon his unknown arguments.

quote:

ORIGINAL: seeksfemslave
Incidently Mr Rule do you have any comments on my suggested experiment using short life cycle species to settle the question of the truth or otherwise of theOrigin of the Species by Natural Selection. In particular why no results have been announced. Surely little me could not be the first to consider it ?
Indeed, I answered that question in post 242, where I offered this link:
 
http://bio.fsu.edu/~dhoule/Publications/HouleRowe2003.pdf

Apparently you could not be bothered to click on the link and to read at least the introduction of the article.

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RE: God, Darwin, and Kansas - 8/14/2006 3:15:49 PM   
anthrosub


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Status: offline 		The "offspring killed by their parents notion" was the last straw for me.  Apparently, seeksfemslave is looking at everything through the wrong end of the microscope in my opinion.  I'm not trying to be cruel here, it's just obvious that the debate is running on two, very different levels of understanding.  There's no longer any point to this discussion as it stands.
 
anthrosub

_____________________________

"It is easier to fool people than it is to convince them they have been fooled." - Mark Twain

"I am not young enough to know everything." - Oscar Wilde

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RE: God, Darwin, and Kansas - 8/14/2006 5:30:09 PM   
Daddy4UdderSlut


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quote:

ORIGINAL: seeksfemslave
With regard to daddys point claiming that  evolution has been observed in real time; it would have been such sensational news that even I would have heard about.

Yep, that's one explanation - I must be making it up because you're unaware of it.   Another is that for the educated world, evolution is not "sensational news".  It is widely known that microbial adaptation to antimicrobial drugs is the greatest challenge facing the treatment of infectious diseases.  You may be blissfully unaware of what the medical community and the drug industry have been concerned with for the past 40 years, but virtually anyone who reads would know this.

Again and again, you are not only wrong, but wrong by a country mile!

Lest you still insist that I've made up a fairytale about microbes genetically adapting in real time to evade treatments - and your evidence? You don't know about it!!!     Frankly seeks, without even knowing experimentally that this happens, anyone who took an introductory microbiology course can predict that this would happen.

I did a quick search on hiv drug resistance, and among the results, found this little section designed to educate the absolute neophyte with medicine on the topic of HIV drug resistance.  This occurs, by the way, not only in populations, but in the course of a single patient's treatment - the drugs that worked at the beginning, don't work anymore.  What's happening, seeks?  Is God talking to the virus particles? telling them the secret of evading the drugs?
http://www.thebody.com/monogram/rc/rt101_basics.html#4

There, they answer some basic patient questions:
What Is HIV Drug Resistance?
HIV drug resistance means that the virus can adapt, grow, and multiply in the presence of drugs. HIV is considered to be drug resistant when a drug or class of drugs is no longer effective against it.

What Causes Drug Resistance?
HIV replicates very rapidly and makes many mistakes (mutations) in the process. However, HIV doesn't have the ability to correct these mistakes. This results in mutant viruses that can be resistant to one or more of the drugs used in HIV therapy. These mutant viruses continue to make copies of themselves, further reducing the effectiveness of an individual's HIV therapy.

How Common Is Drug Resistance?
According to recent data, in three out of four people currently taking HIV drugs, treatment failure is linked to drug resistance. Additionally, one in four newly infected individuals is already resistant to at least one HIV drug.

Following treatment failure
When a person no longer benefits from his or her HIV therapy (treatment failure) and viral load is increasing, drug resistance testing can help determine which drug or combination of drugs is no longer effective. A treatment plan can then be developed that is more likely to slow HIV replication.

(in reply to seeksfemslave)
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RE: God, Darwin, and Kansas - 8/14/2006 6:00:06 PM   
Daddy4UdderSlut


Posts: 240
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Status: offline 		Another little source that is non-technical, is from Wikipedia.  It's so short, that I will reproduce it below.  Jeez, seeks, I wonder why this "sensational news" isn't being trumpeted on every media outlet?  Could it perhaps be because evolution was adequately described by Darwin more than 150 years ago?   Nahhh, that's too obvious!  It must be some kind of bizarre and farfetched explanation that you will provide in your next post!

See:
http://en.wikipedia.org/wiki/Virus_evolution

Virus evolution is a subfield of evolutionary biology that is specifically concerned with the evolution of viruses. Many viruses, in particular RNA viruses, have fairly high mutation rates (on the order of one point mutation or more per genome per round of replication in RNA viruses) and short generation times. As a consequence of the elevated mutation rate, combined with natural selection, many viruses can adapt to changes in their environment within months. Virus evolution is an important aspect of the epidemiology of viral diseases such as influenza, HIV, hepatitis, and many others. It also causes problems in the development of successful antiviral drugs, as resistant mutations often appear within weeks to months after the beginning of the treatment.
RNA viruses are also used as a model system to study evolution in the laboratory.
One of the main theoretical models to study virus evolution is the quasispecies model.

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RE: God, Darwin, and Kansas - 8/15/2006 2:38:49 AM   
seeksfemslave


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Status: offline 		Daddy if you keep posting in comprehensible English I may start to like you. Not a lot though.

The Wikipedia offers this, there is no generally accepted definition of species but presents one that is consistant with Daddy's desription of changes to bacteria, naturally enough this DEFINITION was proposed by an N_sser E Mayr probably to save  the bacon of Natural Selection. A laymen like me thinks this...if it walks like a duck, talks like a duck, looks like a duck then regardless of whether it can procreate with other ducks it is a duck.
*****it is not a new species of , of, err, just a sec, oh dear, err err  DUCK****

Wikipedea says most known species have been described according to their morphology  ie body type.See my duck argument.
Natural Selectioners need to throw some light on their BELIEF that say ants and elephants having a common ancestor.Then we will be getting somewhere!Subscribers to E Mayr's definition accept that they are different species on the grounds that they cannot reproduce with one another. What  an insight!
Only joking !

Note Rule has his own explanation of Punctuated Equilibrium. There must be at least two explanations then! My problem with this kind of thing ie speculation disguised as explanation ,is not the speculation per se but that with regard to Natural Selection wild speculation has transmogrified (wow) and is presented as hard fact.

I came across this in the Wikipedia...N_ssers have great difficulty in explaining how sexual reproduction evolved....Translation...they have not got the foggiest idea how sexual reproduction came about but under no circumstances will that give them pause for thought, unless they can construct even wilder speculations to support their theories. Does the name Ptolemy mean anything to you lot. Very clever he was, explained the motion of the planets in a very satisfactory  way based on some quite ingenious maths. Slight problem...he was wrong. The maths is totally against N_ssers.

< Message edited by seeksfemslave -- 8/15/2006 3:00:00 AM >

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RE: God, Darwin, and Kansas - 8/15/2006 4:06:52 AM   
Rule


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quote:

ORIGINAL: seeksfemslave
The Wikipedia offers this, there is no generally accepted definition of species but presents one that is consistant with Daddy's desription of changes to bacteria, naturally enough this DEFINITION was proposed by an N_sser E Mayr probably to save  the bacon of Natural Selection.
Ehm, what kind of definitions of species are there, seeks? If you do not know them all, and have studied them, you are simply parrotting someone else.

Species have been defined to distinguish between macroscopic interbreeding populations. The simple definition of species is that different species do not produce fertile progeny when they mate. All else is a refinement of this simple definition and those refinements are for experts to break their heads over, not for lay persons like yourself.
 
Myself, I use a somewhat looser definition of species. I do not exclude that very infrequently fertile offspring may result from an interspecies mating. Most biologists will disagree with me about my definition of species, but I will always agree with their definition of species. My definition only applies in very rare, special circumstances: the process of speciation. Again, these finer distinctions are not for lay persons to concern themselves with.
 
The definition of species being so extremely useful when distinguishing macroscopic interbreeding populations, it was extrapolated to microscopic populations.
Such extrapolation to especially bacteria has its own difficulties, but it satisfies microbiologists. Even before DNA-sequencing, microbiology already was a very advanced science and DNA-sequencing corrected a lot of mistakes concerning the taxonomy of bacterial species. It works for microbiologists and that is all that is required of any definition.

< Message edited by Rule -- 8/15/2006 4:18:12 AM >

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RE: God, Darwin, and Kansas - 8/15/2006 5:30:35 AM   
seeksfemslave


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Status: offline 		Rule asks....
Ehm, what kind of definitions of species are there, seeks? If you do not know them all, and have studied them, you are simply parrotting someone else.

Really Rule to accuse me of parroting others!  It is you orthodox N_ssers who are the parrots. Responding with assertion, reason, superstitious belief in unproven speculation being scientific fact, and of course abuse. Why even anthrosub gets uppity sometimes ! By the way anthrosub infanticide in Nature is not rare. Often by neglect. How about the Pandas ?

Whatever you may think of my posts you MUST agree that they show evidence of someone who has examined the issue and thought critically about it for himself. Leave it to the experts/superiors is the cry of the authoritarian throughout the ages.

Science has its share of charlatans you know. I alluded to this way way back when I stated that rocking the boat for N_ssers is now quite difficult due to their vested career interest. Also Daddy early on claimed that most if not all reputable science journals only publish articles supporting Natural Selection as an indicator  that NS must be true.
In fact many journals refuse point blank to consider any article offering alternative explanations or a critique of NS.
Thus bringing about a form of NS, dont you know lol

< Message edited by seeksfemslave -- 8/15/2006 5:38:44 AM >

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RE: God, Darwin, and Kansas - 8/15/2006 5:31:26 AM   
Daddy4UdderSlut


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quote:

Most biologists have concluded that the proponents of intelligent design display either ignorance or deliberate misrepresentation of evolutionary science.
  Hmmm, that wouldn't be Mr. seeks, would it?

For others who may be reading this and actually trying to learn something, here are a few online sources that are authoritative and informative, re this discussion:

Natural History Magazine: Informative exchanges between 3 knowledgeable ID proponents, and 3 scientists:
http://www.actionbioscience.org/evolution/nhmag.html

National Academy of Sciences: "Science and Creationism:
A View from the National Academy of Sciences", an online pamphlet to point out some of the evidence for evolution for the laymen.
http://darwin.nap.edu/books/0309064066/html

American Association for the Advancement of Science: Board Resolution on Intelligent Design Theory.
http://www.aaas.org/news/releases/2002/1106id2.shtml

< Message edited by Daddy4UdderSlut -- 8/15/2006 5:32:31 AM >

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RE: God, Darwin, and Kansas - 8/15/2006 5:43:56 AM   
LadyEllen


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Status: offline 		I dont know much about biology, but it seems to me that sexual reproduction would be explained on the evolutionary side by reference to how asexual reproduction occurs.

In asexual reproduction, the single celled organism grows until it is large enough to divide and produce two viable organisms. Perhaps sexual reproduction occured at the basic level by two single celled organisms combining to temporarily produce a two celled organism which could then amass the material required for a third far more quickly than in the asexual state? On separation, there would be an extra organism produced.

However, this would assume that sexual reproduction as described can result in more rapid or numerous production of offspring than the simple "two together = half the time required" approach. Sexual reproduction has to be far more efficient than asexual, to provide this advantage in numerical terms. eg
If we take T as the time required for a single cell to reproduce, then in 10T it would produce 10 offspring
In the same 10T, a combination of two single cells could produce 20 offspring. However, the same two cells could have produced this number individually in the T period posited.

Sexual reproduction has to be however only slightly more efficient in numerical terms for it to be advantageous. And if for example sexual reproduction was 4 times more efficient in producing offspring than asexual, then
in 10T, a single cell would produce 10 offspring
a two celled combination would produce 40 offspring - or twenty more than the single cells could have done individually. A definite advantage.

As for the genetic advantage of combining sexually two identical single celled organisms - this is where things get interesting for steady state approaches. If the two individuals are identical, then their sexual offspring must also be identical to the parents, and thus no genetic advantage exists. If however, the two individuals are slightly variable, then their combination must necessarily produce a third which is differentiated from its parents. This difference can be advantageous or disadvantageous or neutral in the environment. Disadvantaged offspring would tend to less successful compared to the neutrals who would live on as their parents did, whilst the advantaged would be more successful than the neutrals, as long as the environment remained constant. Change in environment might later render the previously neutral more advantaged and leave the formerly advantaged at disadvantage - natural selection.

The question remains though, as to how two single celled organisms which are identical, can acquire variations which by combination in their offspring result in advantage/disadvantage for those offspring. Perhaps in the earliest times, when life of this form first took shape, it did so in slightly different forms according to location - but yet forms which could sexually reproduce and have viable offspring. This would have to be two forms closer in nature than man and ape of course. This would result in differentiation from the first encounter.

Just some ideas
E



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RE: God, Darwin, and Kansas - 8/15/2006 6:27:16 AM   
Rule


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quote:

ORIGINAL: LadyEllen
I dont know much about biology, but it seems to me that sexual reproduction would be explained on the evolutionary side by reference to how asexual reproduction occurs.
That is a good idea.

quote:

ORIGINAL: LadyEllen
In asexual reproduction, the single celled organism grows until it is large enough to divide and produce two viable organisms. Perhaps sexual reproduction occurred at the basic level by two single celled organisms combining to temporarily produce a two celled organism

That also is a good idea. I have forgotten a lot about bacterial sexual reproduction - conjugation. However, one hypothesis concerning sexual reproduction in unicellular organisms is that such conjugation may be seen as the reverse of cell division. That means that the processes utilized to accomplish cell division have simply been reversed to accomplish sexual reproduction. This might require only a few mutations. Eukaryotes do not reproduce by conjugation, though: they produce haploïd gametes.

quote:

ORIGINAL: LadyEllen
Sexual reproduction has to be far more efficient than asexual, to provide this advantage in numerical terms.

In fact it is not. Asexual reproduction is far more efficient - and selfish: all progeny have the same genome as the single parent. So natural selection for these reasons would favor asexual reproduction. In fact there is at least one species of lizard that consists entirely of parthenogenic females; there are no males at all.

quote:

ORIGINAL: LadyEllen
As for the genetic advantage of combining sexually two identical single celled organisms - this is where things get interesting for steady state approaches. If the two individuals are identical, then their sexual offspring must also be identical to the parents, and thus no genetic advantage exists. If however, the two individuals are slightly variable, then their combination must necessarily produce a third which is differentiated from its parents. This difference can be advantageous or disadvantageous or neutral in the environment. Disadvantaged offspring would tend to less successful compared to the neutrals who would live on as their parents did, whilst the advantaged would be more successful than the neutrals, as long as the environment remained constant. Change in environment might later render the previously neutral more advantaged and leave the formerly advantaged at disadvantage - natural selection.

This is a good analysis. It is for this reason that natural selection favours sexual reproduction above asexual reproduction. Sexually reproducing species do not bet all on the same horse and evolve much faster than asexually reproducing species.

< Message edited by Rule -- 8/15/2006 6:30:36 AM >

(in reply to LadyEllen)
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