Once again I make an attempt to open the question of created kinds, or baramins, or whatever you want to call them: groups within which there is common descent but between which there is not. This is an opportunity for the creationists who frequent TSZ to school me on the subject.
I ask one simple question to begin the discussion: how many different kinds of birds are there? (It should be obvious why I chose birds, but the choice was, from a scientific standpoint, arbitrary.) As a followup, how can you tell? If there are indeed separately created kinds, I would think the divisions would be obvious. Would you agree, and why or why not? In any case, I’m not asking for precision; an answer within an order of magnitude will do.
Here’s my answer: 1; all birds belong to the same kind. In fact they form an infinitesimal fraction of a kind, since all life on earth is related. We have discussed the evidence many times here: nested hierarchy, etc. There are no joints at which kinds can easily be carved. How about you?
Nonlin.org:
You’re trying, and failing, to criticize something you don’t understand. Why not learn some evolutionary biology first, and save yourself some embarrassment?
Entropy:
Please don’t erase your comments, Entropy. It’s very bad form.
I agree its likely these creatures once had legs. yet they are a trivial type and its related to survival.
yes there is mechanisms to do this.
yet snakes are everywhere and in every type.
We have the biblical account. The big snakes have evidence of former bodyplans with legs.
its not the same thing.
Possibly i could put it better.
i mean that the snake/serpent of Eve fame was cursed, more, and so became legless. so when we look at all the snakes in all their diversity we must conclude they are of a original kind. This to justify missing their legs.
likewise, i think, there would only be one pair on the ark.
Finding some obscure lizardish thing with no legs does not make oUR snakes as also from the mechanism that made this creature legless..
Yet this thread was about kinds. i was using the snake to make a hard and fast boundary of kinds in gods eyes.
likewise with the dove/raven on the ark.
As usual, kind of hard to sort through the word-salad, but of course humans and chimps aren’t the result of a single shared ancestor. Takes two in terms of recombination, and rather more to prevent excessive inbreeding.
But no caution is needed to invoke a single ancestral species as a shared ancestor of humans and chimps, since evolution from a common ancestral species is the only process that supplies a large percentage of information that is the same in divergent sexual organisms–along with some differences–in the wild. Considerable evidence would be needed to show that any other process could yield the same results.
Glen Davidson
No I wasn’t making that claim (though I believe humans and chimps are related by common descent). Rather, I was trying to draw your attention to the fact that you demand an excessive amount of evidence for the common ancestry of humans and chimps. People have made that decision based on morphological characters, so why do you require details that you won be able to appraise anyway?
That’s a rhetorical question, obviously. Just wanted to point it out.
You are missing Glen’s point (as he predicted you would); snakes also have elongated bodies and serpentine locomotion, so something else has been in play besides the curse; adaptive evolution producing rather major changes.
And you fail, because you can’t tell me how to distinguish a snake from not-a-snake. You just tell me over and over again that an “obscure lizardish thing with no legs” ( there are hundreds of different legless lizards by the way) is not a snake, because it is not a snake and that should be obvious.
It is not obvious, Robert. What is that hard and fast boundary, precisely?
Meanwhile, how many different kinds of birds are there? How could you tell?
Yes and no. Their ancestors certainly flew, but they weren’t ostriches.
Why should either of these (though I’m not sure what “life systems” are) make them a separate kind?
I also don’t accept nonsense, or saltation, or the concept of “scientific proof”. So we’re in agreement there.
Corneel,
Tom was trying to make a case with molecular data. I am suggesting he looks at all the relevant data and not just the data he thinks might support chimps and man being the same created kind.
Alternative splicing, gene expression and data showing biological activity in the vitamin c pseudo gene have all become available in the last 5 years.
Yes, all indicating derivation from a common source.
Glen Davidson
No, Tom was trying to use the genomic distance measures you suggested to establish that the difference among members of the horse family (which most creationists have no issue with lumping into a single kind) are way bigger then between humans and chimps … and then you raised the bar.
Perhaps we should return to birds and revisit Hominidae later. I just learned there are two species of ostrich. Are they the same kind? How can we tell? Do we need to tease out all the alternative splicing patterns and possible hidden activities of their presumed pseudo genes to decide?
Corneel,
Corneel
Alternative splicing was in the first request. Tom lowered the bar to the point he was going to fool himself.
Both sequencing data and alternative splicing data are important as they determine protein isoforms. I would doubt that two ostrich species have different splicing patterns but I could be wrong. Why are they considered different species?
Simple. We ask Byers to check his Bible and report back.
No. The losing of legs right away meant another adaptation to survive. all creatures after the fall reacted this way. not new creations but quite changes in body plans.
Its not a fail but a excellent boundary and lesson.
In deciding what snakes are IS simply a list of traits. your lizard fails the list and has another list.
its not just being legless.
Nobody says your lizards are snakes. This because they group traits.
I believe that you initially were satisfied with DNA sequence variation and capability of interbreeding, but let’s not quibble about that.
I was wondering about that as well. The blue-necked ostrich (Struthio molybdophanes) got the status of full-fledged species only a few years ago. I note that it is still considered a subspecies by some. The seperate species status seems to be based on phylogenetic analysis of restriction-site polymorphisms in mitochondrial DNA. Here is the relevant paragraph:
Interbreeding with the other Ostrich populations seems possible, but troublesome:
OK, so I have done my homework; your turn. Can you tell whether these Ostriches represents types within a single kind. Or do we need alternative splicing patterns to tell?
Why doesn’t that book come with a handy species glossary?
Why Robert. Are you saying that elongated bodies and serpentine locomotion are novel traits that resulted from adaptive evolution?
Good. Tell me what’s in the list.
You’re just taking the “deny everything” attitude. That’s fine, but very boring. End of this story.
I call projection, and I call flounce. Don’t let the internet hit you on the ass on the way out.
Jesus. Next somebody will come up with some shit about Pluto not really being a planet.
Corneel,
This is very interesting. At first blush I would agree the Ostriches are the same kind. Also again I would doubt that splicing data would be different enough to give us any information.
I would say the next bit of data to get is nuclear DNA to see if there is similar divergence that the MtDNA shows.
On what do you base your agreement and doubt?
What, relevant to the question, would we learn from that?
I would argue that one needs more than alternative splicing to explain the isolated lymphatic erection system in ostriches…
What caused some birding independently to lose flight and others not? My independent theory would be that ostriches and emus where passing off literally pissing off too many predators… literally pissing on with the large amounts of stuff from their big bladders…
BTW: Did Harshman and you already agree that ostriches never flew? I lost interest in the OP once Harsh told the story of several, independent losses of flight or regain of flight, or both… I stopped reading fairy-tales to my kids years ago… why would I resume now and written by scientists?
You seem confused. I don’t know your source, but all known birds that have penises (most don’t) have lymphatic erection systems. It was once thought that ostriches were different, but they aren’t. See, for example, this.
Quick adaptation within a generation.
Yet they are not of the snake kind based on traits lists.
Its not my list. Its a list of traits that determines snakes or your lizards.
The snake once had legs and has evidence of that. your lizards have no evidence of having legs though they did once.
their change was perfect while snakes were changed for a curse and not pefert.
anyways the snake has great diversity and history of diversity.
its not like these minor reptiles.
there is a snake kind and its diversity is only from original bodyplans.
so its a boundary in nature.
Nothing gets through to you, but for the sake of truth and possible lurkers I would point out that while snakes do have evidence of having evolved from reptiles with legs, slithering lizards often have more apparent evidence of legs–often including basically useless legs. As the picture shows.
Legless (and nearly legless) lizards evolved rather later than did snakes, hence they tend to have more obvious vestiges of their past forms.
Glen Davidson
Why? This is great stuff!!
Sorry, I don’t understand what you are saying here. Snakes evolved these compensating features within ONE generation after losing their legs? Is that what you are saying?
colewd,
Johns questions are mine as well. Why are all ostriches one kind? What will we learn from nuclear DNA that mitochondrial DNA isn’t already telling us?
Bzzt, wrong. Slow worms develop limb buds during embryonic development. As for other legless lizards: see Glen’s excellent answer.
Indubitably. My question is; how can we tell? Not from the presence of rudimentary legs, it would seem.
Lizards are not a diverse group? Are there no zoo’s where you live?
So you keep telling me. And I keep on asking how we can distinguish snakes from not-snakes. What’s in the list of traits, Robert?
I love the way theists have theories about every fucking thing. I suppose the belief that the Lord of the Universe™ sports a personal love for them is conducive to that kind of hubris.
Corneel,
I am not sure all ostriches are one kind. Based on the extreme morphological similarity a single kind would be my working assumption. For all but one species the MtDNA was very close. The reason to get nuclear DNA samples is to see if there is correlation with the MtDNA outlier as far as variation with the rest of the ostrich sub species. If there is then the interesting question is where did the genetic change come from.
We are asking why that’s your working assumption, among other things. Please answer questions. It’s the polite thing to do, and it leads to a real discussion.
Did you mean “subspecies” here? Regardless, what is the relevance of that observation?
How is this relevant to the main question: whether they’re different kinds? What are the possible answers to the “interesting question”, and how would you decide?
GlenDavidson,
no. time would not matter in this. Evolutionists would not say that. if you were right then there would be still a selective need to finish off the last vestiges of legs on these lizards.
Its fine to see legs on these lizards.
Yet in the snake it was from God. So evidence of leggyness is also welcome.
I would of first thought these lizards with no legs/little would have no evidence left but its okay if they do.
Corneel,
The list is the list that is used. its not mine or relevant to me. your trying to say there is no difference between snakes and legless lizards.
Okay I was wrong about them having a perfect loss of legs but that works for me too.
they keep more of a leggy past bodyplan because they only needed to adapt as much as possible without legs.
Snakes don’t have leg bits, except in the big ones within the body, because they didn’t adapt to a new niche. It was a curse.
In the end you have no evidence for saying snakes once were leggy lizards who evolved.
Our evidence is the bible and seeing the snake as uniquely legless while seeing the legless lizard as only a poor adaptation showing its due to survival needs.
Anyways the thread was about birds and kinds and so snakes show a biblical kind.
Could you let us a bit more in on your motivations? There is morphological similarity with emus as well for instance. The cut-off seems arbitrary to me.
The authors of the paper suggest that the Great Rift Valley acted as a geographic boundary which allowed the populations to diverge. Is that an acceptable explanation?
The list is the list and snakes are snakes. Not very helpful. And no, I am not trying to say there are no differences between snakes and legless lizards.
So they both have evidence of a “leggy past” but they are still different? Sorry, not very persuasive.
I don’t understand how this differs from your own stance. Snakes had legs once right? And you agreed that they differentiated into different types right? Or are you taking issue with the claim of common descent with lizards? Of course there is evidence for that.
You seem to misunderstand. I never challenged your claim that there is such a thing as a snake kind (although obviously I don’t believe it exists).
What I object to is you suggesting it is somehow a clearly delineated kind, while being completely unable to give criteria for deciding which species are members of it. It is clear to anybody with a modicum of interest in snakes and lizards that the division is arbitrary, and that looking at loss of limbs is a particularly bad approach for deciding whether something is a snake. I hoped that you would eventually see that as well.
Corneel,
My motivation is to try to understand what the data is telling us. We have not been discussing emus. Is there any MtDNA data available from emus? John has generated some comparative DNA data in his 2008 paper. Have you looked at the comparison between the emus and the ostrich in John’s paper?
I need to take a closer look at the paper. Do you think there is a strong case that only one of the sub species was isolated?
John Harshman,
You are asking a question I clearly answered and saying it is polite to answer questions. Whats going on?
No, you haven’t. Just provide an objective criteria to identify kinds and reason why it’s a valid criteria. Spouting ambiguous & arbitrary crap like “extreme” morphological similarity or 1% sequence similarity doesn’t work. What is “extreme”? why “extreme” and not “moderate” morphological similarity? Why 1% and not 0.1% or 1.1% or 2%? This is not bible studies Bill, you don’t get to look at the data and make arbitrary stuff up.
Try something like “Separate kinds are characterized by A, B and C so we should expect to see X, Y & Z” and make sure there’s a logical connection between your characterization of kinds and the expected observations. It can’t be that hard, right?
Also, when confronted with counterexamples that smash your arbitrary criteria, don’t move the goalposts by proposing yet another arbitrary rule
You didn’t answer that question, and you didn’t answer most of the others people have asked you recently. Please look again. Why is “extreme morphological similarity” an indicator of same-kind-ness?
Before I go looking for emu sequences, I would like to resolve the issue of delineating kinds. Regardless of whether we are looking at morphology, DNA sequences or gene expression, we will always be facing the same problem: We have no rule for deciding when to lump species into a single kind, and given the russian-doll nature of ever more inclusive nested taxa (nested hierarchy, remember?) this issue will continue to haunt us. Does there exist a hard limit of morphological / sequence divergence that distinguishes distinct kinds?
I wouldn’t call it a strong case, but I think that it is a reasonable suggestion and I was wondering whether you would accept divergence of isolated populations and build-up of reproductive isolation within kinds at all.
John Harshman,
Why do you use it for identifying the same species?
Corneel,
No. I thought that is what we are working to discover.
Corneel,
There was a study I was looking at this morning with mice in Japan which showed a 3% worst cast MtDNA variation across the population.