Dana Carvey on Darwin (NOT Dar-lose!)

"Dana Carey" should be "Dana Carvey".

And I don't know why people enjoy this video. It's not funny. And FWIW, the dodo went extinct long before Darwin ever came on the scene.

Check out Simpsons from Sunday. Flanders has fish with "Jesus" on them and Lisa asks how he did it.

Flanders: "Actually god made some fish that were pretty close to these, so naturally we selected those for further breeding."

Lisa: "So that natural selection was the ORIGIN of this species?"

Flanders: "Yep that's exactly, Woah haha...You almost got me."

While we're being technical, the catholics are not the ones with problems with evolution, Darwin didn't fence, Darwin wouldn't have faced off against catholic priests or dodo birds even if he could, yadda yadda. It's all a joke. Carvey's thing probably won't make sense unless you saw the most recent Sherlock Holmes movie, which was an action movie retelling of the normally incredibly sedate genre.

Not so much funny as determinedly silly. But has a good line or two: "A knee to HIS origin of species"; "behold the rise of man!"; "DarWIN, not DarLOSE." Um. The dodo being extinct long before Darwin is pretty much of a piece with the rest of the historical verisimilitude. It's a joke, Joyce.

Yes, it was mainly quoting from the recent Robert Downey - Jude Law Sherlock Holmes, but I saw bits of "Pirates of the Caribbean" in it, as well.

Bobo, humour is subjective - 14% of people agree with you according to the rating if that's any consolation.

And I don’t know why people enjoy this video. It’s not funny.

I have a morbid fear that AiG and the Disco Institute are going to claim it's a documentary.

Nick - It's up on YouTube also if that makes it easier to embed into your post?

http://thedispersalofdarwin.wordpress.com/2010/05/24/darwin-not-darlose/

That is seriously bent- perhaps even twisted.

Sincere question from someone who favors science but still has a couple of questions re: evolution/natural selection.

It seems to me that natural selection fails to explain why sexual creatures are preferred over "tri-sexual," "quad-sexual" or asexual creatures. I understand the argument that sexuality allows for diverse characteristics which favor the survival of at least some members of the species versus the cataclysmic extinction of all members of the species, but then why not three members or four members of species to reproduce . . . how much moreso . . . yes? And why not extinction? Why does sexuality spring forth -- and not tri-sexuality or quad-sexuality -- when asexual creatures clearly predominate the reproduction landscape? Is there something in the DNA that acts as a limitation? Is the DNA of an asexual creature structured the same as the double helix of sexual creatures? If so, then it would seem to also permit tri-sexual and quadsexual reproduction. (I realize I'm probably using the wrong words, i.e., tri-sexual and quad-sexual, but you know what I'm referring to . . . reproduction only by virtue of three distinct genders mating and reproduction only by virtue of four distinct genders mating).

I am confident that at least a couple folks out there can respond to my question intelligently, and I look forward to hearing from you. Thanks in advance.

You try getting three genders together, all in the mood at once.

Seriously, it never happened 'cause it's never had to. And it would be pretty complicated. Probably more complicated than any advantage gained.

As has been pointed out before, it's not really "survival of the fittest", it's "reproduction of the fit enough".

Since horizontal gene transfer has happened in asexual creatures, a lot, they could just as easily be termed omnisexual.

Sojourner said: Sincere question from someone who favors science but still has a couple of questions re: evolution/natural selection. It seems to me that natural selection fails to explain why sexual creatures are preferred over "tri-sexual," "quad-sexual" or asexual creatures. I understand the argument that sexuality allows for diverse characteristics which favor the survival of at least some members of the species versus the cataclysmic extinction of all members of the species, but then why not three members or four members of species to reproduce . . . how much moreso . . . yes? And why not extinction? Why does sexuality spring forth -- and not tri-sexuality or quad-sexuality -- when asexual creatures clearly predominate the reproduction landscape? Is there something in the DNA that acts as a limitation? Is the DNA of an asexual creature structured the same as the double helix of sexual creatures? If so, then it would seem to also permit tri-sexual and quadsexual reproduction. (I realize I'm probably using the wrong words, i.e., tri-sexual and quad-sexual, but you know what I'm referring to . . . reproduction only by virtue of three distinct genders mating and reproduction only by virtue of four distinct genders mating). I am confident that at least a couple folks out there can respond to my question intelligently, and I look forward to hearing from you. Thanks in advance.

John Kwok said: Sojourner, I'll try not to be as glib as fnxtr:

Sojourner said: Sincere question from someone who favors science but still has a couple of questions re: evolution/natural selection. It seems to me that natural selection fails to explain why sexual creatures are preferred over "tri-sexual," "quad-sexual" or asexual creatures. I understand the argument that sexuality allows for diverse characteristics which favor the survival of at least some members of the species versus the cataclysmic extinction of all members of the species, but then why not three members or four members of species to reproduce . . . how much moreso . . . yes? And why not extinction? Why does sexuality spring forth -- and not tri-sexuality or quad-sexuality -- when asexual creatures clearly predominate the reproduction landscape? Is there something in the DNA that acts as a limitation? Is the DNA of an asexual creature structured the same as the double helix of sexual creatures? If so, then it would seem to also permit tri-sexual and quadsexual reproduction. (I realize I'm probably using the wrong words, i.e., tri-sexual and quad-sexual, but you know what I'm referring to . . . reproduction only by virtue of three distinct genders mating and reproduction only by virtue of four distinct genders mating). I am confident that at least a couple folks out there can respond to my question intelligently, and I look forward to hearing from you. Thanks in advance.

But fnxtr is absolutely right. It made no sense to have more than two genders from an evolutionary perspective. As to why sexual selection is important, then just consider the evolutionary history of the Metazoa and Metaphyta. Both didn't begin to diversify rapidly until they were multicellular organisms capable of sexual reproduction. Sex acted as an "engine" of evolution, allowing both to diversify rapidly and to occupy hitherto unknown, vacant ecological niches.

On the other hand, I have read Dr Tatiana (Olivia Judson)on the sexes of slime moulds, and brother, there is a complicated subject. Slime moulds, like all isogamous organisms, produce "sex cells" of many different types. In effect, they are, each one, not only hermaphrodite, but many different sexes, all at once.

Dave Luckett said: On the other hand, I have read Dr Tatiana (Olivia Judson)on the sexes of slime moulds, and brother, there is a complicated subject. Slime moulds, like all isogamous organisms, produce "sex cells" of many different types. In effect, they are, each one, not only hermaphrodite, but many different sexes, all at once.

Mr. Kwok's 2nd response WAAAY over my head.

With respect to Mr. Kwok's 1st response, i.e., that "it made no sense to have more than two genders from an evolutionary perspective," and fnxtr's response, i.e., tri-sexual and quad-sexual reproduction never happened because it never had to and would probably be more complicated than any advantage gained," I've got to cry "Boulderdash!" Evolution is chance . . . observed over time. "Sense" appears to be a word more suited for intelligent design. For every genetic difference that helped a species survive, there is, by chance, another genetic difference that helped a species perish. Those which survived moved on to the next generation, but not by "any sense," they moved on because of a chance relationsip to the environment. And to say that tri-sexual and quad-sexual reproduction never happened "because it never had to" is to beg the question much like a theist would do. Sexual reproduction "never had to" happen. There is no reason why life could not consist of three or four species of asexual creatures; diversity is not required . . . only survival based on a chance realtionship with the environment. And it is simply no answer to postulate/speculate that tri-sexual and quad-sexual reproduction would probably be more complicated than any advantage gained; e.g., if my grandmother had wheels, she would probably be a bicycle -- but so what?

A big thank you to Mr. Luckett for acknowledging the complexity of the issue.

I am hoping, however, that there will be further responses (but if a response is as complex as Mr. Kwok's 2nd response, I hope the wording will at least be dumbed down a bit for those of us who can think, but do not come to the discussion with a strong scientific background to lean upon).

Sojourner said: Evolution is chance . . . observed over time.

Sojourner said: Mr. Kwok's 2nd response WAAAY over my head. With respect to Mr. Kwok's 1st response, i.e., that "it made no sense to have more than two genders from an evolutionary perspective," and fnxtr's response, i.e., tri-sexual and quad-sexual reproduction never happened because it never had to and would probably be more complicated than any advantage gained," I've got to cry "Boulderdash!" Evolution is chance . . . observed over time. "Sense" appears to be a word more suited for intelligent design. For every genetic difference that helped a species survive, there is, by chance, another genetic difference that helped a species perish. Those which survived moved on to the next generation, but not by "any sense," they moved on because of a chance relationsip to the environment. And to say that tri-sexual and quad-sexual reproduction never happened "because it never had to" is to beg the question much like a theist would do. Sexual reproduction "never had to" happen. There is no reason why life could not consist of three or four species of asexual creatures; diversity is not required . . . only survival based on a chance realtionship with the environment. And it is simply no answer to postulate/speculate that tri-sexual and quad-sexual reproduction would probably be more complicated than any advantage gained; e.g., if my grandmother had wheels, she would probably be a bicycle -- but so what? A big thank you to Mr. Luckett for acknowledging the complexity of the issue. I am hoping, however, that there will be further responses (but if a response is as complex as Mr. Kwok's 2nd response, I hope the wording will at least be dumbed down a bit for those of us who can think, but do not come to the discussion with a strong scientific background to lean upon).

"so 3 might have a genetic advantage of “stirring the pot” to favor variation, but starts to see diminishing returns coupled with the complexity in the..."
...the mating rituals (getting 3 variables together)

I have no hidden agenda Mr. Luckett. Please feel free to substitute your sentence, "Evolution is the effects of selection on variation, observed over generational time," for my errant sentence that evolution is chance observed over time. With your substitution in tow, my argument is not lessened. In fact, assuming your correction to be accurate (and I have no reason to believe otherwise), my argument remains not only steadfast, but is now more scientifically accurate.

I mean, if we discover that there is life on one of Saturn's moons, in the oceans underneath frozen ice . . . and we discover that the life found there consists of three to four species of asexual creatures . . . then we must ask: "Why sexual creatures on Earth?" And since we can identify a point in the time/space continuum when life on Earth consisted of solely asexual creatures, that then raises the same question: "Why sexual creatures on Earth?"

And why only two genders?

Torbach said: ...so 3 might have a genetic advantage of “stirring the pot” to favor variation, but starts to see diminishing returns coupled with the complexity in the mating rituals. It might be prudent to note a philosophical duality observed in the universe. Why only a North and South poles in magnets? + and - charge?

Sojourner said: The same can be said of 2; that is, so 2 might have a genetic advantage of “stirring the pot” to favor variation, but starts to see diminishing returns coupled with the complexity in the mating rituals. I have also thought of the "duality" explanation; except most duality issues, matter/antimatter, light/dark, postive/negative charge, etc., etc., are usually polar opposites. This is not exactly the same thing when we are talking about gender differences.

Torbach said: Sexual variation has many advantages at times and 2 is the MINIMUM for that advantage, there is little advantage to gain to 3 due to it costing more energy conserved and giving less of a return. In nature, what is easiest physically/electrically/thermal(y) is selected for.

Torbach said: Check out Simpsons from Sunday. Flanders has fish with "Jesus" on them and Lisa asks how he did it. Flanders: "Actually god made some fish that were pretty close to these, so naturally we selected those for further breeding." Lisa: "So that natural selection was the ORIGIN of this species?" Flanders: "Yep that's exactly, Woah haha...You almost got me."

Sojourner's argument (that there should be more than two sexes, if evolution is true) has two responses.

Firstly, if the sample is "all living things", there are indeed examples of more than two "sexes", the difficulty being what is defined as "sex" in the sense of gender.

Secondly, for the selection for more than two sexes to be made, there must be advantages to that arrangement that are greater than the disadvantages. The advantage of greater genetic diversity from having more than two sexes, all contributing genes, over only two, is, on the face of it, more than cancelled out, for animals and plants, by the added difficulty and costs of finding a third partner and the energy costs involved.

Hence, for Soujourner's conjecture to be made out, it would be necessary to demonstrate the converse in animals and/or plants. I can only suggest that he design and undertake a suitable experiment.

I have invoked benfords law, and when you see a spiral grow you are seeing Fibonacci. So i (obviously) find the conclusion of 2 being the minimum to satisfy the sexual act (thereby granting a nearly infinite amount more of variation than a daughter) as perfectly logical since minimums tends to be natures way.

2nd of all i'm curious what would be your hypothesis as to a 3rd gamate?
egg, sperm... and?
so the idea; 3 gametes come together at the same time, but what in nature have you observed that leaves you to guess a 3rd gamete would be so much better?

also 3 comes after 2.
if two dominates, three wont be selected for.

the solution i think is right there,
2 is first, easier and way more genetic variation than asexual.

but Dave already mentioned that some molds just sit and have multi gender capacity.. obviously it "works" for them and fungi have "genetic markers" very different than genders..

id also like to invoke other lateral answer to your question

you COULD say that Bees have 3 social genders.
a queen, males, drones

there are certain Fish, i saw cuttle fish have i guess you'd call em alpha and beta males.. the beta makes it self look like a female and tricks alpha male during their protection rituals. Both end up fertilizing the same female.

i think you may be running into a limit of human knowledge.it is also safe to say humans have investigated fractions of a % of the life in earths history,
so be patient? ;p

For the record, I doubt that Mr. Byers and I would see eye-to-eye on virtually anything.

6.5 for the Byergabble. Quite high on the ignorance segment, but not really incoherent, although "selection goes runs with the poasitive change" has undoubted merit. About average on the idiocy scale, for Byers.

I commented that during the “sexual revolution” of asexual creatures, surely there must have been some sort of variation-spawning asexual reproduction which is responsible for producing sexual creatures? That seems logical. Since we began with X, and ended up with X and Y, X must in some way be responsible for producing Y -- a significant variation from X, if one is asexual and the other sexual.

Do we have any idea what happened to produce Y when, but the very moment before Y, all we had was X?

you know some humans do end up with changes in the usual XX or XY... they happen all the time
think of something like down syndrome? it just isn't an advantage.. yet?

For that matter, there are women with three X chromosomes. They, too, are not reproductively advantaged - the condition often, though not always, leads to sterility.

I'm still pondering the symbol that should be on the door of asexual organisms' public toilets. ;o)

Since this thread was about science and humour, you'd might enjoy this:

http://www.newsbiscuit.com/2010/05/25/synthetic-life-form-accuses-god-of-playing-science/

Sojourner said: The same can be said of 2; that is, so 2 might have a genetic advantage of “stirring the pot” to favor variation, but starts to see diminishing returns coupled with the complexity in the mating rituals. I have also thought of the "duality" explanation; except most duality issues, matter/antimatter, light/dark, postive/negative charge, etc., etc., are usually polar opposites. This is not exactly the same thing when we are talking about gender differences.

Sojourner--

Going back to square one in evolutionary theory, I'm assuming you understood the reason Dave Luckett changed your definition of evolution ("chance") to "selection on variation" is that the variation part, mutation, can be called chance, but selection is anything but chance; it cuts away less adapted life forms without mercy.

So, I think it can be accurately-- if counterintuitively-- said that extra sexes mutate into existence all the time-- XXX's, YYX's, (no Y)X's, and so on. But they either can't reproduce or reproduce much less well than us standard, old YX's and XX's. Consequently, they're eliminated by natural selection. (Species, with the exception of some rotifers, that don't have sex tend to go along gangbusters for a while, and then succumb.)

As I recall, birds, which of course have two sexes, have, genetically, a different two sexes from us mammals. So mutations don't seem to have any trouble inventing new sexes. It's natural selection that favors two.

PS-- You really should read "Dr. Tatiana's Sex Advice to All Creation" by Olivia Judson. Lots of fun, and lots of good information there.

Sojourner said: surely there must have been some sort of variation-spawning asexual reproduction which is responsible for producing sexual creatures?

Do we have any idea what happened to produce Y when, but the very moment before Y, all we had was X?

Sojourner -

You may be lacking some background knowledge that will help you as you ponder your question. If you already knew this stuff, a review won't hurt. If you didn't, and your curiosity is sincere, learning some basics will massively increase your ability to conjecture in an intelligent way about biology.

I often use links from Wikipedia to introduce or even review the basics. Major errors are usually corrected quickly, and good articles contain strong reference sections for those who wish to go deeper. Wikipedia is imperfect but is convenient and solid.

Briefly, prokaryotes are the small-celled bacteria and archae that make up a vast proportion of the biomass on earth. http://en.wikipedia.org/wiki/Prokaryotes. I feel that this article is incomplete, as it does not contain sufficient coverage of genetics, but it is a good summary of prokaryotic cellular structure.

Their genomes are almost always haploid - nearly always one major chromosome.

They have a lot of "lateral" transfer of genes - DNA structures like plasmids are exchanged from cell to cell. But when they reproduce they rely on binary fission. http://en.wikipedia.org/wiki/Binary_fission

Eukaryotes are the larger celled organisms like plants, fungi, and animals. http://en.wikipedia.org/wiki/Eukaryotes. Many eukaryotes are truly multicellular.

Eukaryotic baseline genomes are nearly always polyploid - more than one copy of each chromosome - with diploid (two copies of each) being the most common, especially if we are not talking about plants. I say "baseline genomes" because haploidy can be seen in individuals, especially in insect species, but the overall reproductive strategy of even species where this occurs is typically based in diploidy.

Individual eukaryotic cells can reproduce in a process which is analogous to binary fission, known as mitosis. http://en.wikipedia.org/wiki/Mitosis

However, the cells that are specialized for reproduction can also divide and recombine in a process known as meiosis. http://en.wikipedia.org/wiki/Meiosis

Getting down to the question - as you can see, being diploid is a minimum requirement for meiosis. However, other degrees of polyploidy would not necessarily inhibit meiosis (and in fact, often do not).

As you can also see, cell division is binary in nature throughout nature.

A parent cell dividing into "n" descendants, unless "n" is expressable as 2^m, where "m" is an integer, in a way that balances genetic material sufficiently for more than one viable, normal offspring cell, would be very difficult, given the mechanisms of reproduction that have evolved. Of interest, my major field of expertise is pathology, and in tumors, we do see abnormal "tripolar mitoses" from time to time. Such mitoses may result in either no viable descendant cells, or in one or more descendant cells which are highly abnormal and undifferentiated.

It would seem that a variety of barriers to non-binary cellular reproduction have existed, and been selected for, throughout life's history.

(There is no reason to doubt your sincerity, but I will note one other benefit of bringing the actual technical details to the table. The process serves as an exceptionally powerful troll repellent.)

Not being a biologist I'm finding this discussion interesting if at times a bit over my head. My sole contribution to this discussion is simply to whimsically mention that Isaac Asimov wrote a sci fi story about (among other things) aliens with 3 sexes, called The Gods Themselves. I highly recommend it for entertainment value, but not for biology - the aliens live in another universe with different physical laws.

Dave Luckett said:

Sojourner said: Evolution is chance . . . observed over time.

(The ellipsis is as the original. I have no idea why it's there.) No, it's not. Evolution is the effects of selection on variation, observed over generational time. The idea that evolution is chance is a creationist staple, but it is blatantly false to fact, and long known to be so. That Sojourner is capable of so obviously false a statement leads me strongly to suspect the provenance of his ideas and the motivation for his presence here.

hoary puccoon said: As I recall, birds, which of course have two sexes, have, genetically, a different two sexes from us mammals.

Robert Byers said:

Torbach said: Check out Simpsons from Sunday. Flanders has fish with "Jesus" on them and Lisa asks how he did it. Flanders: "Actually god made some fish that were pretty close to these, so naturally we selected those for further breeding." Lisa: "So that natural selection was the ORIGIN of this species?" Flanders: "Yep that's exactly, Woah haha...You almost got me."

I love the simpsons. Its the only funny show. Ned Flanders is the first Born -again type of christian ever on t.v. Anyways this brings up a point. Evolution is not wrong because of selection concepts. Artificial or natural. Its wrong and beyond possible because it claims organs/skeleton/ looks etc are all created from chance , positive, mutations . Then selection goes runs with the poasitive change. Its the idea of organ etc after organ from a bug to a buffalo in all fantastic complexity coming out of nowhere that is the absurdity of evolutions attempts to contribute to biology. Its not about tiny selections on different coloured bugs. Its about claims to origins of the the complexity of biology. Due to time issues selection on even minor points is also suspect. Yet possible like in the amazon even today. Cartoons are not a good way to deal with origin issues. On the other hand i guess not much difference from most paid evolutionists. Off the record.

fnxtr said: Sort of. IIRC, in birds the gender is determined by the ovum, not the sperm.

MrG said:

fnxtr said: Sort of. IIRC, in birds the gender is determined by the ovum, not the sperm.

Yeah. Femmes have ZW chromosomes, males have ZZ chromosomes. And then there are reptilians where the sex is determined by how warm the eggs are.

Robert Byers said: Anyways this brings up a point. Evolution is not wrong because of selection concepts. Artificial or natural. Its wrong and beyond possible because it claims organs/skeleton/ looks etc are all created from chance , positive, mutations . Then selection goes runs with the positive change. Its the idea of organ etc after organ from a bug to a buffalo in all fantastic complexity coming out of nowhere that is the absurdity of evolutions attempts to contribute to biology.

Sojourner said: I commented that during the “sexual revolution” of asexual creatures, surely there must have been some sort of variation-spawning asexual reproduction which is responsible for producing sexual creatures? That seems logical. Since we began with X, and ended up with X and Y, X must in some way be responsible for producing Y -- a significant variation from X, if one is asexual and the other sexual. Do we have any idea what happened to produce Y when, but the very moment before Y, all we had was X?

J. Biggs,

Parthenogenesis has also been induced in frogs, as far back as the 1920's(!). But AFAIK its never been induced in mammals.

Human parthenogenesis crops up in sci-fi from time to time. Does no conception mean no soul? ;)

Great stuff. Like most genuine answers, the answer ain't easy. Some of the assumptions I brought to the discussion were simply wrong. The various alternatives then branch into surprising directions. Much study is needed to understand some of the subtle and even not-so-subtle differences. In the end, the ground has been well plowed and has yielded great harvests of knowledge . . . knowledge which I now have to read up on to gain the insights of great minds who have studied the subject in excruciating detail. My hat's off to all of you. Thank you.

eric said: J. Biggs, Parthenogenesis has also been induced in frogs, as far back as the 1920's(!). But AFAIK its never been induced in mammals. Human parthenogenesis crops up in sci-fi from time to time. Does no conception mean no soul? ;)

My previous comment should have read, "does not occur naturally in mammals."

Robert Byers said: I love the simpsons. Its the only funny show. Ned Flanders is the first Born -again type of christian ever on t.v. Anyways this brings up a point. Evolution is not wrong because of selection concepts. Artificial or natural. Its wrong and beyond possible because it claims organs/skeleton/ looks etc are all created from chance , positive, mutations . Then selection goes runs with the poasitive change. Its the idea of organ etc after organ from a bug to a buffalo in all fantastic complexity coming out of nowhere that is the absurdity of evolutions attempts to contribute to biology. Its not about tiny selections on different coloured bugs. Its about claims to origins of the the complexity of biology. Due to time issues selection on even minor points is also suspect. Yet possible like in the amazon even today. Cartoons are not a good way to deal with origin issues. On the other hand i guess not much difference from most paid evolutionists. Off the record.

this thread is sufficiently off topic that i don't mind deflecting it further w/ wild imaginings (partly sparked by the two vs. three sex discussion).

does anyone know why we aren't centaurs? in other words, why are tetrapods tetrapods and not hexapods? i'm not sure if this is something that can be investigated or just speculated about. loss or gain of prehensile tails might suggest something one way or another but i know nothing about it.

my guess would be that it's just not how the dice turned up this time around, but i was wondering if anyone had other insight.

It is not exactly parthenogenesis, but in this novel Jesus has a half-sister: she has a father but no mother. I don't remember it well, but you have to read very carefully to get all the allusions, and I am sure I missed a lot. The father, I think, was celibate.

why are tetrapods tetrapods and not hexapods?

Open here I flung the shutter, when, with many a flirt and flutter,

In there stepped a stately Raven of the saintly days of yore.

Not the least obeisance made he; not a minute stopped or stayed he,

But, with mien of lord or lady, perched above my chamber door--

:)

birds, which of course have two sexes, have, genetically, a different two sexes from us mammals. So mutations don’t seem to have any trouble inventing new sexes. It’s natural selection that favors two.

"PS-- You really should read "Dr. Tatiana's Sex Advice to All Creation" by Olivia Judson. Lots of fun, and lots of good information there."

Fabulous book---maybe my favorite ever.

Even if something sounds like a good idea and even if it would work if it happened, doesn't mean it's within reach by accumulative small genetic changes from what is.

As for the notion of more than two eyes in chordates, my thought is that maybe eyes are more expensive in the chordate system than they are in the arthropod or mollusk systems. For more than two pairs of limbs in species with internal skeletons causes pretty much the same thought.

Henry

Trial lawyers often comment that they do not select a jury; rather, they deselect a jury (i.e., jurors are impanneled, and then each side is given a certain number of challenges to deselect members). It sounds like natural selection may, likewise, be natural deselection. That is, random mutations create variations and then the environment deselects those variations which are too unfit to carry on. No real selection; just uncompromising deselection.

That's one of the factors that are involved. Another factor is the feedback loop from repeated mutations and selection effects, each acting on the results from the previous cycles.

eliminating failure is selection just as much as an inventor doesn't invent, but rather find ways things don't work...from a point of view things work deductively.

geology is a process of change and "environment" on earth is a sum of animals simultaneously competing. Both positive and negative enforcement, an opposite and equal reaction.

Trial lawyers often comment that they do not select a jury; rather, they deselect a jury (i.e., jurors are impanneled, and then each side is given a certain number of challenges to deselect members). It sounds like natural selection may, likewise, be natural deselection. That is, random mutations create variations and then the environment deselects those variations which are too unfit to carry on. No real selection; just uncompromising deselection.

harold said: "If an allele is associated with a phenotype that leads to reproductive disadvantage, the effect of natural selection will be to reduce the frequency of that allele in the population."

Sojourner said:

harold said: "If an allele is associated with a phenotype that leads to reproductive disadvantage, the effect of natural selection will be to reduce the frequency of that allele in the population."

To this premise, I added the premise: "A phenotype which requires two members of a species to reproduce (sexual reproduction) is at a reproductive disadvantage to a phenotype which requires only one member to reproduce (asexual reproduction)." The conclusion, of course, was that sexual creatures appear to be an anathema to Darwin's theory of natural selection. And to the extent someone responds that requiring two members of a species to reproduce instead of just one is actually a reproductive advantage, then logic would suggest three members of a species more advantageous than two. Of course, in light of everything that's been contributed to this topic, I am now content to set aside my hastey, ignorance-laden conclusions to instead study up on the issue. There is a lot of ground that needs to be covered. Clearly, it is a lot more complex than I had originally envisioned.

Malchus said: In order to combine genetic material or other developmental contributions from multiple parents would require an entirely new inheritance mechanism.

To this premise, I added the premise: “A phenotype which requires two members of a species to reproduce (sexual reproduction) is at a reproductive disadvantage to a phenotype which requires only one member to reproduce (asexual reproduction).”

The conclusion, of course, was that sexual creatures appear to be an anathema to Darwin’s theory of natural selection.

And to the extent someone responds that requiring two members of a species to reproduce instead of just one is actually a reproductive advantage, then logic would suggest three members of a species more advantageous than two.

Of course, in light of everything that’s been contributed to this topic, I am now content to set aside my hastey, ignorance-laden conclusions to instead study up on the issue. There is a lot of ground that needs to be covered. Clearly, it is a lot more complex than I had originally envisioned.

But isn’t that exactly what happened when the asexual creature underwent mutation to allow an entirely new (sexual) inheritance mechanism?

Sojourner said:

Malchus said: In order to combine genetic material or other developmental contributions from multiple parents would require an entirely new inheritance mechanism.

But isn't that exactly what happened when the asexual creature underwent mutation to allow an entirely new (sexual) inheritance mechanism?

Maybe I'm getting too grouchy again, lol.

I don't really conceive modern sexual reproduction as having arisen due to a single mutation (especially since there are several different types). But whatever...

Harold: I'm not trying to create a straw man just to knock him down. I think this probably one of those areas that, as you put it, I "really need to study up on the background material."

If you want to jump to a conclusion about me, please jump to the conclusion that I'm stupid on a lot of these issues -- not so stupid in my professional area of expertise I might add, but I am admittedly stupid concerning evolutionary theory -- as opposed to concluding that I'm surreptitiously trying to hammer home some sort of a point one way or the other.

These topics are often discussed among lay people but very few of us have the expertise shared by regular contributors of the Panda's Thumb. When I used to attend church a lot, I was often looked down upon because I did not so quickly "join in" with whatever the masses were saying. It is one of the social avenues employed by churches to do their own "selecting." I would like to think the scientific community is much better than my local church when it comes to dealing with those of us who have legitimate questions.

And yes, I agree that “if two is better than one, then three is necessarily better than two” is NEVER sound logic. But it did take you to point it out to me; when I first thought of it, it sounded okay rattling around in my empty skull. It is like the easy logical leap we make when we attribute the pre-event occurrence as the CAUSE of the event itself. Temporal succession proves nothing. Else light would cause dark and dark would cause light. Nevertheless, in everyday use, it is a quick conclusion even the brightest among us leap to from time to time (depending on the subject matter).

Click this link to access On the Origin of Sexual Reproduction without charge. Eric had mentioned earlier that a good source was Carl Zimmer’s “On the Origin of Sexual Reproduction,” [Science 5 June 2009: Vol. 324. no. 5932, pp. 1254 - 1256] but added that "you’ll need a subscription to read it." I found it online for free at carlzimmer.com.

A big thank you to Eric, J. Biggs and Harold for the great references and links to wikipedia. And so many people recommended Olivia Judson's, "Dr. Tatiana’s Sex Advice to All Creation," that I was compelled to order a copy. Everyone has been most helpful. Now I've got some reading to catch up on. Many thanks again.

Sojourner said: And so many people recommended Olivia Judson's, "Dr. Tatiana’s Sex Advice to All Creation," that I was compelled to order a copy.

Sexual reproduction allows beneficial (or neutral) mutations from different sub-populations to be combined, in several different ways. This in turn allows a species to adapt more quickly to a changing environment, as compared with a species that can't routinely recombine DNA from multiple lineages.

If the environment includes parasites, then routine recombination makes the species a moving target, figuratively speaking, since a parasitic species would have to adapt to the faster changes, and wouldn't have that issue with an asexually reproducing victim species.

I don't think more than two genders would add much to that benefit, even if it didn't increase the cost of reproduction, since with two the ability to mix changes from separate lineages is already there.

Henry

Sojourner, you may also want to look up r/K reproduction theory.

Basically, there are (at least) two different strategies for spreading genes: create a lot of offspring, or create relatively fewer offspring which are much better at competing. Your comment about sexual reproduction being disadvantageous compared to asexual cloning would only apply if r-type strategies were the only ones that matter. But they aren't. An asexual critter that creates many offspring in a time period may be out-competed by a sexual critter that produces far fewer (because it has to find mates), as long a sex permits the creation of much fitter children.

A bit of background information for Sojourner...
If you're new to the Creation/evolution 'culture war', you are probably not fully cognizant of the sheer level of duplicity/deceit that is exhibited by Creationists on a routine basis. In particular, you probably don't know that it is far from uncommon for Creationists to pretend that they're just ordinary seekers of truth, motivated by nothing but honest curiosity, but they have just one little question about this 'evolution' thingie... and their 'just one little question' just happens to be Yet Another Hoary Old Anti-Evolution Argument from straight out of the Creationist playbook.
Now, someone who merely asks a question certainly could be an ordinary seeker of truth, motivated by nothing but honest curiosity, who sincerely wants to know the answer to their question and will be satisfied with that answer. But when it's a Creationist running a 'false flag' operation, that's a horse of a different gear ratio. Rather than reacting as an honestly curious person might (by, say, thanking the people who provided the answer they asked for), a Creationist-in-truthseeker's-clothing will react in a manner which puts the lie to their gosh-I'm-just-a-curious-layman façade. This reaction could be "Oh, sure, but what about [list of 57 more questions]? Huh? Huh?" -- that is, the celebrated Gish Gallop (which means they were lying about "just one simple question"). This reaction could be "No, that can't be right, because [insert Creationist counter-argument to the answer given]!" (which means their "just an innocently curious person" guise was a lie right from the start, seeing as how Creationist counter-arguments tend to be utterly unknown to anybody except people who have been aroung the Creationism/evolution block a few times already). This reaction could be... well, however the Creationist-in-truthseeker's-clothing reacts to having their question answered, it's a pretty damned good bet that their reaction will be utterly characteristic of Creationists, and not at all consistent with the demeanor of an honestly curious person.
This sort of thing is, to repeat, far from uncommon. So it's understandable that some of us on the pro-science side of the fence might get a little impatient with ostensible newcomers who profess to have "just one little question" about evolution, because in all too many cases previously, people who fit that profile have, in the fullness of Time, revealed themselves to be goddamned lying Creationists with a hidden agenda; it's understandable that some people on the pro-science side of the fence might be a wee bit too quick to dismiss an ostensible truthseeker as a falsely-flagged Creationist. But while it's understandable, it's also not desirable, because who knows how many genuine curious laymen might get burned by knowledgeable people whose bad experiences with lying Creationists have predisposed them to treat everyone who says "Hey, I got a question about evolution..." as if that question was a lying Creationist's deceitful pretext?

Sojourner wrote:

"Of course, in light of everything that’s been contributed to this topic, I am now content to set aside my hastey, ignorance-laden conclusions to instead study up on the issue. There is a lot of ground that needs to be covered. Clearly, it is a lot more complex than I had originally envisioned."

You are correct. Indeed, this is one of the most interesting topics in all of biology and one where an evolutionary approach is absolutely required. The references recommended seem good and of course Carl Zimmer is usually great at explaining complicated issues. I have found that one of the best technical treatments of this topic is The Evolution of Sex by John Maynard Smith, it is an oldie but a goodie. You can order used copies on Amazon for $22 (US):

www.amazon.com/Evolution-Sex-John-Maynard-Smith/dp/0521293022

One important thing to notice is that most species reproduce sexually and no truly asexual lineages are either ancient or evolutionary successful. So, whether anyone truly understands exactly why or not, sexual reproduction does indeed seem to be evolutionary advantageous, at least in the long run.

Also notice that, just as with life, issues regarding the origin of sex are somewhat different than those regarding the maintenance of sexual reproduction.

There is one exception to the rule that, as DS says, "no truly asexual lineages are either ancient or evolutionary successful." Those are the Bdelloid rotifers, which number over 300 species.

For years, the Bdelloidea's ability to survive and speciate without sex has been a puzzle. One clue is that Bdelloidea can basically dry up and form a cyst when conditions don't suit them. It was thought perhaps that was enough to escape dangerous parasites. But recently, Matthew Meselson's* group at Harvard discovered that when Bdelloids come back to life, so to speak, after having dried up for a while, they incorporate any stray DNA strands that happen to be around. So, even though Meselson's group found persuasive evidence that Bdelloids aren't sexual, they also found evidence that Bdelloids do have a way to get new genetic material. That would truly be the exception that proves the rule.

(*I believe that's the same Meselson who, with F. Stahl, performed "the most beautiful experiment in biology," which provided the first experimental support for the double helix model of DNA.)