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A chimp-pig hybrid origin for humans?

m.phys.org

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Re: A chimp-pig hybrid origin for humans?

#41

Post by twstws »

goldfeld wrote: post #31
twstws wrote: post #18

Earlier quoted context omitted.

This. The author makes the absurd claim that because many hybrids are fertile, any hybrid could be fertile. Using hybridization between two closely related birds to support the notion that pigs and apes could breed is ridiculous.

The scientist behind this hypothesis makes no such claim: "For my own part, curiosity has carried me away from my old idea of reality. I no longer know what to believe. Is it possible that so many biologists might be wrong about the nature of human origins? Is it possible for a pig to hybridize with a chimpanzee? I have no way of knowing at present, but I have no logical or evidential basis for rejecting the idea. Be…

He makes the argument on his website: http://www.macroevolution.net/human-origins.html#at_pco=cfd-...

1 people think hybrids are sterile, but they're not 2 people think hybrids don't occur in nature, but they do 3 people think only plants hybridize, but animals do to

From this basis, he concludes that a chimp-pig hybrid is plausible, and proceeds to lay out his theory.

The problem is the three facts he starts with are trivial compared to the obstacles raised by PZ Meyer. To take just one, there is the difference in chromosome number. In most cases, if a human ends up with the wrong number of chromosomes, it's a lethal condition. Or you end up with Down's syndrome. With one extra chromosome. The hybrid this guy posits has a dad with 38 chromosomes and a mom with 48.

I could argue that that's not a big deal. In the plant groups I study stranger things happen. But that's in plants. Primates, as I understand it, are much more sensitive to chromosomal abnormalities.

There are many logical, evidential reasons to discount this hypothesis. Again, check out the pz meyer post linked elsewhere. Claiming I don't understand evolution because "given enough tries anything is possible" is facile. Of course anything is possible. But what is probable here?

Re: A chimp-pig hybrid origin for humans?

#42

Post by darkmighty »

a-priori wrote: post #20
gus_massa wrote: post #15

Earlier quoted context omitted.

Many hybrids are infertile. There are some documented cases of fertile hybrids in very related animals and very related plants (plants are weird!). http://en.wikipedia.org/wiki/Hybrid_(biology)#Hybrid_species But and hybrid between a chimp and a pig: simply no way! Even creating a live pig-chimp hybrid is probably almost impossible, a fertile pig-chimp hybrid would be a miracle.

It doesn't matter that fertile hybrids are unusual. For evaluating this theory, it only has to be possible to produce a fertile chimp-pig hybrid. Then, given a large number of chimp-pig... interactions, you can then assume that eventually one would be successful. (That said, before you interpret this as me supporting the theory, please read my top-level comment)

Nope, possibility is never enough evidence (disregarding likelihood). The old tale from thermodynamics: "Entropy tends to it's maximum. In reality there is a chance that all air in the room will concentrate in a small spot and entropy will decrease; how often did you see that happening?"

Re: A chimp-pig hybrid origin for humans?

#43

Post by embolism »

twstws wrote: post #16
thelibrarian wrote: post #6

There's at least one fairly well-know biology professor/blogger who is unimpressed with what he dubs the "MFAP" hypothesis: http://freethoughtblogs.com/pharyngula/2013/07/02/the-mfap-h...

The thing I find most depressing about these crackpots is that some otherwise productive scientist has to spend an evening debunking their nonsense. And it still doesn't stop. I taught evolution for undergrads, and occasionally had to deal with these issues from students. It takes time to look into them, and no matter how thoroughly debunked the theory, some kids find them too irresistible to let go of. It undermines…

If it's really crackpot then it should be easy to point out a clear flaw without taking much time.

Re: A chimp-pig hybrid origin for humans?

#44

Post by eli »

GuiA wrote: post #10

"These days, getting a Ph.D. is probably the last thing you want to do if you are out to revolutionize the world. If, however, what you propose is an idea, rather than a technology, it can still be a valuable asset to have." Man, those newspapers' opening lines are getting worse and worse...

Phys.org ain't a newspaper.

Re: A chimp-pig hybrid origin for humans?

#45

Post by hetman »

nitrogen wrote: post #36
hetman wrote: post #35

Earlier quoted context omitted.

What often distinguishes the crackpot from the visionary is whether they are eventually vindicated. The latter usually begins their career being perceived as the former.

This is a tautology. Of course visionaries are the ones who were vindicated. That doesn't mean that being perceived as a crackpot is a reliable indicator of being a visionary. It's similar to the argument that opposition equals confirmation -- some religious groups and conspiracy theorists argue that the fact that people oppose them means they are right.

I never said crackpots are guaranteed to be visionaries, though I'm sure it made a convenient strawman for you to argue against. My only point was that you can't be certain either way a priori, to be sure you must actually investigate it (and history tells us even then that's not always going to guarantee certainty).

Re: A chimp-pig hybrid origin for humans?

#46

Post by goldfeld »

twstws wrote: post #41
goldfeld wrote: post #31

Earlier quoted context omitted.

The scientist behind this hypothesis makes no such claim: "For my own part, curiosity has carried me away from my old idea of reality. I no longer know what to believe. Is it possible that so many biologists might be wrong about the nature of human origins? Is it possible for a pig to hybridize with a chimpanzee? I have no way of knowing at present, but I have no logical or evidential basis for rejecting the idea. Be…

He makes the argument on his website: http://www.macroevolution.net/human-origins.html#at_pco=cfd-... 1 people think hybrids are sterile, but they're not 2 people think hybrids don't occur in nature, but they do 3 people think only plants hybridize, but animals do to From this basis, he concludes that a chimp-pig hybrid is plausible, and proceeds to lay out his theory. The problem is the three facts he starts with ar…

I think we agree it's highly improbable, but then all major leaps of life and evolution have been. From that ground, I don't see why you seem to be angry at the guy for making a (minimally plausible, not because of the obstacles, but because of what the theory would explain) leap of faith and then wanting to prove his way there scientifically, tagging the whole ordeal 'absurd' and 'ridiculous.'

Sure the hybrid has parents wildly different genetically. But if two individuals who have a high chance of producing fit offspring may by chance produce unfit individuals, then we also agree the hybrid would have to have been a minimally fit individual by chance born from two parents who have a very low chance of doing so. A person with Down syndrome is not a catastrophe of nature, and not fundamentally a disease, such that through successive backcrossing (women with Down syndrome are usually fertile) it could theoretically produce a different kind of Homo that would be fit for some imaginary environment conditions. Or at least would still be a far more intelligent creature than all other animals we have on this planet.

Re: A chimp-pig hybrid origin for humans?

#47

Post by twstws »

goldfeld wrote: post #46
twstws wrote: post #41

Earlier quoted context omitted.

He makes the argument on his website: http://www.macroevolution.net/human-origins.html#at_pco=cfd-... 1 people think hybrids are sterile, but they're not 2 people think hybrids don't occur in nature, but they do 3 people think only plants hybridize, but animals do to From this basis, he concludes that a chimp-pig hybrid is plausible, and proceeds to lay out his theory. The problem is the three facts he starts with ar…

I think we agree it's highly improbable, but then all major leaps of life and evolution have been. From that ground, I don't see why you seem to be angry at the guy for making a (minimally plausible, not because of the obstacles, but because of what the theory would explain) leap of faith and then wanting to prove his way there scientifically, tagging the whole ordeal 'absurd' and 'ridiculous.' Sure the hybrid has pa…

This bothers me as a former professor, because these fringe ideas undermine teaching and waste time. Imagine trying to present a lesson on evolution, and one of your students brings this up. You spend a few minutes discussing it. Of course, you've never heard of it before, because it's beyond implausible. So you spend your evening looking into it, and the holes in the theory. Next class you spend more time discussing it. If you're good, the student understands and you move on. If not the student leaves thinking this is a valid alternative viewpoint. And no, an idea does not become valid simply because it's not impossible. It's not unreasonable to demand more than a faint hope probability before judging an idea worth serious discussion.

This happens once, and you can make it a teachable moment. But when the scenario starts to repeat itself it undermines the effort you're putting into teaching real science.

Re: A chimp-pig hybrid origin for humans?

#48

Post by a_bonobo »

nealabq wrote: post #38

Jean Auel's The Clan of the Cave Bear book-series explores the possibilities of Neanderthal/Cro-Magnon interaction, but this article brings up a whole new set of intriguing plot twists.

So far, there are two proven gene-flow events to Homo sapiens from non-sapiens: Homo neanderthalensis and from the Denisova hominin population. In the latter case science isn't sure yet whether the Denisova hominin was a sub-species or species.

http://en.wikipedia.org/wiki/Archaic_human_admixture_with_mo...

We probably got some immunity-related genes from neanderthals, but probably not red hair - red hair in neanderthals is caused by a different mutation that doesn't exist in humans.

Re: A chimp-pig hybrid origin for humans?

#49

Post by sageikosa »

a-priori wrote: post #20
gus_massa wrote: post #15

Earlier quoted context omitted.

Many hybrids are infertile. There are some documented cases of fertile hybrids in very related animals and very related plants (plants are weird!). http://en.wikipedia.org/wiki/Hybrid_(biology)#Hybrid_species But and hybrid between a chimp and a pig: simply no way! Even creating a live pig-chimp hybrid is probably almost impossible, a fertile pig-chimp hybrid would be a miracle.

It doesn't matter that fertile hybrids are unusual. For evaluating this theory, it only has to be possible to produce a fertile chimp-pig hybrid. Then, given a large number of chimp-pig... interactions, you can then assume that eventually one would be successful. (That said, before you interpret this as me supporting the theory, please read my top-level comment)

The problem is that those pigs and chimps that try to interbreed and fail would be wasting time and resources and end up falling behind in fecundity to their "breed true" cousins. Evolution would disfavor such behaviors as they would represent a vanishingly small percentage of the their respective gene pools.

Re: A chimp-pig hybrid origin for humans?

#50

Post by dougk16 »

sageikosa wrote: post #49
a-priori wrote: post #20

Earlier quoted context omitted.

It doesn't matter that fertile hybrids are unusual. For evaluating this theory, it only has to be possible to produce a fertile chimp-pig hybrid. Then, given a large number of chimp-pig... interactions, you can then assume that eventually one would be successful. (That said, before you interpret this as me supporting the theory, please read my top-level comment)

The problem is that those pigs and chimps that try to interbreed and fail would be wasting time and resources and end up falling behind in fecundity to their "breed true" cousins. Evolution would disfavor such behaviors as they would represent a vanishingly small percentage of the their respective gene pools.

Unless, perhaps, both particular species of ape and pig routinely had sex for pleasure (https://en.wikipedia.org/wiki/Animal_sexual_behaviour suggests it's possible), and just happened to cross paths. In this case, they're not really wasting resources as they would have been having non-reproductive sex anyway.
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