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Originally posted by DeepThought….Dogs are all the same species. You can cross a Great Dane with a Chiuwawa and get viable offspring, although you probably need the Great Dane to be the female and use IVF.
You really need to read that post in the context of the other 20 or so I´ve written. I´m just trying to find where Kelly Jay stands on these issues. The point is that if he doesn´t believe speciation can happen even in a laboratory conditons then we are having a different argument to the one I think we are having. I think Kelly Jay is arguing that ev ...[text shortened]... what we have now is large and we really shouldn´t be suprised to find we are the product of one.
..… (my emphasis)
The similar thing can be said for closely related species in the wild.
Example; hybrid between a lion and a tiger :
http://en.wikipedia.org/wiki/Liger
Would you say that lions and tigers are all the same species?
I am not suggesting here that dogs are NOT of “all the same species” because in everyday English I personally would say they are not and this is just a matter of semantics but my point here is that exactly ‘how’ different and in exactly ‘what way’ two life forms have to be before they should be considered to be a different species is always going to be a subject of contention.
…What I’m talking about is the cell biology of the two species being sufficiently different that an EMBRYO just can’t form.
When you cross Tigers with Lions, the offspring have problems due to the size control genes going haywire and (depending on which way round the cross is) you end up with an animal that is truly huge. It couldn’t survive in the wild as it couldn’t hunt enough food to maintain its weight.
..… (my emphasis)
Never a less, using IVF, you can get such a hybrid EMBRYO to form -so using your implied criterion of what constitutes a separation of two species (and I apologise in advance if you didn’t imply this), Tigers and Lions are all of the same species!
But I think your implied criterion is too simplistic because there is no clear criteria for this.
I would also like to ask (probably Kay rather than you);
what is stopping two closely related breeds that can only hybridise using IVF rather than naturally but, using IVF, CAN produce viable offspring that can survive in the wild to continual to evolve until their genetic differences become so great that, EVEN using IVF, they would NOT be able to produce viable offspring that can survive in the wild?
-I mean, once you accept that evolution can go as far as splitting a species into two breeds that can only produce viable hybrids using IVF then what is stopping you from accepting that evolution can take the next small step by making some more changes to make the two breeds sufficiently different so that the CANNOT produce viable hybrids EVEN using IVF?
…I think Kelly Jay´s basic line of argument is that the outcome we have is improbable. Well, yes it is. the chances of the exact set of species we have now being the outcome when you look at what was around in the late Edicarian is kind of low. However what that misses is that the set of possible outcomes which are like what we have now is large and we really shouldn’t be surprised to find we are the product of one.
..…
Yes, I know what you mean. I have repeatedly made this point to him myself although using completely different words.
Originally posted by KellyJayMy response was:
Can you do me a favor, repost to this what it is you'd like me to
address?
Kelly
So we have:
X many right ways. (mutations or other events leading to a life form surviving)
Y many wrong ways. (mutations or other events leading to a life form dying out)
Now taking your previous statement:
given the enormous amount of variables to just occur not only in the right sequence, but at the right time and so on, should stagers the imagination in my opinion.
It appears that you believe X is significantly smaller than Y to the point that it stagers your imagination.
Do you have any good reasons for this belief?
Have you factored in the fact that natural selection significantly increases the odds of X ways surviving and Y ways being insignificant.
Let us take a specific example of mutations.
Lets suppose that there are 100 ways that a gene can mutate and result in a 'wrong' way.
Lets suppose that there is only 1 way that the same gene can mutate and result in a 'right' way.
At first sight you might think the odds of the 'right' way occurring are 1 in 100.
Lets also suppose that we have a population of 1000 rats in which a mutation in the gene occurs 10% of the time a rat conceives.
Do you realize that the probability that the 'right' mutation will occur and spread through the population is very close to 1? A near certainty.
Originally posted by Andrew HamiltonWolves, dogs, coyotes jackals and others can all interbreed with varying success.
I am not suggesting here that dogs are NOT of “all the same species” because in everyday English I personally would say they are not and this is just a matter of semantics but my point here is that exactly ‘how’ different and in exactly ‘what way’ two life forms have to be before they should be considered to be a different species is always going to be a subject of contention.
See:
http://www.messybeast.com/genetics/hybrid-canines.htm
The normal definition of species does not really include domestic animals so it would be hard to say whether different breeds of dogs are separate species.
The truth is that the word 'species' is really a grey edged term used for classification and anyone who makes concrete statements about what life can or cannot do with regards to species simply does not understand this.
Originally posted by KazetNagorraFruit flies are the most experimented on species.
I didn't know they got as far as fruit flies yet, but on the bacterial and multicellular level I'm sure you can find plenty on artificial speciation. Other than that, more obvious examples are certain species of livestock, who have been manipulated by man to the extent that there is no chance they'll survive in the wild.
Bacteria severely break the notion of species as I defined it above as they can exchange DNA horizontally (ie between quite different species) and it is believed that this can happen between domains (Archeans and Eubacteria), Much of the observed speciation in plants involves hybridization,
Look at the first reference on the wikipedia speciation page: http://www.toarchive.org/faqs/faq-speciation.html for a complete list of examples.
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Originally posted by Andrew HamiltonYes, the bio-chemical block I am talking about is a very strict definition of species. It is so strict that it is not useful for a lot of purposes. However for natural selection (*) to be a theory of the origin of all life you need to be able to show that complete speciation can occur.
Original post would be shortened - points raised I want to respond to are:
What is a species?
Ligers and tigons and bears - oh my!
When does speciation occur - how complete does it need to be?
[my wording]
Ligons and so forth are not viable, in the wild Tigers and Lions will not meet and will not mate if they do meet - in capitivity they get bored and a bit frisky...
It does not require IVF, but the offspring are not viable. Speciation is only partially enforced.
Interestingly the ¨folk¨ definition of species - dogs beget dogs and you can tell instantly if two animals are the same species by looking, seems to play a part in this. Animals can tell if their prospective mate is the right species or not (even with closely related species) due to smell, sight and so forth.
There seems to be several steps - isolation, a difference in form, behavioural speciation, biochemical speciation (my term - this is not used by biologists AFAIK). Having done a small amount of reading there actually seems to be a genetic mechanism to enforce speciation once it starts. Interestingly this means that the ancestral Eukaryotic cell found that there was a survival benefit to separating itself from other species (**). Which is particularly wierd given how much of a hybrid eukaryotes are. This creates a tension with notions of hybrid vigour - at some point hybrids stop being advantaged and start being disadvantaged.
(*) We should probably avoid the term evolution - that in itself is not contested - KJ simply has a different theory of evolution - by designer intervention.
(**) Terrible way of expressing it but there you are.
PS - re the gravity thread - it was clearly a typo.
Originally posted by twhiteheadThe casino analogy is quite a good one. An improvement to it would involve a poker tournament where you´d expect the better players to last longer - here you have the possibility of a good player can be knocked out before a bad one by bad luck.
Heavily edited DT
Do you agree that there is randomness used at casinos in their various gambling machines?
The result is the survival of the fittest.
Even when the environment does not change, species tend to evolve new traits that better enable them to survive.
No the result is not invariably the survival of the fittest. Survival involves luck. Species may gain new traits, but unless there are strong environmental limitations these new traits can be costly. Consider the following:
You have stated that only the genetically fittest survive to pass on their genes to the next generation. Well, look at peacocks. The standard evolutionary explanation for the tails is that females can tell the fitness of a prospective mate by how big their tail gets, and so there is a survival benefit to having the tail.
Now, I don´t believe this. I think that there is a benefit for the individual males, but not automatically for the species. For the tail to grow you first need a modification to the female peacock´s brain that gets the female to be more likely to select males with a large tail. This makes sense as at this stage it probably is an indicator of health so that initially there will be a species wide advantage to it. The problem is all of a sudden you have a characteristic that is sex linked. Males with big tail genes get all the luck and all of a sudden you have a species with big, colourful, expensive tails. What is worse, as the main selection pressure is to be selected the tail can end up protecting a whole bunch of less advantageous genes, which no longer interfer with the tails growth. So it is no longer the fittest, but but the ones with the biggest tails who survive.
I don´t want to get into a debate about the relative merits of peacocks having tails - this is an example of a situation where something potentially disadvantageous could end up being selected for quite strongly. To really analyse this properly would involve an assessment actual energy balances, costs, predator populations and so forth. I just think ¨survival of the fittest¨ is far too weak a model.
I think Kelly Jay has raised an interesting point which is how good is the theory of natural selection. I think where he has gone wrong is to ditch the natural part rather than the selection part.
There are a number of versions of natural selection - for example Dawkins in the Selfish Gene claims that selection occurs at the level of individual genes (I haven´t read the book, just a commentary), People like Steven Jay Gould talk about punctuated equilibrium. We´ve asked Kelly to name his designer, may be we need to state what exactly we mean by selection?
Originally posted by KellyJayAll this shows is that two new species can emerge from one population. I agree that it is somewhat different to the evolution of the kidney for instance.
Your suggesting that changes within a kind/family/whatever shows
us we can get new organs or systems that were never seen before,
that those types of changes prove this? Do we see flies at the
beginning and flies at the end? Can you show me a worm that grew
eyes, feathers, wings, and started flying in a lab? I'm very
comfortable with changes like that ...[text shortened]... og turning into a duck or
something along those lines, I'd say you win the discussion.
Kelly
I regard it as important because as speciation is a fundamental requirement for the theory of natural selection. If you can´t get new species the theory is as dead as a parrot.
In maths they talk about necessary and sufficient. Naturally occuring speciation is necessary for the theory of natural selection, but not sufficient for it to be proved.
The difficulty for us now is that soft tissue does not survive fossilization nearly as well as bone so there is not a vast amount of evidence about it´s history.
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Originally posted by twhitehead[/b]Thank you, I'll responsed to this.
My response was:
So we have:
X many right ways. (mutations or other events leading to a life form surviving)
Y many wrong ways. (mutations or other events leading to a life form dying out)
Now taking your previous statement:
[b]given the enormous amount of variables to just occur not only in the right sequence, but at the right time and so on ation will occur and spread through the population is very close to 1? A near certainty.
Kelly
Originally posted by DeepThoughtI never doubted a new species can emerge from one population,
All this shows is that two new species can emerge from one population. I agree that it is somewhat different to the evolution of the kidney for instance.
I regard it as important because as speciation is a fundamental requirement for the theory of natural selection. If you can´t get new species the theory is as dead as a parrot.
In maths they tal ...[text shortened]... ssilization nearly as well as bone so there is not a vast amount of evidence about it´s history.
as soon as you split a species into two completely different
enviroments I see this as occuring over time. We have variety of
themes with in life to me that is simply a reflection of what your
talking about, but and this is a huge "but" I don't see it going father
than that. As I asked for earlier we do not see a worm growing eyes,
feathers, wings, and have it learning to fly as you do different breads
of dogs or flies or something else being introduced into life.
Kelly
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Originally posted by twhitehead"So we have:
My response was:
So we have:
X many right ways. (mutations or other events leading to a life form surviving)
Y many wrong ways. (mutations or other events leading to a life form dying out)
Now taking your previous statement:
[b]given the enormous amount of variables to just occur not only in the right sequence, but at the right time and so on ation will occur and spread through the population is very close to 1? A near certainty.
X many right ways. (mutations or other events leading to a life form surviving)
Y many wrong ways. (mutations or other events leading to a life form dying out)
Now taking your previous statement:
given the enormous amount of variables to just occur not only in the right sequence, but at the right time and so on, should stagers the imagination in my opinion.
It appears that you believe X is significantly smaller than Y to the point that it stagers your imagination.
Do you have any good reasons for this belief? "
[/b]Yes, having seen first hand the end of a life that had something
go wrong I can tell you from talking to the heart specialist that it is
amazing at the percentage that go right. As soon as you have a
closed system like our circulatory absolutely anything that
compromises it like weakening the strength of the parts could cause
the pressure to rupture part of the system, we cannot have some of
the parts that feed others to just no longer be there, anything that
compromises anything will weaken or kill the life form in question.
What you are suggesting occurs is that through time with changes
occurring everywhere at once without a plan, purpose, and design not
only keeps life going, it allows it to through time become more and
more complex. This is the game in place, get it wrong dead end
results occur, change the environment drastically you can get dead
end results, the amount of things that have to be just right is, yes,
very huge, but if any of them go wrong in so many differnt ways those
number dwarf what must be right.
Kelly
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Originally posted by twhitehead"Have you factored in the fact that natural selection significantly increases the odds of X ways surviving and Y ways being insignificant.
My response was:
So we have:
X many right ways. (mutations or other events leading to a life form surviving)
Y many wrong ways. (mutations or other events leading to a life form dying out)
Now taking your previous statement:
[b]given the enormous amount of variables to just occur not only in the right sequence, but at the right time and so on ation will occur and spread through the population is very close to 1? A near certainty.
Let us take a specific example of mutations.
Lets suppose that there are 100 ways that a gene can mutate and result in a 'wrong' way.
Lets suppose that there is only 1 way that the same gene can mutate and result in a 'right' way.
At first sight you might think the odds of the 'right' way occurring are 1 in 100.
Lets also suppose that we have a population of 1000 rats in which a mutation in the gene occurs 10% of the time a rat conceives.
Do you realize that the probability that the 'right' mutation will occur and spread through the population is very close to 1? A near certainty."
[/b]I don't have to time to point out the holes of this at the moment, I'll
get back this later.
kelly
Originally posted by DeepThought….However for natural selection (*) to be a theory of the origin of all life
Yes, the bio-chemical block I am talking about is a very strict definition of species. It is so strict that it is not useful for a lot of purposes. However for natural selection (*) to be a theory of the origin of all life you need to be able to show that complete speciation can occur.
Ligons and so forth are not viable, in the wild Tigers and Lions ...[text shortened]... e way of expressing it but there you are.
PS - re the gravity thread - it was clearly a typo.
..…
Perhaps you didn’t mean the above statement literally but it is incorrect to say natural selection is a theory of the “origin” of all life because it isn’t. It is correct to say that the theory of evolution (and not just natural selection) is a theory of the diversity of all life (and NOT its origin) or, alternatively, it is correct to say that the theory of evolution is a theory of the origin of species (and NOT all life).
-this seems to repeatedly be a source of constant confusion throughout these threads.
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Originally posted by twhitehead….the probability that the 'right' mutation will occur and spread through the population is very close to 1? A near certainty.
My response was:
So we have:
X many right ways. (mutations or other events leading to a life form surviving)
Y many wrong ways. (mutations or other events leading to a life form dying out)
Now taking your previous statement:
[b]given the enormous amount of variables to just occur not only in the right sequence, but at the right time and so on ation will occur and spread through the population is very close to 1? A near certainty.
..…[/b]
Correct (assuming that what you mean by the ‘right way’ is the way that leads to better adaptation)
And for those who don’t see why; a beneficial mutation would be selected by natural selection so to spread to the whole population while a debilitating mutation would be selected OUT by natural selection so as to be eliminated from the whole population -thus even if the debilitating mutations outnumber the beneficial mutation 1000,000,000,000,000,000 to one, natural selection would STILL make only the few beneficial ones become predominant in the population as a whole.
Originally posted by Andrew HamiltonWhen you look at a race, is getting out of the starting block part of
[b]….However for natural selection (*) to be a theory of the origin of all life
..…
Perhaps you didn’t mean the above statement literally but it is incorrect to say natural selection is a theory of the “origin” of all life because it isn’t. It is correct to say that the theory of evolution (and not just natural selection) is a theory of the ...[text shortened]... ll life).
-this seems to repeatedly be a source of constant confusion throughout these threads.[/b]
the race, or is it only when the runners are on the track running?
Kelly